Ka-Band Filtering Antenna Array Based on Gap Waveguide Technology

In this letter, a filtering antenna array is designed and operates at Ka-band based on the gap waveguide (GWG) technology. The filtering function is achieved by using the GWG filtering feeding network, incorporated with ridge gap waveguide and groove gap waveguide (GGW). The GGW cavity is cascaded vertically to excite the microstrip patches. Finally, 8 × 8 filtering antenna array prototype is fabricated and measured with WR-28 waveguide flange. The filtering antenna array is fed by the WR-28 with a transition from GWG to WR-28 waveguide. Due to low loss characteristic of the GWG filtering feeding network, the measured antenna gain is more than 25 dBi with –25 dB cross polarization. Its working frequency is centered at 35.25 GHz with 4.3% impedance fractional bandwidth. There is a good agreement between measurements and simulations.