A waveguide switched-susceptance (diode-patch) phase shifter

A digital p-i-n diode phase shifter that operates in double-ridge waveguide is described. The phase shifter consists of several split conductive patches etched on a dielectric strip which is inserted in the longitudinal direction in the waveguide. The upper and lower half of each split patch are electrically connected by a diode that is switched between forward and reverse bias to shift the phase in the waveguide. A four-patch 22.5 degrees phase shifter and a five-patch 45.0 degrees phase shifter were designed and fabricated using a computer design program. The measured voltage standing-wave ratio and phase shift performance of the phase shifters are shown. Both phase shifters have less than 0.4-dB insertion loss and less than -40-dB interwaveguide coupling.<>