A compressed-length 90°-bend offset broadside-end-coupled bandpass filter

A 21-22 GHz compressed-length offset broadside-end-coupled three-resonator bandpass filter is presented. The filter length, defined as the distance between the two interface planes governing the input and output ports, is reduced by approximately two-thirds for this filter as compared to the conventional colinear realization. The measured response shows less than 1.5-dB insertion loss and greater than 10 dB return loss in the passband. The noncolinear and offset broadside-end-coupled arrangement of such a filter makes it flexible for interface with the other microwave circuits in a communication system or subsystem design.