Slotted substrate integrated waveguide phase shifter

The slotted substrate integrated waveguide (SSIW) phase shifter with periodic loading varactors is presented. With appropriate numbers of varactors placed on the SIW's surface, the phase of two-port device could be varied with the varactors' capacitance, which is inversely proportional to the bias voltage. To prove it, a phase shifter installed seventeen varactors has been designed. There are good agreements between simulated results and experimental ones. In the frequency bandwidth of 2.5 to 3.45 GHz (about 31.9% relative bandwidth), the return loss and inserted loss are mostly better than 10 dB and 5 dB, respectively. At the center frequency of 3GHz, the maximum phase range of 80° is obtained.