Broadband Phase Shifters using RC-Allpass-Networks and Active Balun Circuits

Synthesis procedures for symmetrically and unsymmetrically loaded RC-allpass bridge circuits are presented. Phase shifters with 900 ± 200 from 1 MHz to 4 GHz are obtained by switching between two RC-allpass networks of second order and a section of line in one of the RC-allpasses. With active balun circuits the overall transmission loss is close to 0 dB.