Glossary of Terms

This information is provided to help clarify and define the terminology associated with filters and their applications. Some of these terms are listed in the component datasheets. Many terms go beyond the specification of filters. These terms describe issues associated with filter design and performance, materials and theory and applications. A thorough understanding of these terms and definitions will aid in the selling, procurement and application of filter products.

Please also reference our Resources page for additional guidance on filter applications and technical guidelines.



1.85mm and 2.4mm Connector: Both 1.85mm and 2.4mm connectors are physically compatible and require 5/16″ wrench. They will not thread onto SMA, 3.5mm or 2.92mm 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 3 dB.

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.


Absorption: The loss of power resulting from conversion of power into heat.

Adapters: 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.

Alumina: 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%.

Aluminum: Material used as either a conductor or packing material. Symbol: AI, Atomic Number: 13.

Amplitude: Amplitude refers to a variation in value of 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 Match: The comparison between a reference filter and a filter being tested which analyzes the absolute difference of the amplitude response.

Amplitude Tracking: The relative difference in the amplitude response between a reference filter and a filter under test.

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

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

Attenuation: The reduction in signal power that occurs when a signal travels over long distances, measure in decibles (dB).

Attenuator: 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 attenuation is also used as a way to equalize signal levels in transmission lines.

AWG: (American Wire Gage) it is a unit of measure to measure thickness of solid wires.


Band Rejection Filter: see Notch Filter.

Band Ripple (Amax): The variation (error band) in he pass band response.

Bandpass Filter: A filter that passes a energy within a certain bandwidth and rejects frequencies above and below this bandwidth.

Bandwidth (BW): (1) The limits of a band of frequencies. In a bandpass filter these limits, or passband edges, are generally the frequencies at which -3dB of attenuation is measured, relative to the attenuation at the maximum transmission point of the passband. (2) The number of hertz expressing the difference between the upper -3dB frequency and the lower -3dB frequency of a bandpass filter (BW = F”-3dB – F’-3dB).
Bessel Filter: A filter network designed to exhibit constant time delay in its passband, without regard for amplitude response.

Bessel Filter: A filter network designed to exhibit constant time delay in its passband, without regard for amplitude response.

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

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.

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: A filter network that exhibits the flattest possible response in its passband. The response is monotonic, rolling off smoothly at the rate of 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.

Cable: 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.

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

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.

Case: The outer enclosure of the filter.
Please reference our Case Dimensions page for sizing and styles.

Center Frequency (F0): The midpoint of the bandpass filter passband, expressed as the arithmetic mean of the two -3dB frequencies.
F0 = (F’ + F”)/2

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 network that is designed to exhibit a predetermined passband ripple; in exchange, it provides more rapid attenuation about the cut-off (-3dB) frequency.

Coaxial Cable: A cable with an inner conductor surrounded by a flexible and tubular insulating layer; then surrounded by a tubular conducting shield.

Coaxial Connector: Typically used with coaxial cables, these connectors are designed to maintain shielding and minimize the change in transmission line impedance at the connection. An RF connector is an electrical connector designed to work at radio frequencies.

Conductive Emissions: Signals, unwanted (interference) or otherwise from a piece of equipment.

Conductive Interference: Interference transmitted along a conductor/cable.
Protection is provided by a series component. If a feedthrough filters is used to remove conducted interference, and mounted in the wall of a shielded compartment, it provides effective filtering while maintaining the screening integrity. It should be noted that the filter will reduce both emissions and susceptibility.

Connector: A fitting that is installed at the ends of fiber optic cables, light sources, receivers or housings. The connector mates to corresponding devices that also have installed fittings. For example, a connector can join two fiber optic cables and extend the light transmission.

Connector Gender: The gender of a connector can be male and female. Male connectors have a protruding connection, while the female connector has a crevice where the male connector can sit. There are some “sexless” connectors which can connect to any other sexless connector of the same type.

Contact: The part of an interconnect that interfaced between the connector and the lead or coaxial center conductor on the device being connected.

Contact Alignment: This defines the degree of loose fit which contacts are restricted to within the insert cavity so that mated contacts can still self-align. Also called the contact float.

