Folded C-Type SIW Slot Array Antenna with Sidelobe Suppression for mm-wave Application

In this article, a millimeter wave (mm-wave) multibeam array antenna based on folded C-type substrate integrated waveguide (FCSIW) is proposed, which can suppress the sidelobe level of the E-plane and H-plane radiation patterns. By adjusting the size of the slot element, the excitation amplitude of the slot element can be regulated. So that the excitation amplitude of the slot element presents the Chebyshev distribution, and the sidelobe level with −25 dB of the H-plane radiation pattern can be achieved. In addition, the $4 \times 8$ butler matrix (BM) based on FCSIW is used to excite the $8\times 4$ slot array antenna, which can make the excitation amplitude of the slot array antenna present an approximate Chebyshev distribution along the E-plane, and the sidelobe level with −17dB of the E-plane radiation pattern can be obtained. Finally, the mm-wave multibeam array antenna with sidelobe suppression is designed, which can be used as one of the candidates for 5G mm-wave communication in the future.