Ku-band analog phase shifters using individually designed all-pass networks with BST tunable capacitors

This paper describes the design of Ku-band phase shifters based on all-pass filters and BST tunable capacitors. With high tunability capacitors using thin-film BST, each all-pass section can achieve 90 degree or greater phase shift. 360 degree phase shift can be achieved by cascading four sections of the all-pass tunable filters. Especially, these four all-pass sections are designed with two different center frequencies. The center frequency of the phase shifter is 13 GHz. Two of the sections have the center frequency lower than 13 GHz, while the other two are higher than 13 GHz. Numerical and experimental data show that this staggered structure has flatter insertion loss and phase shift compared to previous designs..