Glossary of RF Terms

1 mm Connector
An RF connector that can perform up to 110 GHz. It performs at the highest frequency when compared to other millimeter wave connectors on the market.

1.0-2.3 DIN Connector
A micro-miniature coaxial connector that is 40% smaller than the 1.6-5.6 connector, with transmission frequency up to 10 GHz and an impedance of 50 Ohms

1.6-5.6 Connector
A coaxial connector which is usable for frequencies at max of 12GHz. They were designed to be stable, compact, and have high data rates.

1.85 mm and 2.4 mm Connector
Both 1.85 mm and 2.4 mm connectors are physically compatible and require 5/16" wrench. They will not thread onto SMA, 3.5,or 2.92 mm connectors, and are commonly known as "V" connectors.

2.92mm Connector
Both 2.92mm and 3.5mm connector styles mate with SMA connectors, and with each other. These connectors offer higher maximum frequencies than SMA connectors. 2.92mm connectors usually work up to 46 GHz.

3 dB Bandwidth
The bandwidth described by the width between the points at which the signal's strength is reduced by 3db.

3.5mm Connector
Both 3.5mm and 2.92mm connector styles mate with SMA connectors, and with each other. These connectors offer higher maximum frequencies than SMA connectors 3.5mm connectors usually work up to 34 GHz.

4.1-9.5 Connector
4.1-9.5 connectors are especially rugged and weatherproof due to their screw-lock mechanism. They are generally operable up to 10 GHz and offer low reflection ratios and low PIM performance.

7/16 Connector
A coaxial cable that works with medium/high power low transmission up to 8.3GHz that provides little attenuation. Usable in more harsh conditions (such as in the presence of moisture)

ABCS is an acronym that stands for Antimonite-based compound semiconductors. They are semiconductors that are capable of running with only 100 millivolts and have applications in low noise amps.

Ablation, RF and Microwave
The separation of radio and microwave frequencies.

Loss of power in fiber optic cable, due to heat, which is also known as scattering.

Acceptance angle
The angle that is acceptable for signal transmission in fiber optic cable, which is measured from the centerline of the fiber optic core.

Acousto-optic modulator
A device the uses sound waves in order to vary the phase and amplitude of a light beam (i.e. a laser).

Active port diameter
The diameter of the area in the particular part of a light source in which light is guided to or from an optical fiber.

Connectors that allow the connection between two cables whose male-female types do not necessarily match. Adapters exist in male to male (a barrel), female to female (a bullet), and male to female (a connector saver) connectors.

Active Electronically Steered Antenna

Alloys, Low Expansion
A material that has been experimented on by engineers for over 100 years because of their temperature expansion characteristic. Alloys that have low expansion are often used in glass feedthroughs and microwave housings.

Alumina is a ceramic material used mostly in the Microwave Integrated Circuit industry. It is offered in 96% and 99.5% concentrations, each of which have different applications. For example, high-temperature circuits generally use 96%, while thin-film circuits use 99.5%.

Material used as either a conductor or packing material. Symbol: Al, Atomic number: 13.

Aluminum Nitride
A material classified in the ceramics family, AIN has high thermal conductivity and is often used in heat sinks, IC packages, and substrates in electronic packages. A safe substitute for Beo substrates.

A device whose purpose is to take an input signal and increase its amplitude by a certain amount.

Amplifier, Active Directivity of
Measurement of the potential effect of output impedance based on an amplifier's source match, or the effect on input impedance based on an amplifier's load match. Larger active directivity is better. Origin: Mini-circuits.

Amplifier, Balanced
A device that has two amplifiers run at 90 degrees difference in phase transmission. At the input, two signals are set 90 degrees apart, and at the output the difference is removed so that they are at the same phase.

Amplifier, Classes of
Types of Amplifiers, classified based on the bias point (quiescent point "Q"). In class A, the bias point divides the distance between the saturated current and pinch-off current in two. Examples include gain-block and linear amplifiers. Class B amplifiers only conduct half of a signal's cycle. Class AB amplifiers' bias point lie somewhere between class A and B, which provides a good balance between gain, efficiency, and power. In class C, a tuning circuit filters the signal for a single frequency, and behaves like a class B. Classes D, E, and F are switching amplifiers.

Amplifier, Conditionally Stable
An undesirable condition where the amplifier will oscillate under a specific load or source impedance.

Amplifier, Directivity of
A parameter used represent the amount that the input impedance is influenced by the load impedance and also how much the output impedance is affected by the source impedance.

Amplifier, Distributed (Traveling Wave Amplifiers)
Distributed Amplifiers are used as amplification solutions for up to 100 GHz, and down to DC applications. These amplifiers use the capacitive qualities of FETs as well as high-impedance lines to mimic a standard 50 Ohm line for impedance-matching.

Amplifier, Doherty
A type of amplifier that is often used in communications (radios), and performs more efficiently than balanced amplifiers.

Amplifier, Dynamic Range of
The range of power wherein the amplifier operates linearly.

Amplifier, Feedback of
Two types of feedback exists, series and parallel. They can be used to change the characteristics of an amplifier such as its gain vs. frequency, its K-factor, and its input matching characteristics.

Amplifier, Feed-forward
Feed-forward Amplifiers are used in applications where low distortion is key, such as in base station equipment.

Amplifier, Gain Block
Gain block amplifiers are simple and convenient and are used for general purpose applications. They offer a wide bandwidth, but usually at the cost of efficiency and noise.

Amplifier, Gain Flatness of
Gain Flatness refers to the variation in gain over the bandwidth, and is represented as a value ±dB. To calculate this value, subtract the highest gain in the band from the lowest and divide by two.

Amplifier, Gain of
A ratio of the output of an amplifier over its input. The equation for gain is in decibels and is define as follows: G = 10 log10(Out/In).

Amplifier, Harmonic Distortion of
Harmonic distortion presents itself in the form of output frequencies at integer multiples of the input frequency. It is generally caused by non-linearity in the amplifier, and is described in terms of the relative level to input power.

Amplifier, Isolation of
The ratio of applied output power to measured input power.

Amplifier, Linearity of
Refers to how well the output of an amplifier can be described by a linear function of the amplifiers input. In other words, the output is scaled by a constant factor of the input without much distortion.

Amplifier, Log
An amplifier in which the output voltage is scaled by the log of the input.

Amplifier, Low Noise (LNA)
An amplifier that is used to take weak signals and amplify them so that they can be more easily used.

Amplifier, Noise Factor of
Noise Factor is the ratio of the relative amount of noise at the input signal compared to the relative amount of noise at the output signal

Amplifier, Nonlinearity of
Amplifiers can only magnify a signal so much. At small input signals, the gain in the signal appears to be linear, however at large input signals, the output will reach a maximum value and may no longer be the same gain as with the small signal, hence non-linear.

Amplifier, Power
Takes a small signal and increases it to make a large signal.

Amplifier, Push-Pull
A device that uses two amplifiers which have 180 degrees difference in phase.

Amplifier, Reverse Gain of
The ratio of input over output when power is applied at the output amplifier, and the input power is measured.

Amplifier, Tube
Amplifiers that uses vacuum tubes to amplify a signal.

Amplifier, Wideband
Amplifiers that are capable of amplifying signals in a wide range of frequencies.

Amplitude refers to variation in value of a signal relative to some point, called its zero. Words such as "peak", "maximum" and "rms" are often used to describe the type of amplitude.

Amplitude Balance
The difference in peak-to-peak amplitude (measured in dB) between a power divider's output ports over a specific range of frequency.

Amplitude Match
A comparison between a reference filter and a filter being tested which analyzes the absolute difference of the amplitude response.

Amplitude Modulation Measurement
An accurate measurement of modulation levels which is acquired through a spectrum analyzer.

Amplitude tracking
Difference in amplitude between a test filter and a reference filter.

A continuously varying signal (such as sound waves). The bandwidth and frequency of an analog signal is measured in Hertz (Hz).

Angle of Arrival
Angle of arrival is the angle at which the radio wave collides with the antennas.

Angstrom ( Å )
Named after Anders Jonas Angstrom, the Angstrom is a length equal to one tenth of a nanometer

Angular Misalignment Loss
The energy that is lost in an optical signal because two optical components are not properly aligned.

The anode, generally paired with a cathode, is a positive terminal for a component. Being that it is positive, electron flow is directed toward the anode.

