Low side-lobe substrate integrated cavity antenna array using unequal microstrip-ridge gap waveguide feeding network at 94 GHz

In this paper, a 4×32 low side-lobe slot antenna array using unequal microstrip-ridge gap waveguide (GWG) feeding network at 94 GHz is presented. The slot antenna array is built by two double-sided printed circuit boards (PCBs). The top one employs SIW-based 2×2 subarrays and the bottom one is a broadband 2×16 way unequal GWG feeding network. Applying Taylor amplitude weighting in the 16 way GWG feeding network, low side-lobe performance is achieved. The unequal T-junction dividers with phase compensation are proposed and designed for various output ratios. Simulated results show that the antenna array achieves 5 GHz bandwidth with a peak gain of 26.3 dBi at 94 GHz. Across the entire band, low side lobe level (SLL) below −20 dB is realized.