Ridge Gap Waveguide Fed Slot Array Antenna with Low Sidelobe Level

A low sidelobe slot array antenna based on ridge gap waveguide (RGW) is presented in this paper. Fed by two-layer RGW structure centrally, the slot array features symmetric field distribution. Offsetting the slots can fine tune the amplitude to obtain a quasi-Taylor distribution, thus resulting in a low sidelobe level. To verify the design idea, an 8-element slot array antenna was designed and simulated. Its simulated impedance bandwidth is found to be 8.9%, with a sidelobe level lower than -20 dB from 76 to 81 GHz.