Fixed attenuator

A device used to reduce power levels of a signal by a fixed amount with little or no reflections. The output signal is attenuated relative to the input signal while the input and output impedance is maintained close to 50Ω (or 75Ω) over the specified bandwidth. Hence, this device is often used to improve interstage matching in a circuit.

Flatness

The total variation in attenuation over the specified frequency range. Flatness generally becomes worse at higher frequencies where attenuation starts to increase with increasing frequency.

VSWR

Voltage-standing-wave ratio is a measure of the deviation from 50Ω or 75Ω of the input and output impedance. A VSWR of 1.0:1 represents a perfect 50Ω or 75Ω match. A VSWR slightly greater than 1.0:1 represents a slight impedance mismatch, implying a small amount of signal reflection.

Termination

An ideal load of impedance Z0, when connected to the end of a transmission line whose characteristic impedance is also Z0 will absorb all power in the transmission line traveling toward the load.

Maximum RF power

The amount of power that can be applied to an attenuator or load which does not result in excessive heating of the attenuator or load.

Return loss

The minimum return loss the termination exhibits when used for terminating a transmission line it is designed to match. For an attenuator, return loss is measured at one port when the other port is terminated in 50 or 75Ω for which it is designed.

Browse all RF attenuators

Browse all RF terminators