Design of a Matching Attenuator for 220GHz Folded-waveguide Traveling-wave Tube

摘要

A matching concentrated attenuator in wedge shape with sever for 220GHz folded-waveguide (FWG) traveling-wave tube (TWT) is designed. From the perspective of dielectric loss, the S11 parameter and S21 parameter of the attenuator are both below -20dB when the permittivity of loss material is set in a range of 6.7 to 7.9 and the loss tangent is in a range of 0.19 to 0.35 at 220GHz. Then the attenuator structure is determined to be an external one with sever. Finally, the S11 parameter of the whole circuit is below -12dB and the reflection power from the circuit input port is far less than input power, which prove the efficiency of the designed attenuator.