A Compact Broadband Phase Shifter Based on HMSIW Evanescent Mode

A compact broadband phase shifter based on the half-mode substrate-integrated waveguide (HMSIW) is proposed in this letter. By etching interdigital capacitor or adding blind holes and patches into the HMSIW, the width of the HMSIW can be reduced. Moreover, based on the complementary phase responses of series capacitance and shunt capacitance loading on the HMSIW, a broadband phase shifter is designed with a small phase deviation. To validate the proposed design approach, two phase shift channels and the reference channel are fabricated and measured. Phase shifts of 86° ± 2.5° (and 43.5° ± 2.5°) with fractional bandwidths of 53.3% (and 35.7%) covering central frequencies of 7.5 GHz (and 8.4 GHz) are achieved. The insertion losses of the three channels are 0.76-1.32, 0.40-0.63, and 0.87-1.40 dB, respectively. Besides, the area of each branch is only 0.343λ
_g
²
; λ
_g
is the guided wavelength at the center frequency in the dielectric.