A Sidelobe Level Reduction Method for mm-Wave SIW Slot Array Antenna by Only Placing Adjacent Slots on Opposite/Same Side

A novel method to reduce the sidelobe level (SLL) of the substrate integrated waveguide (SIW) slot array antenna by only placing adjacent slots on opposite/same side is presented in this paper. For a SIW slot array, 0°/180° radiation phase can be easily achieved by placing adjacent slots on the opposite/same sides. This feature is applied to reduce the SLL of the SIW slot array easily and effectively. Here, the SLL of a conventional 16×16 SIW slot array antenna is reduced from -13.5 dB to -19.66 dB by simply switching the adjacent slots on the same/opposite side. Simulation results show a good impedance matching from 91.98 GHz to 95.48 GHz and a maximum gain of 26 dBi.