How to select an RF Attenuator
An rf attenuator is an electronic device that reduces the amplitude or power of a high frequency signal with minimal distortion. Attenuators are used for a number of applications, the most common being to reduce the amplitude of an incoming signal, which may be too high to process.
The key specifications to look for in an rf and microwave attenuator are:
Type’s of rf attenuators:
· Fixed Attenuators: These attenuators have a fixed attenuation value for a set frequency range.
· Variable Attenuators: Variable attenuators, like the name suggests are attenuators whose attenuation can be changed by varying the voltage or current to the device. These are used in application where it is required to continuously vary the signal level.
· Step Attenuators: These are attenuators whose attenuation can be modified in fixed steps. These have many applications especially in test labs where different attenuation levels are required for testing different circuits.
· Programmable Attenuators: These attenuators are programmed to provide a certain level of attenuation.
Frequency (MHz): This is the frequency range over which the attenuator can operate with while providing a constant level of attenuation with minimal reflections.
Attenuation (dB): This is the ratio of the output and input power levels.
Power (W): The level of power that an attenuator can handle is the amount of power the device can dissipate while maintaining the signal integrity i.e the Attenuation level with minimal reflections.
Impedance (Ohms): The impedance of an attenuator must match the circuit/system it is connected to; this will minimize any reflection within the circuit/system. Usually the impedance is 50 Ohms or 75 Ohms.
Package Type: RF Attenuators are available in various package types depending on the application – Connectorized attenuators are the most common and are available with various connector options – SMA, N Type, BNC etc., surface mount attenuators are used in circuits and Bench top attenuators are used in labs for test and measurement.
Other Parameters: There are a number of other parameters that are used to search for attenuators - Voltage, Bits, Directionality etc.