A Highly Isolated Dual-Band Substrate Integrated Waveguide Phase Shifter with Large Phase Tuning Range

This paper presents a novel dual-band substrate integrated waveguide (SIW) reflective-type phase shifter. It employs a dual-mode SIW coupler, which can concurrently couple the TE10 and TE20 modes, forming two passbands. By tuning multiple-resonance loads of the coupler, independently controllable phase shifts with a large tuning range are achieved in both bands. Moreover, by exploiting the orthogonality of TE10 and TE20 modes, the cross-interference between the two passbands can be suppressed to an extremely low level, achieving a much higher isolation level compared to state-of-the-art dual-band phase shifters. A dual-band phase shifter prototype operating at 2.4 GHz and 4.55 GHz is designed. Measured results reveal that it can realize continuous phase shift ranges of 430° and 557° at 2.4 GHz and 4.55 GHz, respectively. The measured maximal cross-interference phase/amplitude errors are 0.37°/0.02 dB and 0.8°/0.1 dB at 2.4 GHz and 4.55 GHz, respectively, validating the effectiveness of the proposed method.