A device which interprets electrical signals/radio waves and transforms it to the other form (signal to waves, waves to signal)

Antenna, Horn
A horn shaped directional antenna, designed by William T. Slayton in 1954.

Antenna, Microstrip Patch
A flat antenna which sits atop a microstrip, with a wide beam and a narrow bandwidth.

Antenna, Monopulse
An antenna capable of gathering angle data with only a single pulse

Antenna, Vivaldi
Vivaldi antennas, also known as "tapered slot antennas," are used for their surprisingly large bandwidth and ease of fabrication.

Antimonide-Based Compound Semiconductors
A semiconductor device that only requires 100 millivolts to operate. Has applications in low power systems

Anti-Reflection Coating
A material which is applied to a surface and is used to reduce the amount of reflection and increase light transmission

APC-7 Connector
APC is an acronym for Amphenol Precision Connectors. APC-7 Describes a 7 millimeter connector. It is a coaxial connector used for microwave signals for 18GHz frequencies maximum.

Arbitrary Waveform Generator
A piece of electrical equipment used to generate waveforms.

Arc Suppression Diodes
Diodes used for arc suppression. The goal of arc suppression is to minimize the amount of sparks created when two contacts that are passing current are separated.

The loss of amplitude of a signal as it passes through a medium

Attenuation Accuracy
The magnitude of variation in attenuation from the expected value across the operating band.

Attenuation Coefficient
Also called linear attenuation coefficient, the attenuation coefficient is calculated by summing the absorption and scattering coefficients. A large attenuation coefficient means that a signal is quickly weakened as it passes through a medium.

Attenuation Constants
The reduction of amplitude in voltage and current. The reduction is an exponential function which changed with line length.

Attenuator, Continuously Variable
An attenuator whose attenuation value can be changed along a series of continuous values.

Attenuator, Digital
A type of attenuator that can be controlled by digital signals. The number of attenuation states it has depends on the number of states the digital signals have.

Attenuator, Flatness of
The total variation in the attenuation of an attenuator over a specific range of frequency. Flatness typically worsens at higher frequencies.

Attenuator, In-control Isolation of Bi-phase
The electronic attenuator's insertion loss, which depends on the transformer used to give coupling from the RF input to the internal diodes, and is independent of the amount of control current. It is measured from the RF input to the control port.

Attenuator, In-out Isolation of Bi-phase
The insertion loss, when no current flows through the control port, from input to output

Attenuator, Insertion Loss of Bi-phase
The loss in power from input to output at a particular input current.

Attenuator, L-Pad
Used to match two impedances. This particular type of solution results in signal loss

Attenuator, Maximum RF Power of
The maximum power that can be supplied to the attenuator without overheating.

Attenuator, Reflection
Contains a four-port quadrature coupler, consisting of two matched terminations on the through and coupled ports. These terminations must show an impedance that is at least partially real in order for the device to work.

Attenuator, Return Loss of
Measure from one port while the other port is connected to a 50 or 75 ohm termination.

Attenuator, Step
Divisions in which the attenuator can be set to reduce the signal by specific amounts.

Attenuator, Switchable
Switchable attenuators consist of two general categories: switched network attenuators and switched element attenuators. They offer electrically or mechanically controllable attenuation states.

Attenuator, Switched-Element
Similar to a pi pad network using resistive elements capable of realizing multiple values. It uses field effect transistors for switching.

Attenuator, Switched-Network
Versatile attenuators that can that can support multiple values of attenuation.

Attenuator, Temperature Compensating Fixed
Used with amplifiers so as to counteract the gain vs. temperature effect amplifiers. In these types of attenuators, the loss of the attenuator decreases as the temperature increases.

Attenuator, Variable
Attenuators which can change the amount of attenuation via an applied voltage.

Attenuator, VSWR of
Voltage standing wave ratio is a representation of signal reflection in RF devices. In attenuators, VSWR is a metric describing the impedance mismatch between the input and the attenuator.

Avalanche Photodiode (APD)
A light sensor which is capable of detecting weak light signals and needs high voltage to operate.

Axial Ray
Light that travels along the same axis as the fiber.

The angle from a reference zero point along the horizontal axis. It is usually represented by the Greek letter phi (?) or abbreviated AZ.

Backplane Panels
PC cards or other panels can be plugged into this type of interconnection panel. Backplane panels range from PC motherboards to a metal frame mounted with individual connectors. Panels have automated wiring.

Scattered light that travels in the opposite direction of the light,

Backside Processing
This term is comprised of three to four critical process steps lumped together. It takes place after final-front side, in which the wafer, which was previously thinned to the desired thickness of the RF designers, is flipped face-down and mounted onto a high-tech wax material.

Derived from the words BAL-ance and UN-balance. A balun is a device that changes an unbalanced signal to a balanced one or vice versa.

Band Reject Filter
A band reject filter passes all frequencies above and below a specific band of frequencies. The frequencies in this band are stopped from passing.

Band-gap represents a material's ability to resist breakdown under high voltage. The higher a material's band-gap, the higher its breakdown voltage, and the more power it can withstand.

Bandpass Filter
A filter that lets a specific range of frequencies pass, while rejecting higher and lower frequencies.

The width of the frequencies between the two points where half the power of the signal is lost.

Barrier Seal
A material which seals the gap between the insulator (dielectric) and the conductor (inner and outer), preventing gasses and moisture from permeating the connector it is mounted on.

Bayonet Coupling
A method of connection in which a rotating peg-and-slot mechanism secures the plug and receptacle together.

Beam Divergence
The widening of a beams diameter as a result of it traveling farther from the source.

Used to split an optical beam into several beams

Bending Radius
The minimum radius at which a cable is still able to successfully transmit a signal. If the radius of the cable becomes any less the signal will not be properly transferred.

Bessel Filter
A Bessel filter is an analog filter that displays constant time delay and preserves the wave shape of filtered signals in the pass-band.

Bias Networks
A network used to set the quiescent operating point of a FET in a device.

Bias Tee
A type of diplexer, used to supply DC voltage or current to RF devices.

Bit Error Rate (BER)
The number of errors divided by the overall number of bits.

Uses radio waves of short wavelength in the ISM band from 2.4 to 2.485 GHz in order to send and/or receive data over short distances. Commonly used in personal electronic devices and in-home networks.

Blind-Mate A connector used in microwave applications to 18 GHz - 26.5 GHz . BMAs utilize a slide-on interface and are designed to allow minimal radial and axial misalignment.

BNC Connector (50 Ohms)
This is a type of coaxial connector that has a two stud bayonet coupling mechanism, and is used for telecom and data system applications that perform up to 4 GHz (maximum 10 GHz). BNC connectors make fast and easy connections, and are very reliable.

BNC Connector (75 Ohms)
A coaxial connector with a Bayonet fastening mechanism.

A connector appropriate for shielded twin-axial cables. The connector uses a bayonet coupling system.

Boltzmann Constant
A constant whose value is 1.38 x 10^-23 J/K.

Bonded Assembly
A method of assembling connectors in which an appropriate adhesive bonds components together, sealing them from the elements while not interfering with the connector's electrical properties.

The direction that an antenna physically pointed to achieve maximum object illumination.

Boresight error (BSE)
Difference between the physical or optical boresight and the electromagnetic boresight.

Similar to welding but uses lower temperatures and materials that melt at lower temperatures.

Commonly used to refer to the connector mounting method. Bulkhead connectors are made to be inserted either from the front side or rear (component) side of a panel.

Butted Contact
Conductors which connect on their axes without overlapping.

Butterworth (maximally flat amplitude)
A filter that has lower stop band attenuation, group delay flatness, and overshoot than Chebyshev. It also has best in-band amplitude flatness.

C Connector
A coaxial connector capable of frequencies up to 11 GHz uses bayonet coupling for connection.

A material capable of passing some signal usually surrounded by strengthening strands and a protective jacket.

Cable Assembly
The cable itself along with the related hardware.

The primary electrical property of capacitor, measured in Farads. It is a measure of energy storage.

Capacitor, Charge-Storage
Capacitors are capable of storing a charge/voltage in their plates.

Capacitor, DC Blocks
Stops the flow of DC current through the use of capacitors.

