A novel wideband microwave gain equalizer using SIR branch lines

A novel wideband microwave gain equalizer based on ceramic substrate is proposed in this paper with microstrip stepped impedance resonators (SIR). SIR lines are introduced to replace UIR lines used in the gain equalizer to increase the bandwidth and input/output return loss. To demonstrate its performance, a modified Microwave gain equalizer with SIR lines has been fabricated and measured. Results show that the measured input/output return loss, minimum insertion loss and equalization are better than 16.5, 2.8, and 10.5 dB, respectively, across a 104% bandwidth from 6 to 19 GHz.