RF Technical Terms Dictionary

With this collection of engineering RF technical terms we hope to help you in finding the best explanation for the technical challenge you have now.

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


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


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.

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, 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, 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. The effect of noise is reduced by the gain of the LNA, while the noise of the LNA itself is injected directly into the received signal.

Amplifier, Maximum Signal Level of
a threshold for which the greatest CW or pulse RF signal can be used without permanent noise figure degradation, amplified distortion, amplification reduction, and/or overheating of the amplifier.

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. Power is generally considered between 0.5 Watts up to 4 Watts. High Power amplifiers are designed for power above 4 Watts.

Amplifier, Pulsed
for an amplifier to be pulsed, it is electrically switched off when the signal is not being amplified. The majority of CW amplifiers are able to be used as pulsed amplifiers but not the other way around. The pulsing of an amplifier results in cooler operating temperatures by the reduction of DC power dissipation. In this way, pulse amplifiers can be run at higher power. Due to this design, continuously powered amp will cause damage from heat. Therefore, the magnitude of duty cycle will directly affect the temperature of the amp. These devices need special power supplies to provide DC bias point during its duty cycle. One feature of these power supplies often require large storage capacitors. The amp bandwidth should be taken into consideration for very short pulses.

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

Amplifier, Return Loss (RL)
Return loss (RL) describes reflected-to-incident power ratio at an RF port of an amplifier. Expressed as RL = -20 log |?|, ? = voltage reflection coefficient and RL is in units of dB.

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

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 tracking
difference in amplitude between a test filter and a reference filter.

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

Angle of Incidence
angle measured from the angle perpendicular to the surface and the angle of the ray of light that strikes the surface.

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

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

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

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 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.

used in the extension of dynamic range of devices like power meters and amplifiers, this device transmits an input signal with minimal distortion by absorbing part of the signal itself. The attenuator is also used as a way to equalize signal levels in transmission lines.

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, 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.


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.

Barrel Adapter
a two ended, male-to-male adapter for various connector types.

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

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.

Bi-directional Coupler
a single coupler that doesn’t terminate internally, this 4-port coupler allows the forward and reflected signals to be sampled at the same time.

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 Reverse Polarity Connector
the non-standardized versions of common BNC connectors, these coaxial connectors operate up to 4GHz. While being similar to standard BNC connectors, the center contacts are reversed and the dielectric may be reversed as well. For instance, a male polarity connector using a female center contact and dielectric and visa versa. The purpose and application of this type of connector is regulated by IEEE/FCC. The type with bayonet coupling mechanism have a max frequency up to 10GHz (optimum at 4GHz) with characteristic impedances of Z=50 Ohms. The bayonet design allows for quick and dependable connections and disconnections.

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

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.

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.

Bullet Adapter
a two ended, female-to-female adapter for various connector types.

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.

Butterworth Filter
this filter provides the flattest possible, monotonic response in its passband which rolls off consistently at 6dB per octave per pole.


C band  
used for long distance radio and telecommunications, IEEE standard C band frequencies operate between 4-8 GHz.

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

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

Capacitor, RF Bypass
an RF bypass parallel element that is meant to reflect RF signals by shorting them out. This filter uses microwave capacitors.

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.

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.

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

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.

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 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.

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

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.



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

DAS (Distributed Antenna System)
a network of separated antennas connected to a common source that provides wireless service within a geographic area or structure such as an office building or school campus.

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.



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).

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

Elliptic Filter
A signal processing filter that has equalized ripple behavior to stabilize a signal. The amount of ripple can be adjusted.

EMI Filter
Electromagnetic Interference Filter. Also known as “feedthroughs”, EMI filters prevent stray signals from creating noise in your design by using a low-pass filter in combination with shunt capacitance and series inductance.

End Launch
Refers to attaching a connector on the end of a printed circuit board.



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.

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.

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.

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.

Frequency Doubler
As the name implies, this non-linear device produces an output frequency that is twice the input.

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.

Frequency Sensitivity
Also known as “flatness”, frequency sensitivity describes the maximum peak-to-peak variation of a directional or hybrid coupler across a specified frequency range.



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.

Gallium Nitride (GaN)
A compound commonly used in light emitting diodes (LEDs)

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

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).

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



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

A type of coax cable that is spirally corrugated.

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

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

Hi-Pot Testing
It tests the maximum voltage and current of a cable.

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.



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.

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 Coax D-Sub
Small coaxial inserts for D-sub Hybrid Connections that have high electrical and mechanical stability. With a maximum operating frequency of 2 GHz, their small size are ideal for cramped layouts in various electronic devices and have applications in rack/plug-in chassis technology along with PCB.

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…

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

Usually undesirable in radio or audio processing, this is a process that modulates the amplitude of a signal containing two or more frequencies that have a non-linear relationship.

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.

Isotropic Radiator
Theoretically, this radiator emits electromagnetic radiation uniformly in every direction without loss of energy. In reality, a no-loss radiator does not exist as proved by the “hairy ball theorem”.



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

Local Area Network. A data communications network that exists only in a local area up to 6 miles or about 10 kilometers.