Capacitor, Electrolytic
This kind of capacitor is usually made of tantalum, and provides the highest capacitance density. They are polarized, and often used for filtering power supply for microwave circuits. However, they are not microwave quality. At least two electrolytic capacitors are needed for linear regulators to remain stable (one on the input and one on the output).

Capacitor, Multi-Layer Ceramic
Capacitors with large capacitance to volume ratios utilizing a ceramic material as its dielectric. Because of their size, they are ideal for use as surface-mount devices on PCBs.

Capacitor, Single Layer
Capacitors using a single thin film as a dielectric, which are ideal for high frequency uses. They are often used in systems using frequencies higher than 110 GHz.

A terminal on an electrical component where electrons flow into. The terminal in which the electrons leave is known as the anode.

Center Frequency
The mean(average) frequency of all of the frequencies in the bandwidth of a given filter. See Bandwidth.

Center Frequency
The bandpass filter passbands midpoint, which is the mean of the two -3 dB frequencies.

Characteristic Angle
The angle in which a certain mode travels down an optical fiber. Also see: Mode.

Characteristic Impedance
The ratio of the current and voltage phase at any place along the transmission line, given that only one wave travels down a line.

Chebyshev (equal-ripple amplitude) Filter
A very popular filter configuration offering very high stop-band attenuation and overshoot, but at the expense of group delay.

Chebyshev Filter
A filter that more quickly attenuates signals which are beyond the cutoff frequency and that has a predetermined pass band ripple.

A passive device whose purpose is to control the flow of the incident signal through one of its three ports.

Cladding Mode
The cladding has a larger refractive index than the material surrounding it. 

Closed Entry Contact
A female contact that is made to prevent an entry of a probing device or pin that has a diameter which is greater than the mating pin.

Coaxial Cable
Cable that is used for transmission of radio signals. The cable consists of a core which transmits the signal, a dielectric insulator, a metallic shield, and plastic jacket.

Coaxial Cavity Resonator
Transmission line sections of certain termination resistances and lengths that have similar resonance characteristics to oscillating circuits that contain resistance, inductance, and capacitance.

Coaxial Connector
This type of connector provides a connection between two lines that not only have the same characteristic impedance, but also are as reliable, reflection-free, and uniform as possible. It has good electrical transmission characteristics, offers a insensitivity of a high degree toward electromagnetic interference, and is simple to connect and disconnect. The characteristic impedance of the different cables can be well matched to the characteristic impedance of the coaxial connector.

Light which not only has waves that are in phase with each other, but also have identical frequencies. This kind of light is only produced by lasers.

To make rays of light or particles accurately parallel. Parallel light rays, like in a laser beam, are collimated.

A common point in a single fiber collects optical power from several input fibers in this passive device. Also see: Coupler.

How well a material can conduct current. It is the inverse of resistance and has units of 1/Ohm

A conductor is a material that, simply put, conducts electricity and allows current to flow. Technically speaking, the definition of a conductor dictates that the material be between 10^6 and 10^4 Ohm-cm. Outside of that range lie superconductors, semiconductors, and insulators.

Connector Gender
The gender of a connector can be male or female. Male connectors have a protruding connection, while the female connector has a crevice where the male connector can sit. There do exists some "sexless" connectors when can connect to any other sexless connector of the same type.

Connector, Elbow
A connector that is bent so that it can connect two components that are not parallel to each other. These connectors exist in right angle connectors and swept connectors which are better at high frequencies than angle connectors.

Connector, Push-On
Connectors with a simple "push-on" mechanism. May be used when there are not threads on the components or simply for ease of use.

Connector, Reverse Polarity
For a connector to be considered "reverse polarity," its inner conductor's gender must be the opposite of the outer conductor or sheath. For example, a male reverse-polarity connector has a female inner conductor contact.

The part of the connector that physically touches the other connector through which a signal is passed.

Contact Cavity
The area of a connector on which the contact must be fitted.

Contact Durability
A number defining the expected number of connections that a connector can withstand before performance dips below a certain standard.

Contact Engaging & Separating Force
The amount of force required to remove and insert pin-and-socket contact connectors. The required specification will vary based on product application.

Contact Plating
A plating used on contacts that provides protection for the contact.

Contact Pressure
The pressure between mating surfaces exerted on each other.

Contact Resistance
The electrical resistance of a connector under normal use, as measured at a particular testing current.

Contact Retention
The smallest axial force that a contact has to endure while it is connected in its appropriate position.

Continuous Wave
A wave which has a constant amplitude.

The process of transferring heat through the air.

Conversion Loss
A property of mixers referring to the total loss of signal power from input to output. It is measured by inputting a known control signal and LO, and measuring the output.

The separation length of a connector when one a flat surface between the highest and lowest lead.

The center of an optical fiber, often made out of glass, that is used to transfer light.

A device used to take one signal at a single input and splits it among several outputs. It can also take several inputs and merge them into one output signal.

Couplers and Splitters
Components used to combine or split microwave/RF signals. Both components work in both directions, with splitters either dividing or combining power, and couplers either sampling or adding a signal to a main path.

Coupling efficiency
The fraction of light that exists at the source compared to the amount of light that passes into the optical fiber.

Coupling loss
The amount of power lost at discrete junctions (i.e. fiber-to-detector, fiber-to-fiber, source-to-fiber) in a fiber optic link.

A percentage which indicates how much the shield or broad covers the component underneath.

To deform a connector ferrule around a cable to make an electrical connection.

Crimping Dies
The part of a crimping tool that makes contact with the terminal.

Crimping Termination
A connection that is made by mechanically crimping a metal sleeve with crimp dies, presses, or pliers, in order to secure in to a conductor.

Crimping Tool
A hand-held tool used to crimp, but not sever, certain electrical components such as contacts, ferrules, or terminals. Crimping tools are most commonly used to secure connectors to a coaxial cable.

Critical Angle
The smallest angle, relative to the normal, that light may contact the outer edge of a medium so as to ensure total internal reflection.

Crosstalk is mutual interference of signals in electrical systems or adjacent transmission lines, which is caused by magnetic, electromagnetic, and/or electrical coupling.

Crystal Oscillator
A circuit that uses a vibrating crystal to produce an electrical signal at a specific frequency.

Cutback technique
Used to measure the attenuation/distortion of a fiber by taking measurements with the full cable length and another when the cable has been cut at a point less than full length.

Cutoff Frequency
The largest frequency at which a signals is not attenuated much. Any frequencies beyond the cutoff frequency become greatly reduced.

One complete sequence of periodically occurring values, measured from a relative zero to some maximum value and back.

Dark current
A current that a photo detector creates despite the fact that there is no light or voltage supplied to the detector.

dB – (Decibel)
The logarithmic unit measuring the ratio of input to output. It is generally used as the unit for gain and loss.

Power ratio for a signal carrier. Typically, this unit is used for measuring passive intermodulation distortion.

Decibels that are related to 1 mW. The microwave industry uses 1 mW as the standard unit to measure power level. Examples: 0 dBm = 1 mW, +10 dBm = 10 mW, +20 dBm = 100 mW, etc.

A decibel watt describes the power of a signal relative to a watt in decibels.

DC block
An electrical component, often a capacitor in series or a parallel coupled line, that separates DC voltages from an RF signal.

DC return
A DC ground is added to an RF line through DC return. For example, it can provide a path for the current of a series diode to return to in a PIN diode switch.

Calibration of ports in measuring or testing equipment.

A component used to split the desired data signal from the carrier signal.

A component used to convert light or infrared radiation to electrical signal, used in fiber optics.

When a wire, pad or lead becomes disconnected from its soldered connection. This could be due to prolonged exposure to temperature, inconsistencies or impurities.

A insulating material is dielectric if it can transmit an electrical force. In coaxial, the dielectric changes the cable's impedance, capacitance, and other characteristics.

Dielectric Constant (Permittivity)
A property that determines how a material is affected by an electric field.

Dielectric Loss
A loss in power due to heat dissipation in the dielectric material.

Dielectric Strength
The maximum voltage at which an insulating material can withstand before electrical breakdown.

Dielectric Withstanding Voltage
Also known as breakdown voltage, this is the potential at which dielectric material breakdown occurs.

Diffuse Reflection
The opposite of spectral reflection, diffuse reflection describes light which bounces in arbitrary directions after impacting a surface.

The German standards organization. A type of electrical connector used for various applications.

