Open Collections

Abstract

Most multi-mode microwave cavity filters exhibit insertion-loss characteristics which deviate widely from the theoretical responses on the low frequency side of the passband. This paper describes an X-band three-mode filter which inherently overcomes the primary cause of the response discrepancy. The design includes a method of identification of the field configurations within the cavity and a method of relating the coupling produced between two degenerate modes of resonance by a probe to the relative frequency shift caused by the probe. A simple method of measuring insertion loss is shown, and both theoretical and measured insertion loss characteristics are recorded for three bandwidths, 7.4 mc/s, 10.0 mc/s, and 13.6 mc/s, all of which show no extreme discrepancy between the theoretical and measured responses.