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.

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

Cutoff Frequency (Fc): The frequency at which filters start to become effective.
The frequency that marks the edge of the filter’s passband and the beginning of the transition to the stopband, usually -3dB relative to the filter’s reference frequency.


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

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

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

DC Block: A capacitor that allows you to separate Direct Current (DC) voltages along a transmission line.

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.

Dielectric: In a coaxial cable, the dielectric is the insulation between the inner and outer conductor. Dielectric influences the electrical properties such as impedance and velocity.

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

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.

Diplexer or Duplexer: 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.

Dissipation: This is the energy loss in a filter that results from the non-ideal characteristics of its individual components, such as the resistivity in an inductor or capacitor, core saturation, resistance of connecting wires, and metal conductivity.

Distortion: Undesired changes int eh purity of a signal, so that a spurious element or elements are added. These changes can be exhibited as amplitude distortion (where the output does not bear the same proportion to the input at all frequencies) or phase distortion or non-linear phase shift.

DWV: The lowest voltage level that a conducting material can withstand.

Dynamic Range: The difference between the overload level and the minimum acceptable signal level, expressed in dB.


Electromagnetic Compatibility (EMC): A situation wherein two pieces of electrical or electronic equipment are able to function in the same environment without adversely affecting, or being affected by, each other.

Electromagnetic Interference (EMI): Any unwanted electrical signal that is radiated or conducted into or out of the electrical equipment, which may disrupt the normal operation of the equipment. EMI can be continuous or intermittent.

Electrostatic Discharge (ESD): ESD can result in damage through excessive voltage spikes. We can offer assistance on whether our products can meet specific ESD test requirements.

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

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.

Elliptical Function Filter (Cauer Transfer Function): Yields the sharpest possible amplitude response for a given number of circuit elements. These filters have a Chebyshev response in both the passband and the stopband but a poorer phase response and transient response than any of the other filter functions.

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

Envelope Delay (Time Delay): The propogation time delay undergone by the envelope of an amplitude modulated signal as it passes through a filter. Envelop delay is proportional to the slope of the curve of phase shift as a function of frequency.


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.

Feed-through: A feed-through is a termianl 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 of pressure, that has terminations on each side.

Filter: A selective network comprise of capacitors, inductors and/or resistors which passes a specific band of frequencies and attenuates the out-of-band frequencies.

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

Fourier Analysis: The process of analyzing a complex wave by separating it into a plurality of component waves, each of hte particular frequency, amplitude and phase displacement.

Frequency: Is a signal of alternating current (AC) that swings from a high peek to a negative point. Each swing from crest to trough of the wave is called a cycle. Frequency is the number of cycles per second that is measured in Hz (Hertz), where 1 Hz = 1 CPS (Cycles per second.

Frequency Range: The range of frequencies in which a component will function properly to its specifications.


Gain: The ratio of power output to the power input of the amplified in dB.

Gigahertz (GHz): The frequency measurement that equals a billion cycles per second. For example: 7 GHz = 7 billion cycles per second.

Gaussian Filter: A filter network designed to pass a step function with zero overshoot and minimum rise time. This is similar to a Bessel Filter.

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

Group Delay: This is the time delay within the passband of a filter and is hte derivative of the phase response with respect to frequency, in radians. Typically the group delay deviation is specified as a peak-to-peak maximum allowable in the passband.

Group Delay Deviation: The deviation is delay between two points within the passband. Increased delay deviation produces modulated signal distortion.


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

Henry: The standard unit for electrical inductance.

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 int he 19th century.

Highpass Filter: A filter that passes high frequencies and attenuates low frequencies.

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


Impedance (as it applies to filters): A measurement of resistance calibrated in “Ohms” which varies with frequency.

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.

Insertion Loss (as it applies to filters): The additional loss between the source and the load caused by the insertion of the filter compared to its absence. It is equal to the sum of the dissipation loss and the reflection (return) loss. This loss is usually expressed in dB. Insertion Loss is determined by:

      • Electrical configuration
      • Source/load impedances
      • The load current (which can cause ferrite saturation)
      • Ceramic dielectric materials. The capacitance change will be affected by applied voltage, temperature and the age of the part
      • Earthing impedance
      • Shielding integrity

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

Insulation: 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.