Diodes were first used in crystal radios about 100 years ago, and are now used in the switching, mixing, detection, and generating of microwave signals. Diodes are 2-terminal, nonlinear semiconductors.

Diode Laser
A diode laser is a solid state semiconductor device which has at least one p-n junction that, under specified conditions, can emit stimulated, coherent radiation.

Diodes, Gunn
A diode that is used as an electrical oscillator which produces microwaves.

Diodes, PIN
This type of diode can be made on silicon or GaAs. "PIN" is an acronym that stands for P-type, intrinsic, and N-type, which corresponds to a stack of semiconductor materials.

Diodes, Schottky
Diodes which are composed of a metal connected to a semiconductor. Schottky diodes can be accidentally created by using connectors with different metals.

Diodes, Zener
A diode similar to an ideal diode but also allows the flow of current in the opposite direction when the voltage has reached a certain level known as the breakdown voltage.

Dip Solder Terminal
Ends on connector that are place in the holes on a printed circuit board which are then soldered to keep them in place.

A circuit which takes an input and then output it to one of two output ports depending on the frequency of the signal. A signal in a certain bandwidth gets output to a specific port.

Direct Current (DC)
Current traveling in one direction as opposed to alternating current which changes directions.

Directional Coupler
A passive device used couple a defined amount of power in a transmission line to a single port, enabling the signal to be used in another circuit. Unlike bi-directional couplers, directional couplers only couple power signals flowing in one direction.

Directional Couplers, Average Power of
The handling capability of the CW average power through the coupler's main line under matched load conditions with one-way transmission.

Directional Couplers, Bandwidth of
The set of frequencies where the performance is lands between certain margins. 

Directional Couplers, Coupling Coefficient of
Coupling coefficient of directional couplers is the ratio of the incident power fed to the couple port through the main port when reflection-less terminations have terminated all ports. This is measured in dB.

Directional Couplers, Coupling Flatness of
The max peak-to-peak difference at a range of frequencies in the coupling coefficient.

Directional Couplers, Coupling Loss of
The power lost from the main line by sampling the signal with a coupler.

Directional Couplers, Coupling Tolerance of
Tolerated variation in power from unit to unit conversion during nominal coupling.

Directional Couplers, Directivity of
Defined as the ratio of the isolation (see Isolation) of the coupler to its coupling factor.

Directional Couplers, Main-line Loss of
Main-line loss of directional couplers is the change in load power, which is caused by the insertion of the coupler into a transmission system, where ports of the coupler are connected with reflection-less terminations. This includes the effect of power moved to the coupled line.

Directivity, a term generally associated with antennas, refers to the ratio of the measured power density at its peak point, versus the ideal power density.

A discrete component is one that does not need other components to function such as resistors, LED's, etc.

Dissipation is energy that is either lost or unusable. Electrical energy is lost (dissipated) in dielectric materials, usually in the form of heat.

The deviation from input of the output wave form. One example of this phenomenon is clipping.

Dual Directional Coupler
The combination of two 3-port couplers wherein the mainline is shared, and the terminating ports are connected. This allows for bi-directional use of the couplers.

An optical cable containing two fibers.

The lowest voltage level that a conducting material can withstand.

Dynamic Range
A range for which if a given signal is in that a electrical component can amplify the signal without distortion.

Efficiency, Antenna
A measure of resistive loss in an antenna, calculated by dividing the actual emitted power from an antenna by its theoretical value.

Electromagnetic Compatibility (EMC)
The capability of a system to not be affected by electromagnetic interference.

Electromagnetic Interference (EMI)
Electrical/Electromagnetic energy that can interfere with other desirable signals or equipment and cause problems.

Electromagnetic Spectrum
The range of all possible frequencies of electromagnetic radiation usually considered between ELF (3 Hz) up to Gamma Rays (300 EHz).

An elementary particle with what is known as the fundamental charge: 1.6 x 10^-19 Coulombs. The movement of electrons conductive materials generates current and voltage, and causes the phenomenon we study in the RF field.

Electronically Steered Array
A smart antenna system that utilizes beam forming rather than physically moving the azimuth to direct the signal.

Electro-optic Effect
A change in the properties of a material as a result of an electric field. This also encompasses a change of absorption and a change in the refractive index as well as the permittivity.

Process of placing metallic layers of varying thickness on a base metal to obtain some electrical property.

The angle between +90 degrees (up) and -90 degrees (down), starting from 0 degrees horizontal. It is usually represented by the Greek letter theta (?).

Elliptic Function
A function used in finding the  amplitude filter for a particular circuit. However, this filter has a worse transient and phase response compared to classical transfer functions.

Envelope Delay
Time delay caused by a filter, as noticed by the envelope in an AM signal. It is linearly proportional to the phase-shift versus frequency curve for the filter.

Equilibrium Mode Distribution (EMD)
EMD is the condition in which the distribution of relative power among the propagating modes is independent of length in a multimode optical fiber.

Equivalent Line Circuit
Equivalent line circuit is calculated by line parameters per unit length of the section of line that is being considered. This represents the line circuit through circuit elements that are locally concentrated.

A word describing metal alloys that melt and solidify at the temperature. This is a possible property of soldering material.

Eutectic Solder
A solder alloy with 63% Tin and 37% Lead in composition. It is most common because of its low melting point.

F Connector
A type of coaxial connector with high electrical and mechanical stability, and is often used in satellite TV, MATV, and CATV equipment. It is very suitable for measurement applications that perform up to 4 GHz since it contains a screw-lock system.

Fall Time
The time it takes a signals to drop  from 90% of its maximum to 10% of its maximum. Fall times may also be measured using the 80%, 20% points.

A feed-through is a terminal block or connector which permits bussing and simple distribution of electrical circuits by using double-ended terminals. This term is also used to describe a bushing inside a wall or bulkhead that separates compartments at varying levels or pressure, that has terminations on each side.

Ferrule (Coaxial)
A short, hollow metal tube generally used for joining or reinforcing two pieces of wire or cable or to make a termination on the end of a cable.

FET, or field effect transistor, has three terminals known as the gate, drain, and the source. It has uses in microwave amplifying and switching.

A conductor or core that carries light; an optical wave guide. In general, the cluster of cladding and optical core.

Fiber Amplifier
Amplifies an optical signal which passes through it.

Fiber Bandwidth
A frequency at which a specified fraction of the optical power at DC (0 frequency) is achieved. Typically, 0.5 is used as this value.

Fiber Buffer
A material that provides mechanical isolation between external influences and optical fibers in order to protect the fibers from physical damage.

Fiber Bundle
A bundle of unimpeded fiber optic cables used as a single transmission channel.

Fiber Optics
The technology of transmission of radiant energy through an optical medium made of glass or plastic.

FMC Conncector
FMC is an acronym for Flexible Microstrip Connector. This type of connector is very small and uses repeatable electrical characteristics to compensate misalignments. It is also used on the tightest spaces of PCB applications.

FME Connector
A connector designed specifically for use in cellular applications in vehicles, due to their compact size and convenient connection properties. They operate at frequencies up to 3 GHz.

The layout of the circuits on a board which is used in order properly connect components

Fourier Analysis
The process in which the equation of a complex wave is separated into parts of component wave, each having a certain phase displacement, amplitude, and frequency.

Free Space Impedance
In a vacuum, free space impedance represents the ratio of electrical to magnetic field strength for a plane wave. Mathematically, it is the relationship two-wire lines equation.

The number of cycles of a periodic activity per unit time. The typical measurement is Hz (Hertz), which is cycles per second.

Frequency Modulation (FM)
A method in which the amplitude of a signal remains the same while the frequency of the signal is modulated. Higher frequencies represent higher amplitudes in the original signal.

Fresnel Reflection
Loss due to reflection caused by the difference in refractive indexes between the output face and the receiving optical material.

Ratio between output and input power of an amplifier, antenna, or other device measured in decibels.

Gain Compression Point
The point in amplifier power at which gain is no longer linear.

Gallium Arsenide (GaAs)
A compound of the elements gallium and arsenic. It is often used to make devices such as laser diodes, solar cells, and microwave frequency integrated circuits.

Gaussian Filter
Filters that have no overshoot when the input is a step function and minimizes rise/fall time.

A unit of measurement denoting the number of cycles in one second. One GHz is one billion cycles every second. 

