Phase Inverters Based on Substrate Integrated Waveguide

Phase inverters (PI) suit a wide range of applications for microwave systems. There are lots of reports about PIs based on microstrip or coplanar waveguide, some of which obtain simple configurations and wide bandwidths. However, there are few reports about PI based on substrate integrated waveguide (SIW). Inspired by a microstrip PI constituted by an interdigital slot and metallic vias, a new SIW PI is proposed for the first time. Furthermore, a phase shifter is inserted to the SIW PI in order to compensate the signal delay. Both prototype and compensation-type PIs represent good transmission performance with return loss better than 10 dB in 8.3-13 GHz. The bandwidth of the prototype can reach 47.6% with phase deviation less than 10° compared with 38-mm transmission line, which shows more excellent performance.