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.”

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 and Non-Linear Analysis
Testing devices in a simulation where the outcome is not dependent on whether power and voltage levels are linear. When power amplifiers and frequency conversion devices are tested, the simulation will require nonlinear analysis.

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.

Loaded Q (Working Q)
The ratio of the center frequency to the 3 dB 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.



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.

MHV Connector
Coaxial connector that uses bayonet coupling mechanism with a working voltage of 2.2kV DC.

This type of transmission line configuration is separated by a dielectric and uses a conductor over a parallel ground plane

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.

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 6 GHz.

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.

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.

N (75 Ohms) Connector
There are two versions of the N connectors: one with 50 Ohms and another with 75 Ohms impedance that cannot be mated. N connectors have a high degree of protection from weather with a screw locking system in medium dimension. They are robust, reliable and provide excellent intermodulation.

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 Figure / Noise Factor (Transducer)
The noise factor is described as the ratio of a/b where a is the available signal to noise(SNR) ratio. The ratio, a, is taken at the signal generator terminals when the temperature of the input is 290K and the bandwidth is restricted by a transducer. The b is the available SNR per unit bandwidth at the output terminals of the transducer.

Noise Floor
Noise floor refers to the lowest input power that produces a detectable output.

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.


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

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.

Provides an electrical signal that oscillates in voltage magnitude depending on the voltage input.


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

Passband Ripple
Attenuation of the signal within the passband that varies with frequency.

A type of finish for Stainless Steel parts.

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.

Permeability (magnetic)
The measure that compares how magnetic force lines travel through a material compared to air. Air is designated with a permeability of 1.

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 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.

Phase-locked Loop (PLL)
A process that keeps the phase of the input and output in step with each other.

Pig Tail
A cable assembly with only one connector attached. The opposite side of the assembly is unterminated or open-ended.

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.

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 (Peak)
Peak power rating usually specifies the low frequency or pulse energy of a signal, while the average power rating limits high-frequency operation.

Power Splitter
Delivers multiple output signals with phase and amplitude specifications. This is a passive device that takes in one input signal. Bidirectional splitters can combine signals as well. Also called power divider.

Primary Attenuation Step
The port of the step attenuator that is activated, or in the “high” state.

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.

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.



Q Factor
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



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

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.

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 Coefficient
Measured at the terminating resistance, the complex reflection coefficient is the ratio of the voltage returning from the load to the voltage supplied by the generator. From this, return loss and VSWR can be calculated.

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

Relative Attenuation
Attenuation relative to the minimum.

A module that receives an optical signal and converts it to an electronic signal while amplifying it and then re-transmitting in optical form.

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 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.

Denotes certain coaxial cables that are manufactured to Government Specification. For example, RG-58U: R represents radio frequency, G represents government, 58 is the number assigned to the government approval, and U represents universal specification.

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.

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

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.



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

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 3 dB. bandwidth for a bandpass filter, 3 dB 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 3 dB Bandwidth to the stop band bandwidth

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.

Short Circuit Impedance
The very small to non-existent impedance in a short circuit.

Shot Noise
Noise produced from the process of single electrons passing through the p-n junction. The mean square shot noise current is related to the diode’s average current and bandwidth. RMS shot noise = square root (2*q*I*B), where q is the elementary charge, I is current, and B is the bandwidth.

Undesirable gain response of an antenna in a direction not with the main beam.

Signal-to-noise ratio (SNR)
Signal power to noise power ratio which is related to bit error rate performance.

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.

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 Connector
Uses a 4.2mm diameter outer coax filled with PTFE dielectric. The upper frequency limit is between 18 to 26 GHz depending on the quality of manufacturing. Similar to many other coax connectors, a 5/16 inch wrench can be used to tighten the screw-coupling mechanism. These connectors are compatible with 3.5mm and 2.92mm connectors. There should be a careful inspection before mixing of SMA connectors that are more expensive.

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.

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.

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

SSMB Connector
Micro-miniature coaxial connector with snap-on coupling mechanism uses a tongue and groove design to hold the plugged connectors together. The design permits fast engagement/disengagement in small and hard to access locations.

SSMC Connector
A micro miniature coaxial connector capable of 6 GHz 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.

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



T Adapter
A 3-port device in the shape of a ‘T’ that divides one RF signal into multiples.

Time Delay Unit. This is a structure similar to a phase shifter and allows specific or programmable time delay using a multi-path structure. Unlike a phase shifter, TDUs do not provide a fixed insertion phase difference between two states. A TDU can provide a large number of wavelengths of phase shift which is exactly proportional to frequency such that the difference between group delays is flat over required bandwidth.

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.

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.

Transition Band
The frequency range between the passband and the stopband. This could be thought of as the “downward slope” between these two areas.

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.

Transmission Line Constants
The characteristic parameters of a transmission line

Transmission Loss
The loss of power from on point to another during propagation.

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

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.

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

A method use to attach the connector to the coax by twisting them together.


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.

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.

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.

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.

VSWR (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.

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.

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 to 12 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.

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