Global System for Mobile Communications (GSM)
The standard that describes protocols for 2G cellular networks. This was created by the European Telecommunications Standards Institute (ETSI).

Graded-index Fiber
A type of optical fiber that contains a refractive index, which gradually changes from the edge to the center. Compared to step-index fiber, graded-index fiber has much less dispersion.

Voltages in a circuit are measured in relation to a reference point, called ground.

Group Delay
The time delay for a signal to pass through a device.

Guide Pin
A protruding pin whose purpose is to guide two connectors in order to facilitate proper mating of the two halves.

A signal  in which the frequency is some integer multiple of a reference signal's frequency.

Heat Shock
A test in which a sudden, high temperature change takes place on a material for a short period of time in order to determine its stability.

Heat Shrink
A plastic tube that is typically made of polyolefin or nylon, that is used as a booting on a cable assembly. When heat is applied to the heat shrink material, it 'shrinks' in size to provide a snug jacket at the base of the coaxial connector and cable termination. Heat shrink provides added durability and ruggedness to the cable assembly.

Heat Treating
A set of methods using specific heat and tools whose goal is to change the properties of metals so as to improve certain characteristics.

The standard unit for electrical inductance.

Hermaphroditic Connector
A connector which has identical mating faces. There are no gender-specific members.

Hermaphroditic Contacts
When contacts contain mating components that are exactly the same at their mating face, they are known as hermaphroditic contacts.

Hermetic Seal
An airtight seal commonly found on critically sensitive electronic components. This seal protects against the flow of gasses, liquids and other foreign matter.

Hertz (Hz)
A frequency unit equal to one cycle per second. 1 Hz = 1/sec. The name Hertz comes from Heinrich Hertz, the German physicist that discovered the existence of electromagnetic waves in the 19th century.

High-Pass Filter
A HPF allows higher frequencies to pass, while rejecting lower frequencies; the opposite of a lower-pass filter.

HN (High Voltage N) Connector
A high-voltage application version of the popular N connector. A high-strength dielectric is used, as well as structural properties that ensure the outer conductor connects before the inner connector.

HV 4-10 (High Voltage C) Connector
A type of coaxial connector contains a bayonet coupling mechanism. Although similar to a C connector, an HV 4-10 connector cannot mate with a C connector. It has fast and reliable connection and disconnection due to its 2 pin bayonet locking system, and has high dielectric strength because of a layout of overlapped dielectric in the connection area. The inner contacts are always closed after the outer contacts. HV 4-10 (High Voltage C) connectors are typically used for high-voltage applications, such as Geiger-Muller counter tubes.

Hybrid Coupler
A 4 port coupler that splits the input signal equally, and as a result, shifts the signal 90 degrees between output signals. It is also capable of combining signals while preserving high isolation between them.

IEC Antenna Connectors DIN 45325
A snap-in coaxial connector for IEC antenna's which is capable of transmitting frequencies at max of 1GHz

An acronym for Institute of Electrical and Electronics Engineers. IEEE sets many of the standards in the fields of electronics.

IEEE 802.11
The set of standards used for the design and implementation of wireless LAN

A ratio of the current and voltage phases of a component. Impedance changes with frequency. When selecting which type of connector to use, the connectors impedance must match the impedance of the system being used.

Impedance Matching
A condition in which the internal impedance of a source or the surge impedance of a transmission line is the same as the impedance of a component or circuit, which gives minimum reflection and distortion, as well as maximum energy transfer from the source to the load.

The property of glass bodies referring to impurities.

Incoherent Light
Light rays that are not emitted with the same phase angle.

Indicators are used to monitor the state of switches in an RF system.

Wavelengths are shorter than 1 mm and longer than 700 nm. They can be felt as heat, but cannot be seen by the human eye.

Injection Laser Diode
See: Diode Laser

Insert Coax 0.8-2.7 (75 Ohms)
Inserts designed for DIN-Hybrid connections. They have a maximum operating frequency of about 1.5 GHz, and offer great mechanical and electrical stability, as well as a small profile for applications where space is limited.

Insert Coax 1.0-2.3 DIN
A smaller version of a coaxial insert for DIN-Hybrid connectors, typically used with mixed card edge connectors. They have very good electrical stability and have a maximum operating frequency of about 2 GHz.

Insert High Voltage DIN
Miniature connector inserts for DIN hybrid connections. This type of insert is very small, thus requiring very low space, and allowing applications in tight layouts in all types of electronic devices. They also have electrical and mechanical stability, and are made for use in mixed card edge connections. Female contacts are made from high quality beryllium copper, while male connectors are made with a plastic body.

Insert Mini Coax
A smaller version of a coax connector for hybrid connections for use in limited-space applications, with a maximum operating frequency of about 6 GHz.

Insertion Loss 
Insertion loss is the loss of power caused by having a switch located between two connectors in the transmission. It is measured in decibels (dB). All RF/Microwave devices have insertion loss > 0.

Material used to prevent or impede the flow of current, also known as dielectric in certain applications.

Insulation Resistance
The electrical resistance of a material which insulates in specific conditions between any pair of conductors, contacts, or grounding device in different combinations.

Materials with very high resistance, insulators includes glass, plastic, rubber etc…

A connection between two components which joins and completes electric circuits.

A multiple-contact connector has two surfaces on the contact side of both of its halves, which face each other during the assembly of the connector. These two surfaces are called the interface.

The process in which the amplitudes of multiple waves are systematically weakened and reinforced. Also, the process in which one wave is divided into two or more waves, then joined again back into a single wave.

Intermediate Frequency
The frequency in which a carrier frequency is converted to during the process of transmission.

Known as the International Standards Organization. This organization develops standardized methodologies which are used worldwide.

A metric describing the quality of separation between signals at adjacent ports. The higher the isolation value, in dB, the less interference exists.

A ferromagnetic passive device containing two ports which utilizes an internal resistor and controls the direction of signal flow. Other RF components are protected from excessive signal reflection by the isolator.

A protective cover present on the outside of a cable. The jacket should be insulating if insulation does not already exist.

K band
Frequency range between 18 GHz to 27 GHz. IEEE Standard 521-1984

Ka band
An IEEE standard concerning frequencies from 27 to 40 GHz

SI unit prefix meaning 1000 times the unit it is attached to. Example: 1 kilogram = 1000 grams.

Ku band
Frequencies between 12 and 18 GHz as specifies by IEEE Standard 521-1984

L band
The frequency band from 1-2 GHz. IEEE Standard 521-1984.

Land mobile radio (LMR)
Vehicle mounted or human-portable wireless communication systems for land transportation.

May refer to either a narrow band of coherent light, or the source of that light. The name is derived from an acronym, "Light Amplification by Stimulated Emission of Radiation."

Launch Angle
The difference in angle between an optical fiber's axis and the light ray's angle.

A device whose goal is to reduce the input power so that certain components are not damaged.

Limiting Level
Input power level at which gain is no longer linear. See "Gain Compression Point."

Line Impedance
The impedance of a transmission line as measured via the its terminals.

Line Transformer
Transformation properties owned by transmission lines which depend on the length of the line.

Linear Phase Filter
Simply put, a phase filter whose curve is linear, and whose time delay is constant.

Linear Phase Response
A linear relationship between change in phase angle per unit of frequency.

The temperature at which a solder melts.

Loaded Q (Working Q)
The ratio of the center frequency to the 3dB bandwidth of a bandpass filter.

Low Noise Block (LNB)
A low noise block takes the small signals it receives from the dish and amplifies the signal to a usable level and converts the signals.

Low Noise Cable
Mechanical movements can cause spurious electrical disturbances. A low noise cable is designed to prevent these disturbances.

Low-Pass Filter
This type of filter lets lower frequencies pass while rejecting higher frequencies. It is the opposite of a high-pass filter.

An acronym for Low Smoke Zero Halogen.

Macro-bending loss
When fiber bends are greater than its diameter, the critical angle becomes greater than the incident angle, causing light rays to exit a wave guide and resulting in light loss, or macro bending loss. This does not cause radiation loss.

Invented by Albert Wallace Hull, the magnetron is a high-powered vacuum tube that works as microwave oscillator. The strong magnetic fields produced by the magnetron produce the high-power output required in radar equipment. It enabled airborne radar at microwave frequencies during WWII.

MCX Connector
Micro-miniature Coaxial Connectors are made to be very reliable, easy to mount, and very small, containing a snap-on connecting system and used for frequencies up to 6 GHz.

