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  Variable Attenuators

The variable attenuator is used to adjust power, reduce reflection interaction, and provide isolation for certain components where needed. These attenuators contain a section of waveguide with a narrow slot milled in the broad wall. Through this slot, a thin metalized mylar vane is introduced into the waveguide by a precision micrometer. The driver mechanism is arranged to provide 0-30 dB of attenuation over .300 inch travel on the micrometer dial. Featuring no backlash, these units will produce accurate and reproducible settings.

CMI Offers these parts made from coin silver waveguide as a custom product. Send email to for quote.

This product is now available with a metric micrometer drive assembly.

Ordering Example: VA28S is a Variable Attenuator in WR28 with Square Flanges.

Ordering Information
To order please send email to Sales and indicate the part #s and quantities desired.
 Catalog #  Waveguide Size  Flange
 VA42R  WR42  Square - 0.875
 VA34R  WR34  Square - 0.875
 VA28R  WR28  Square - 0.750
 VA22R  WR22  Round - 1.125
 VA19R  WR19  Round - 1.125
 VA15R  WR15  Round - 0.750
 VA12R  WR12  Round - 0.750
 VA10R  WR10  Round - 0.750
 VA8R  WR8  Round - 0.750
 VA6R  WR6  Round - 0.750
 VA5R  WR5  Round - 0.750
 VA4R  WR4  Round - 0.750
 VA3R  WR3  Round - 0.750
 VA2.2R  WR2.2  Round - 0.750