Waveguide Attenuator
Understanding Waveguide Attenuators
Waveguide attenuators are essential for power level control, receiver protection, and measurement system calibration in waveguide-based systems.
Waveguide Attenuator Types
- Fixed (vane): Resistive card fixed in the waveguide. Specific attenuation value (3, 6, 10, 20 dB).
- Variable (rotary vane): Attenuation follows cos^2 law based on vane rotation angle. Most accurate type. 0-60 dB range.
- Continuously variable (flap): Resistive card moved in/out of waveguide. 0-20 dB range.
- Precision step: Calibrated step attenuator for precise level setting.
Frequently Asked Questions
What is a waveguide attenuator?
A waveguide attenuator absorbs controlled amounts of power using resistive vanes or cards inside the waveguide. Fixed (specific value), variable (adjustable), or precision (calibrated). Higher power handling and better match than coaxial.
What is a rotary vane attenuator?
A rotary vane attenuator uses three resistive vanes where the center vane rotates. Attenuation = -40*log(cos(theta)) dB. Extremely accurate and repeatable. The gold standard for attenuation measurement up to 60 dB.
How much power can waveguide attenuators handle?
Fixed vane: 10-100 W average depending on vane material and cooling. Water-cooled versions: 1 kW+. Rotary vane: 1-10 W (low attenuation), limited by heating at high attenuation settings.