Measurement Line
In RF, this refers to the transmission line whose field distribution is sampled.

In the SI system, a prefix that means one million (1 x 10^6). Its abbreviation is M. 1 MHz = 1 x 10^6 Hz.

Megahertz (MHz)
Equal to 1 million Hz. Uses the SI Prefix Mega, meaning 10^6.

Meridional Ray
Ray passing through the axis of an optical fiber.

The SI prefix meaning 10^-6. Abbreviated by the Greek letter "mu" (?).

Microbending Loss
In an optical fiber, sharp curvatures that involve spatial wavelengths of a few millimeters and local axial displacements of a few micrometers may cause light loss, or micro bending loss. These bends may be caused by packaging, installation, fiber coating, and cables. Micro bending can cause mode coupling and significant radiation losses.

Connectors with high contact quality and screw-lock system for high stability and shielding. For use  with low noise cables.

A micrometer (?m) is a unit of length in the SI system. 1 ?m = 1 x 10^-6 meters.

Microstripline is a type of transmission line that has a solid ground plane metallization and a metalized strip, which is separated by a solid, thin dielectric. It is commonly used on PC board and ceramic substrates in the range of 400 MHz to 6 GHz since it allows transmission lines to be manufactured accurately. Stripline technology is often used for broadband devices or higher frequencies.

A section of the electromagnetic spectrum extending between 1 and 300 GHz. The microwave spectrum is between the RF and infrared spectrums, and is used in many applications, including communications.

An abbreviation for the word "military." Often appears as "MIL-SPEC," implying that a part meets military specifications.

Milli (m) is a prefix in the SI system, which means one thousandth (1 x 10^-3). For example, 1 mm = 1 x 10^-3 m.

Mini SMP Connector
The smallest connector on the market, with operating frequencies up to 65 GHz and an impedance of 50 Ohms.

Mini UHF Connector
A type of miniature coaxial connector with an impedance of 50 Ohms and improved electrical performance compared to normal UHF series connectors. It is fitted with notched edges for adjustment and the typical UHF screw-locking system. Also, this connector has a high vibration security and torsional protection, which are provided by lugs located on the plug, corresponding to the notched edges on the jack. Mini UHF connectors are commonly used in mobile devices that perform up to 2.5 GHz.

Mismatch (Connector Impedance or Line Impedance)
The event when the load and the source do not have the same impedance. This results in reflection and loss of power.

A line is mismatched if its characteristic impedance is different from its termination resistance. This often causes reflections, which lead to undesirable losses.

MMBX Connector
A Micro-Miniature Board connector is used for "sandwich" and vertical direct Board-to-board interconnection. It is typically used for applications from DC to 6 GHz, and has an impedance of 50 Ohms.

MMCX Connector
Stands for Micro Miniature Coaxial connector which have snap on connection and can have frequencies from DC up to 6GHz. 

Modal Noise
When a coherent light source is used, there is noise generated at the wave guide's exit aperture. This effect, called modal noise, is caused by modal interference in the wave guide. Also see: Mode, Interference.

An electromagnetic field distribution that satisfies boundary conditions as well as Maxwell's equations in a transmission line or cavity. Dependencies of a mode's field pattern include wave guide geometry, refractive index, cavity, and wavelength. Also see: Equilibrium Mode Distribution.

Mode Coupling
Describes the exchange of signal power in an optical fiber among modes, which eventually approaches some equilibrium.

Modification of a signal created by super imposing the data signal onto a carrier frequency.

An electronic device the takes in a baseband signal as input and converts it to a modulated RF signal.

Moisture Resistance
A materials ability to not absorb or resist the absorption of water.

MTBF – (Mean Time Between Failure)
The average time between the occurrence of failures in a component.

Multimode Fiber
A type of fiber that allows more than one mode to propagate. The number of modes in a fiber is determined by Maxwell's equations and boundary conditions. The multimode fiber's core diameter can range from 25-2,000 microns.

Multiple Reflections
Multiple reflection waves are caused by continuous new reflections which are the result of propagated waves that are repeatedly reflected both at the input and the output ends of a transmission line. These reflected waves superimpose themselves on the primary waves.

A network or device that receives multiple signals through its input, and outputs the signals separately, according to their frequency.

Multiplier Nonlinearity
A frequency multiplier has an output power that is proportional to the squared input power. This condition is called a "square-law" curve. Its power transfer characteristic is very different from an amplifier, limiter, or mixer.

N (50 Ohms) Connector
Coaxial connectors capable of frequencies up to 12 GHz. They have screw locking system and are reliable.

A length equal to one billionth of a meter.

Random fluctuations of electrical signals caused by natural disturbances or circuit components.

Noise Currents
Refers to any noise that inhibits the ability to take accurate measurements.

Noise Equivalent Power (NEP)
The point at which the rms of the optical power compared to the rms noise results in a signal to noise ration of 1.

Noise Temperature
Noise temperature is the amount of thermal noise found in components. In electronics, it is a way of expressing the total level of available noise power introduced by a component or power source.

No-load Impedance
Input impedance when no load is present.

Non-unilateral Device
A non-unilateral devise is active component such as an amplifier with poor directivity.

Numerical Aperture (NA)
The value that describe the ability of a fiber to accept light. Generally speaking, a higher value is more desirable.

Omnidirectional Antenna
Ideally, it is an antenna that is capable of radiating in all directions on the horizontal plane.

Operating Mode 
When the actuating voltage is removed, the characteristic that decides the operation of the switch is called the operating mode.

Operating Mode-Latching 
In latching mode, the RLC switch will remain in any switched position when the actuating voltage is removed. This mode is optional on my RLC switches. In many standard RLC latching switches, the actuating current is automatically cut after the switch has changed position due to its "Cutthroat" solid state circuit.

Optical Waveguide
Any structure capable of carrying the radiant energy along a path along its axis.

A branch of study whose focus is light in the context of electronics. This includes LEDs, Lasers, photo sensors or any devices the utilize optics/light.

An electronic testing equipment use in the analysis of waveforms. From an oscilloscope, one can gather data about the shape of the waveform, it's frequency, distortion, rise-time, etc.

In a printed circuit board, the metal portion in which the leads located on a surface mount component are mated is called the pad. It is also known as a land or footprint.

The frequency range for a filter that does not get rejected.

Passive Device,
A device with no power source. A passive device cannot add energy to a signal

Passive Intermodulation (PIM)
Occurs in passive devices such as cables or antennas that are subjected to two or more high power tones. PIM is the result of multiple tones mixing. The higher the signal amplitudes, the more pronounced the effect of PIM.

Peak Sidelobe Ratio
Ratio between the highest side lobe intensity to the intensity of the beam parallel the azimuth of an antenna.

A measure of the amount of resistance that results when creating an electric field throughout a medium. It describes how an electrical field affects a medium.

In electronic signals, phase is defined as the position of a point in time on a waveform cycle. A complete cycle is defined as 360 degrees of phase.

Phase Balance
Given a frequency range, it is the max peak-to-peak difference in phases of power divider output ports.

Phase Detector
A device that outputs a DC voltage proportional to the phase difference between two RF input signals.

Phase Distortion
A distortion caused by non-linearity in the phase-response.

Phase Jitter
The undesired variation in the phase from its desired level

Phase Modulation
A method of encoding data onto an AC waveform by varying the instantaneous phase of the wave.

Phase Noise
The representation of random fluctuations in a waveform's phase as a frequency domain.

Phase Shift
After a current or voltage passes through a cable or circuit, any change in its phase is called the phase shift.

Phase Shifter
Device used to shift the phase of a signal, ideally with very low insertion loss and amplitude output that is equal on all phase states.

Phase Stability
Change in electrical length in a cable based on changes in temperature and other parameters.

PIM (Passive Intermodulation)
A nonlinear response from a passive device caused by inconsistencies or impurities in the materials or connections. This is seen when there are two or more signals in the device.

Pin Contact
A type of male contact designed to mate with a socket or female contact.

Plastic clad silica (PCS) fiber
High quality fiber optic cable with high light transmission, made with a glass core and plastic cladding.

Plated Through-Hole
A hole into which components can be soldered into place in order to connect them to other circuit components.

A property of electromagnetic waves which describes its orientation in space. Polarization is dependent on the type of wave, the type of source, and the source's orientation.

