RF Definitions: Terminology

Terminology RF (PDF)

Attenuation

The natural reduction in signal power that occurs when a signal travels over a long distance. Attenuation is measured in decibels (dB) as a unit of length.

Corona

The minimum voltage at which the breakdown of air gaps will not occur.

DWV

Dielectric Withstanding Voltage is the minimum voltage level the connector insulating material can withstand before causing a dielectric failure.

Frequency

RF signal is an AC (alternating current) waveform that swings from a high peak or positive point to a low or negative point. Each swing from the positive peak to the negative low of the sine wave is called a cycle. Frequency is the number of cycles per second.

GHz

Frequency measurement that equals a billion cycles per second 1 GHz = 1 billion cycles per second, 6 GHz = 6 billion cycles per second.

Impedance

Resistance measurement calibrated in "Ohms" which varies with frequency. The RF Connector selected must be the same impedance as the system in which it is used. For example, 50-Ohm connectors must be used with 50-Ohm cable while 75-Ohm connectors and 75-Ohm cable must also be used together.

Insertion Loss

The loss of signal power due to the insertion of a connector or another component in the transmission path. Insertion loss is usually measured in decibels as the ratio of the signal power measured before the component insertion point compared to the signal power measured past the insertion point.

MHz

A frequency measurement that equals a million cycles per second. 1 MHz = 1 million cycles per second, 800 MHz = 800 million cycles per second.

Mismatch

The condition where the impedance of a source doesn't match the impedance of the connected component. An example would be using a 50-Ohm connector with 75-Ohm cable would result in an impedance mismatch.

RF

Is the abbreviation for "Radio Frequency."

RF Leakage

The amount of transmitted signal that radiates from the connector.

Semi-Rigid

A cable containing a flexible inner conductor and dielectric but has more rigid outer insulators. Semi Rigid cable assemblies are sometimes called "plumbing" since they often resemble small metal liquid pipes.

SHF

Super High Frequency is the frequency band from 3000 MHz to 30,000 MHz.

Sine Wave

A wave which can be expressed as the sine of a linear function of time and /or space.

Skin Effect

Is the likelihood of an AC signal to travel near the surface of a conductor. Skin effect is a reason many conductors or connector contacts are plated in conductive materials such as gold, versus the expense of using an all gold conductor.

UHF

Ultra High Frequency is the frequency band from 300 to 3000 MHz

VHF

Very High Frequency is the frequency band from 30 to 300 MHz

VSWR

Voltage Standing Wave Ratio is the ratio of transmitted signals versus the reflected signals going through the RF connector. A VSWR of "1:2" means the ratio between the transmitted signal "1" to the unwanted reflected signal "2."