Substrate-Integrated Waveguide Ku-Band Cavity-Backed 2 $,\times,$ 2 Microstrip Patch Array Antenna

A Ku-band cavity-backed microstrip patch 2 x 2 antenna array has been implemented using the substrate-integrated waveguide (SIW) technology-a low-cost multilayer printed circuit board (PCB) process. Cavities are emulated using vias, and the patches are fed using microstrip lines that are centrally fed by a shielded coaxial probe feed line. Simple design guidelines for the cavity, patch, and substrate selection are presented. The array was fabricated, and its measured results agreed very well with theoretical predictions and indicated a relatively high efficiency and wide bandwidth of greater than 70% and 9%, respectively.