Insulators: Materials with very high resistance, insulators includes glass, plastic, rubber, etc.

Interference Suppression: Filters suppress electromagnetic interference in two basic ways. The capacitive elements shunt the interference to ground and the inductive elements raise the impedance of the line, making the shunt capacitors even more effective.


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.

Ku Band: Frequencies between 12 and 18 GHz as specified by IEEE Standard 521-1984.


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

Linear Phase Response: A filter that exhibits a constant change in degrees per unit of frequency. The resultant plot of phase versus frequency is a straight line.

Loaded Q (Working Q): A term that defines the percentage of the -3dB bandwidth of a Bandpass Filter.
Q = (F0(Hz)/-3dB Bandwidth(Hz)

Lowpass Filter: A filter that passes low frequencies and attenuates high frequencies, sometimes referred to as an anti-aliasing filter.


Megahertz (MHz): Frequency measurement that equals a million cycles per second. For example, 3 MHz = 3 million cycles per second.

Microwave: A wavelength on the electromagnetic spectrum lying between the infrared and the radio frequency range. Microwaves extend from 1 GHz to 300 GHz.

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

Microstripline: 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.

Microwave: 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 n many applications, including communications.

Minimum Pass Band Attenuation (Amin): Defines the minimum signal attenuation within the stop band.

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.

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

Multiplexer: A device allowing one or more low-speed analog or digital input signals to be selected, combined and transmitted at a higher speed on a signal shared medium or within a signal shared medium devie.


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: Random electrical signals, generated by circuit components or by environmental disturbances.

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

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

Notch Filter: A notch filter passes all frequencies above and below a specific band of frequencies. The frequencies in this band are stopped from passing. This filter is essentially the opposite of a Band Pass Filter.


Order (M): The steepness of the filter.

Overshoot: The amount expressed in percent, by which a signal exceeds its stead state output on its initial rise.


Passband: The frequency range in which a filter is intended to pass signals.

Passband Intermodulation (PIM): Is the interference of a signal. PIM is a nonlinear response that occurs when two or more signals are present in a passive device such as a cable, connector, or coupler. PIM is typically cause by dissimilar metals or dirty/loose interconnects.

Passband Ripple: In a bandpass filter this refers to the wave-like variation in attenuation in the passband of the filter due to load mismatch (VSWR). Classic transfer functions such as Butterworth, Gaussian and Bessel have no ripple while Chevyshev and Elliptical are characterized by equal ripple in the passband.

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

PCB Connector: A connector mounted on printed circuit boards (PCB).

Phase: 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 Shift: The change in time experienced by voltage or current after passing through a circuit or cable. Phase shift is a delay in time that is commonly expressed in degrees or picoseconds when it relates to connectors or cable assemblies.

Power (Average): The average power rating limits high-frequency operation, while the peak power rating usually specified the low frequency.

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

Power Handling: This is hte RF input power beyond which the performance of the filters may degrade or fail, expressed in watts (W). It is typically specified as a continuous wave (CW) value, as an average value that is usually 10 times its CW rating, or both.

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: Moving or transmitting energy along a path.

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

PFTE (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.

Pulse: A rapid change in signal level over a relatively short period of time.


Quality Factor (Q): The Q or figure merit of a filter is a measure of the sharpness of response or its frequency selectivity. Please see “Loaded Q”.


Radiated Interference: Interference transmitted in free air.
Protection is provided by shielding, but if filters are not used to protect against conducted emissions, the unfiltered lines can act as aerials radiating interference outside the shielded cage.

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.

Reflection: 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.

Reflow Soldering: A process that wets the leads and pads with solder by screen printing and then heating to cause the solder to melt.

Rejection: The level, expressed in decibels, at which a filter will attenuate a signal outside its passband. It is specified either at a single frequency or frequencies or a range of frequencies. A filter’s rejection is often also referred to as its attenuation.

Relative Attenuation: Attenuation measured with the point of minimum attenuation in the filter as the zero dB reference point.

