Differential SIW slot antenna array with intrinsic common‐mode rejection

Abstract

In this study, the differential substrate integrated waveguide (SIW) slot antenna array is proposed with intrinsic common-mode (CM) rejection. Through field analysis, it is found that the SIW is a natural differential transmission line which can only transmit differential signal due to the characteristics of hybrid electromagnetic boundary perfect electrical conductor and perfect magnetic conductor. Hence, it can also be seen as a natural balun with intrinsic CM suppression. Thus, a compact 1 × 4 differential SIW slot antenna array with high CM rejection can be designed using the differential microstrip transition structure which has little conversion between differential-mode (DM) and CM. For the design of differential SIW passive device, the DM equivalent half circuit is a single-ended SIW device with height halved. Further, the 4 × 4 differential SIW antenna array with high CM rejection can be designed with a T-shaped differential SIW four-way power divider. The 1 × 4 and 4 × 4 differential SIW antenna arrays are fabricated and good agreements between the simulated and measured results demonstrate the validity of proposed configurations.