W-band ridge gap waveguide slot array antenna with low sidelobe and high-gain characteristics

In this letter, a W-band slot array antenna based on ridge gap waveguide (RGW) with low sidelobe and high-gain characteristics has been proposed. It adopts a series and parallel hybrid feeding network to realize low sidelobe levels in E- and H-plane, respectively. The tunable pins and large power ratio dividers are introduced in the distribution network, which improves the phase consistency and brings flexibility to amplitude-tapering. The proposed antenna overcomes the shortcomings of grating lobes caused by quasi-Taylor distribution of conventional slot array with backed cavities. The prototype of a 16 x 18 slot array is fabricated and measured. The measured impedance bandwidth is from 81.2 to 86 GHz, and the peak gain is higher than 29.4 dBi with the sidelobe levels (SLLs) of -19.7 dB and -30 dB on E- and H-plane, respectively.