Response: The term used to describe how a filter reacts to input signals. It is defined as the ratio of the input signal compared to the output signal (for amplitude response and phase response).

Return Loss (RL): 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 Relflection 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 Leak: The amount of signal frequency which radiates (leaks) from the RF Connector or cable.

Ripple: The wavelike variations in the amplitude response of a filter. Chebyshev & Elliptical Function filters have characteristics such as the differences in peaks and valleys of the amplitude response in the passband are always the same. Butterworth, Bessel & Gaussian Filters do not have ripple. Ripple is usually measured in dB.

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


S Band: S Band is the band of frequency between 2 – 4 GHz; IEEE Standard 521-1984.

Shape Factor: The ratio of Attenuation Bandwidth to 3 dB. Bandwidth for a bandpass filter, 3 dB Bandwidth to Attenuation Bandwidth for a bandstop filter, Attenuation Frequency to Fco for a lowpass filter and Fco to Attenuation Frequency for highpass filter.

Shape Factor (Bandwidth Ratio): In a filter, the ratio comparing hte high-attenuation level bandwidth with the low attenuation level bandwidth, or the ratio of the -3dB bandwidth to the stopband bandwidth.
Bandpass & Notch: S = Attenuation Bandwidth / 3dB Bandwidth
Lowpass & Highpass: S = Attenuation Frequency / 3dB Cut-Off

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

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.

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.

Solder Contact: A contact terminal that accepts a wire for soldering ends by using a cup, hollow cylinder, eyelet or hook.

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.

Soldering: 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.

Step Function: A signal characterized by instantaneous changes between amplitude levels. The term usually refers to a rectangular front wave-form used for making tests for transient responses.

Stopband: That part of the frequency spectrum that is subjected to a specified amount of attenuation by a filter.

Stopband Frequency (FS): The frequency at which the minimum attenuation in the stopband is reached.

Stopband Rejection: The ratio of the unwanted frequency components at the input of the filter to those after it. It is a key filter performance specification because it equates to its rejection capability. Values can range form 20 to 100 dB.

Stripline: 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.

Surface Mount Device (SMD): Abbreviated as SMD, it is an active or passive device designed to be soldered to the surface of a printed circuit board.

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

Susceptibility: The extent to which a piece of equipment is vulnerable to interference emitted from another piece of equipment.


Tcebycheff Filter: See Chebyshev Filter

Temperature: Refers to the minimum and maximum temperatures that a given component can operate at while still meeting the specifications unless otherwise noted.

Termination (Load): Are used at the end of a transmission line and are designed to absorb RF power with very little reflection, effectively terminating the line.

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.

Thermal Shock: A drastic change in temperature causing non-uniform expansion or contractor within a material or a combination of materials that can cause internal parts to separate for each other.

Time Delay: The slope of the phase versus the frequency curve. In a loose sense, this is the time it takes a designated point in a wave to pass through a filter. It is also called envelope 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.

Torque: Recommended mating torque for industry standard connectors: SMT = 7 to 10 in-lbs; Type-N = 12 to 15 in-lbs; TNC = 12 to 15 in-lbs; 7/16 DIN = 220 to 300 in-lbs.

Total Harmonic Distrotion (THD): The measurement of the harmonic distortion present. It is defined as the ratio of hte sum of the powers of all harmonic components to the power of the fundamental frequency. It is used to characterize the linearity of audio systems and the power quality of electric power systems.

Transition Band: The range of frequencies that bound a passband/stopband interface.

Transformer: 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.

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

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


UHF(Ultra High Frequency): Contains the range of 300 to 3000 MHz.


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: An 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.

VHF (Very High Frequency): A frequency band between 30 – 300 MHz.

Voltage Standing Wave Ratio (VSWR): VSWR is the efficiency measurement of how radio frequency is transmitted from a power source through a transmission line, into a termination (or load).


W Band: A frequency band between 75 – 110 GHz. IEEE Standard 521-1984.

Waveguide: 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.

Wavelength: 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.

Working Voltage: Continuous operating voltage.
This can potentially be across the entire operating temperature range.


X Band: A frequency band between 8 – 12 GHz. IEEE Standard 521-1984.