Automated Attenuation Test in Multimodal Waveguides by Resonance Return-Loss or Insertion-Loss Measurements

Two methods for testing short lengths of multimodal circular waveguides, working in the TE₀₁ mode accompanied by many spurious modes are described. One method is based on the measurement of the return loss of a resonant one-port cavity; the second one measures the insertion loss of a cavity coupled to the rectangular main waveguide. Automatic data selection and manipulation are emphasized.