Power (Average)
The average power of a signal

Printed Circuit Board (PCB)
A PCB, or PC Board, is a composite of multiple materials like metal, epoxy glass, silicon, copper and non-conductive substrate. Hardware such as passive and active components can be attached to transmit signals and data. Circuits are also etched onto the PCB.

Propagation Constant
The longitudinal wave propagation along a conductor is represented by the propagation constant. Along with the characteristic impedance, it enables the calculation of the transformation characteristics of the current and voltage on the conductor, as well as their distribution.

Propagation Delay
A transmission network or digital device requires an amount of time to transfer information from its input to its output. This is known as propagation delay.

A pre-production model of a product that exhibits full or partial functionality of the final product.

PTFE (PolyTetraFluoroEthylene)
PTFE has a stable and low dielectric constant and loss factor over a broad frequency and temperature range. Therefore, it is used as an insulator in microwave and RF coaxial connectors.

A brief change in value, usually voltage in the positive direction, that returns to the steady state.

Pulse Width
The amount of time wherein an electrical pulse is transient.

Relationship between the change in frequency per unit voltage changed.

The Q is a measure of a filter's frequency selectivity or sharpness of response. It is also known as the figure merit of a filter.

A subminiature connector using a quick latch coupling connection and whose resistance is 50 ohms.

QMA Connector
A QMA connector is based on the dimensions of an SMA connector, however, it contains a snap-lock mechanism rather than a threaded coupling mechanism. It has frequency range DC - 18 GHz.

QN Connector
Connector with a snap-lock mating mechanism based on N dimension

Quantum Efficiency
A factor of efficiency calculated using the conversion between photon/second and electrons/second for a light sources and detectors.

A connector that allows for quick connecting/disconnecting.

A type of adapter that is used for test applications since it enables quick connection and disconnection. It can be plugged without the need of a coupling nut.

The basic element in an antenna that actually emits a signal.

Radio Frequency (RF)
Electromagnetic energy emitted between 50 MHz to 1 GHz

Rated Voltage
Maximum voltage that can be constantly applied to a cable, connector, or any electrical component without destroying the component or causing any permanent alterations to its technical parameters.

Pictorial representation of the path which a light wave travels.

Rayleigh Scattering
Scattering by index fluctuations that are both refractive and small in relation to wavelength. The fourth power of the wavelength is inversely proportional to the scattered field.

Reactive Splitter
A device that divides power equally on the input onto several output ports. This is done without much change in the phase relationship and causes little distortion.

Any device that receives and interprets an optical signal into an electrical or digital one for use by other devices.

A two-piece multiple contact connector's stationary half. It also commonly has socket contacts and is mounted on a panel.

An antenna works in exactly the same manner in receiving the signal as it does when sending a signal.

Reentrant Modes
Reentrant modes occur when a band-pass filter is designed for one frequency, but it also passes RF at integer multiples of the intended frequency.

The return of waveform after bouncing on an object. This is sometimes used as a metric of inefficiency for cables and other devices when referring to internal reflection.

Reflection Loss
When power is reflected at a line discontinuity, part of a signal is lost. This is known as reflection loss.

When oblique incident rays pass a medium that has a certain refractive index into another medium with a different refractive index, the rays will bend. This is known as refraction.

Refractive index
A number that indicates how much light will bend when it enters a medium. It a ratio of the speed of light in a vacuum over the speed of light in the given medium. 

Relative Attenuation
Attenuation relative to the minimum.

The ratio of output to input (gain) of a detector system. Standard units of measurement are amps per watt.

Return Loss
The measure of the amount of reflected power when it is connected to any active or passive device or terminated on a transmission line. Return loss can be used to calculate VSWR and the Reflection Coefficient Expressed in dB.

Return Loss (from Reflection Coefficient)
Loss from reflection due to scattering, measured in dB, measured by taking the logarithm of the reflection coefficient and multiplying by -20.

RF (Radio Frequency)
Frequencies typically ranging between 50 - 999 MHz where radiation of electromagnetic energy is possible. Microwave frequency is considered to be 1,000 MHz (1 GHz) and up.

RF Choke
A component that allows low frequency or DC to pass through, but blocks RF signals.

RF Leakage
An amount of a signal that is lost in (or radiated by) a connector.

RF Mixer
A device that translates frequency from the input signal to the output signal. When a mixer is used for up-conversion, the input is an IF signal and the output is an RF signal. It is the opposite for down-conversion.

RF Shielding
The process of blocking an electromagnetic field with magnetic or conductive barriers in order to suppress it.

When a transient waveform is applied to a filter, it may tend to oscillate for a period of time. This is known as ringing.

Sinusoidal changes in the amplitude response of a particular filter.

Rise Time
The amount of time a signal takes to get from its steady state to some peak value. It is the opposite of fall time.

Restriction of Hazardous Substances discusses the amount of particular materials that may be used in electronic devices.

Root Mean Square
A mathematical operation done to a set of values. Specifically, it means "the square-root of the mean of the squared values." This has many applications in electrical engineering, including the calculation of average power.

Rubber Duck Antenna
An electrically short monopole antenna that is protected by a plastic or rubber jacket. Its function is similar to a base-loaded whip antenna.

S band
S band is a band of frequency between 2 - 4 GHz; IEEE Standard 521-1984.

Screening Effectiveness
The ratio of the input power to a coaxial cable to the power transmitted by it and outputted by the outer conductor.

Screw Machine Contact
Solid bar stock is used to machine this type of contact.

Self Alignment
A phenomenon caused by surface tension of liquid solder, which occurs when leads align themselves on solder pads.

A substance that has resistance between that of a metal conductor and an insulator. Silicon is an example of a highly used semiconductor.

Cables whose outer insulators are relatively rigid, while the inner conductor are more flexible. This allows the cable to be more rigid but still be marginally flexible.

The input power level which is required for the system to operate as intended.

Shape Factor
The ratio of Attenuation Bandwidth to 3db bandwidth for a bandpass filter, 3dB Bandwidth to Attenuation Bandwidth for a band-stop filter, Attenuation Frequency to Fco for a low pass filter and Fco to Attenuation Frequency for high pass filter.

Shape Factor (Bandwidth Ratio)
The ratio between High and low attenuation level bandwidth or between 3dB Bandwidth to the stop band bandwidth

SHF = Super High Frequency, Range: 3GHz to 30GHz

A conducting screen or housing that greatly reduces the effect of magnetic or electric fields coming from one side onto any circuits or devices on the other side. Cable shields can be taped, braided, or solid. Also, the metallic layer in a cable that prevents electromagnetic or electrostatic interference between the external fields and enclosed wires. This metallic layer is placed around a conductor, or group of conductors.

A metallic coating used to prevent signal interference or current leakage in a circuit or coaxial cable.

Sine Wave
The classic example of a "wave." A sine wave is a function whose value oscillates about some zero value equally in both the positive and negative directions with respect to time.

Single-mode Fiber
An optical fiber whose diameter is so small that light can only travel on one path. This dimension must be under 10 microns.

Skin Effect
The tendency for an AC signal to be present at the surface of a conductor rather than in the interior. This property is due to the natural gathering of charge at the edges of a conductor.

SMA Reverse Polarity
Sub-Miniature coaxial connector with a center contact with reversed gender. They perform up to 18 GHz and are often used for connections between W-LAN components, and have optimum electrical properties, such as low VSWR, high durability, long life, and high mechanical stability.

SMB (Subminiature B) Connector
A coaxial connector capable of frequencies from DC to 4GHz. Uses snap on coupling.

SMB Connector
A subminiature connector with a simple snap-on mechanism, and a maximum operating frequency of up to 4 GHz.

SMC Connector
A connector with a screw-on attachment, usable up to 10 GHz. These connectors can be coupled with a shared nut.

Smith Chart
Used to calculate resistance transformations on transmission lines, as well as the corresponding matching circuits. A Smith Chart represents the reflection coefficient as a complex plane within the restrictions of the unit circle. It contains lines of complex resistances that are normalized respectively to the characteristic impedance, consisting of constant real components and constant imaginary components.

SMP Connector
A micro-miniature connector most commonly used in board-to-board applications. They operate up to 40 GHz and are available in a variety of mounting styles.

