What is RF Attenuator? 3 Types with Specification of fixed, step & variable attenuators


Usuaully RF Attenuators type including fixed attenuators, step attenuators & variable attenuators. Attenuators are usually passive devices made from simple voltage divider networks. Switching between different resistances forms adjustable stepped attenuators and continuously adjustable ones using potentiometers. For higher frequencies, precisely matched low VSWR resistance networks are used.

Fixed attenuators in circuits are used to lower voltage, dissipate power, and improve impedance matching. In measuring signals, attenuator pads or adapters are used to lower the amplitude of the signal to a known amount to enable measurements or to protect the measuring device from signal levels that might damage it. Attenuators are also used to ‘match’ impedance by lowering apparent SWR.

What is RF Attenuator? 3 Types with Specification of fixed, step & variable attenuators 12

Attenuator Specification

Key specifications for attenuators are:

Attenuation is expressed in decibels of relative power. A 3 dB pad reduces power to one-half, 6 dB to one-fourth, 10 dB to one-tenth, 20 dB to one hundredth, 30 dB to one thousandth and so on. For voltage, you double the DBS so for example 6 dB is half in voltage.

Nominal impedance, for example, 50 ohm
Frequency bandwidth, for example, DC-6 GHz
Power dissipation depends on the mass and surface area of resistance material as well as possible additional cooling fins.
SWR is the standing wave ratio for input and output ports

Attenuators characteristics

Radiofrequency attenuators are typically coaxial in structure with precision connectors as ports and coaxial, microstrip or thin-film internal structure. Above SHF special waveguide structure is required.

  • Accuracy
  • low SWR
  • flat frequency-response and repeatability.

The size and shape of the attenuator depend on its ability to dissipate power. RF attenuators are used as loads for and as known attenuation and protective dissipation of power in measuring RF signals.

Attenuators in Centron RF

About our fixed Attenuators, We have a 2W-500W range of power, N-JK, SMA-JK, BNC-JK, and DIN-J/N-K Type connectors. DC-3GHz/4GHz/6GHz frequencies. We also have step variable attenuators, 2W-10W DC-3GHz 50ohm with N-KK or SMA-KK connectors.