Novel Substrate-Integrated Waveguide Phase Shifter and its Application to Six-Port Junction

A complementary split-ring resonator (CSRR)-loaded substrate-integrated waveguide (SIW) phase shifter and its application to a six-port junction is presented and demonstrated in this article. Different from the prior evanescent-mode analysis, this article concentrates on the TE10-mode analysis of CSRR-loaded SIW, and a slow-wave effect is observed. The CSRR offers a simple resolution to a slow-wave structure in SIW and can be verified by the CSRR equivalent-circuit model theory. Hence, an equal-length wideband 90° phase shifter (35%) can be realized by a proper design of the fast-slow-wave hybrid transmission line (TL). The phase velocity decrease caused by the slow-wave effect contributes to the length reduction of the phase shifter as well and makes it more compact. Furthermore, the widespread application of CSRR also helps generalize the slow-wave effect, and a more compact phase- shifter-based half-mode substrate-integrated waveguide (HMSIW) is obtained. To experimentally validate this concept, a dual-layer six-port- junction-based HMSIW is designed, simulated, and fabricated. The application of the slow-wave TL in a six-port design helps in the bandwidth enhancement and size reduction of the component, which makes it more applicable to demanding systems with complex requirements such as detecting and transceiver systems. The measured results are in accordance with the simulated data.