SMS Connector
A subminiature connector with a slide-on coupling mechanism and has a frequency range of DC - 4 GHz

Snap N Connector
A quick-lock connector that can be mated with an N connector. It can be connected very quickly and in tight places without the need of any tools.

The ability to easily assemble or remove one part to or from another

Solder Paste
A combination of several components including, solder powder, flux, solvent, and binder. It is printed onto PCB's and used to form solder joints.

The process of connecting many components by melting a metal which holds them together.

Spectrum Analyzer
An instrument that measures the amplitude of a signal along a range of frequencies.

A splice is a permanent junction, either applied mechanically or fused thermally, located between optical fibers.

Spread Spectrum
Spread-spectrum techniques give a signal a wider bandwidth by spreading its original bandwidth in the frequency domain.

Spring-Finger Action
A contact locking mechanism that uses a small protrusion, angled away from the direction of connection, to lock a connector into place.

Spurious Free Dynamic Range
The ratio between the RMS power of the fundamental signal and the RMS power of the resulting noise or distortion.

SSMC Connector
A micro miniature coaxial connector capable of 6GHz frequencies and has low voltage standing wave ratios. The connector uses screw on coupling.

When two sets of waves travel in opposite directions, the resulting distribution of voltage and current on a transmission line is called standing-wave.

Star Coupler
A passive electrical component which takes multiple optical inputs and spreads their power along multiple outputs.  

Step Function
A signal with instantaneous change in amplitude, shaped like a step. Typically, step functions are used to test transient responses for systems.

A range of frequencies that are rejected - typically by a filter.

A type of transmission line with a conducting strip either on top of or between two conducting surfaces (typically, stripline refers to the latter). It is generally favored in higher frequencies and broadband applications.

It is a plating material with Nickel-Phosphorus-Alloy under a layer of gold. Provides protection from wear and excellent solder-ability.

Super Conductor
Has a bulk resistivity of zero.

Surface Mount Device (SMD)
A passive or active device that is made to be soldered onto a PCB surface.

Surface Mount Technology (SMT)
A way of mounting components to the surface of a printed surface board as opposed to plated through-holes.

TEM Wave
TEM waves, or Transverse Electro-Magnetic waves have magnetic and electrical field parts that lie on a plane that is vertical to the direction of propagation. These waves can propagate on coaxial lines.

A temperature range (minimum through maximum) at which a component can function while still meeting all its required specifications.

Termination (RF Load)
A component that absorbs the remainder of a signal, ideally with little to no reflection.

Test Voltage
The maximum voltage in which a circuit component can be used for a specific amount of time, and under specific environmental conditions, without getting damaged.

Time Delay
For a signal to pass through a filter, it will take a certain amount of time. This is known as time delay.

TNC (50 Ohms) Connector
Coaxial connectors with electrical properties and dimensions similar to a BMC connector, but with a screw-on mating mechanism for quick connections. It generally usable up to 4 GHz.

TNC Reverse Polarity Connector
A type of threaded coaxial connector that contains the opposite sex center contact. This is know as reverse center contact. Optimum results are achieved up to 4 GHz, and is often used for connections between W-LAN components, much like SMA reverse polarity connectors.

Total Internal Reflection
The confinement of light by means of reflection within a substance. This is the property that allows optical fibers to transmit light with no loss.

A component capable of both transmitting and receiving signals. In the RF sphere, it's implementation is used to tighten the gap between digital signals and antennas.

Converts energy from one form to another. For example, electrical energy (audio-frequency) into sound.

Transfer Impedance
A value relating the current in the outer conductor of a coaxial cable to the voltage drop between the outer and inner sides of that conductor. The impermeability of the outer conductor of coaxial cables is represented by the transfer impedance.

Used to achieve maximum power transfer by matching impedance, as well as for separating DC from two circuits while keeping AC continuous, and voltage step-down or step-up. These processes take place in low-power electronic circuits.

Transmission Coefficient
The measurement of the degree of a signal's transmission that goes through a network with two ports. In other words, it is the ratio of the amplitude of the transmitted wave to the wave at the two port network input.

Transmission Line
Refers to the group signal carrying components, like a waveguide, a Stripline, or a coax, in a circuit.

The ratio of the radiant power let through to the total radiant power.

A device that transmits an electrical signal over a fiber cable by first converting it into an optical wave.

Triaxial Cable
A type of cable similar to the coaxial cable, but has two outer concentric conductors, an insulating layer between them, and a center conductor.

A passive device that will split a complex signal into three pre-defined frequency bands.

TTL Control Circuit
A Transistor-Transistor Logic Control Circuit allows the user to control switch operations with a 5 volt control circuit.

Twinax BNC
Di-Pole symmetrical connectors with a bayonet coupling mechanism, applicable for shielded twin-wire cables with different characteristic impedance. It is not mateable with standard BNC connectors.

Twinaxial Cable
A twinaxial cable (Twinax) has two-pole symmetrical connectors which are polarized and locked. It also has a screw-locking system and gaskets that make it weatherproof. Twinaxial cable has impedances between 75 and 95 Ohms.

Two-Wire Line
A two-wire line has two separate conductors that are mutually insulated. It is the most common type of electrical cable.

An acronym for Uniform Circular Array, which is an arrangement of antennas in a circular formation, equally spaced apart.

An arrangement of antennas in a grid pattern, where they are spaced equally apart in both dimensions

A Uniform Linear Array is a collection of transmitters aligned with equal spacing in a linear fashion.

Ultra Wideband (UWB)
Useful at low energy levels and short ranges for high bandwidth communications. This technology uses a large frequency range.

A spectrum of light that is outside the visible spectrum that ranges from 20 to 380nm and is damaging to human eyes and skin.

Unilateral Device,
Unilateral devices usually refer to ideal amplifiers and other active devices where the parameter S12 = 0. This is an idyllic concept.

V band
A frequency band between 40-75 GHz. IEEE Standard 521-1984.

Vapor Phase Soldering
A soldering process, during which the heating method uses of latent heat of vaporized liquid.

Vector Network Analyzer (VNA)
An instrument that measures an electrical network's parameters, such as S, Y, Z, and H parameters.

Vector Signal Analyzer
A electromagnetic analysis device which measures of the magnitude and phase of an input signal to produce data such as spectral flatness and error vector magnitude.

Velocity of light
In a vacuum, the speed of light is approximately 300,000 km/s (186,000 miles/sec)

Velocity of propagation (VoP)
The possible speed of an electrical signal in a medium relative to it's speed in free space. Velocity of Propagation is usually expressed as a percentage.

An acronym for Very High Frequency, which is from 30-300 MHz

Voltage Controlled Oscillator (VCO)
An oscillator that can change the frequency by supplying a voltage to it.

Voltage Standing Wave Ratio (VSWR)
The measurement of how efficiently radio frequency is transmitted from a power source to a load through a transmission line. A VSWR of 1 is ideal. From VSWR, Return Loss and Reflection Coefficient can be calculated.

VoP (Velocity of propagation)
The speed of an electrical signal, expressed as a percentage, when it travels through a cable in comparison to speed in free space.

Voltage Standing Wave Ratio. VSWR is a measurement of signal reflection in devices, with a VSWR of 1 being ideal (no signal reflected. VSWR can be converted to return loss or the reflection coefficient.

W band
Frequency band between 75 and 110 GHz, from IEEE Standard 521-1984.

Wave Soldering
A largely used process for through -hole boards, solder is applied to the bottom of the board and connects the metal surfaces.

Hollow tubes with conductive walls which transmit signals along its axis. Waveguides can be rectangular, circular, or elliptical, and the operating frequencies are dependent on its shape and dimensions.

The distance from the beginning of an electromagnetic wave's complete cycle to the end of the cycle. The distance over which the wave's shape repeats.

The process of joining to metals through a very high temperature procedure.

Wilkinson Power Divider
A passive device that either combines input signals to a common port or divides an input signal between its outputs. However, power dissipation limits the power divider when it is used as a combiner. Power dissipation occurs when signals are non-coherent, out of phase, or have amplitude imbalance.

X band
Frequency range between 8 GHz to12 GHz. IEEE Standard 521-1984

A directional, shortwave antenna containing a group of dipoles that are equally insulated and are parallel with a horizontal conductor. Yagi's contain one or two dipoles that are connected with the receiver.

A method of short range data transmission used to create personal-use networks for connecting devices.

                                                                                   Back to Top