A Compact Wideband Phase Shifter Using Slotted Substrate Integrated Waveguide

Abstract

A compact phase shifter using substrate integrated waveguide (SIW) with two slots is proposed in this letter. The wideband phase shift is mainly caused by the opposite phase shift slopes produced by the slots and the microstrip delay lines over a wide frequency range. Furthermore, the wide phase shift range (−90° to 90°) can be achieved and be with the same reference line. Compared with the state of the arts, the proposed one gives consideration of the wide bandwidth, wide phase shift range, simple and compact size, and easy-to-make structure, while the SIW counterparts just consider part of the above features. Five prototypes covering the frequency of 26 GHz are designed with the operating bandwidth for 90° ± 5° (−45° ± 2.5°, 45° ± 2.5°, and 90° ± 5°) phase shifter of 26.6% (29.2%, 35.8%, and 39.3%) and the size of <inline-formula> <tex-math notation= LaTeX >$2.29\\lambda _{g}^{2}$ </tex-math></inline-formula> (<inline-formula> <tex-math notation= LaTeX >$2.42\\lambda _{g}^{2}$ </tex-math></inline-formula>, <inline-formula> <tex-math notation= LaTeX >$2.71\\lambda _{g}^{2}$ </tex-math></inline-formula>, and <inline-formula> <tex-math notation= LaTeX >$2.86\\lambda _{g}^{2}$ </tex-math></inline-formula>; <inline-formula> <tex-math notation= LaTeX >$\\lambda _{g}$ </tex-math></inline-formula> is the guided wavelength at the center frequency <inline-formula> <tex-math notation= LaTeX >$f_{0}$ </tex-math></inline-formula>).