A 3-D micromachined W-band cavity-backed patch antenna array with integrated rectacoax transition to waveguide

A 2×2 array of W-band cavity-backed patch antennas with integrated rectacoaxial feed and transition to WR-10 waveguide is presented in this paper. The array and its components are fabricated using a sequential surface micromachining technique. Each antenna has a simulated 4.1% 10-dB return-loss bandwidth about 94.5 GHz, a radiation efficiency of 95%, and a gain of 8.3 dB at broadside with a 76 degree 3-dB beamwidth. The gain of the entire array is 14.3 dB. To facilitate system integration and measurement, an integrated rectacoax-waveguide transition is included, with a simulated insertion loss of −0.1 dB. Measured return-loss shows good correlation to simulation, with a 10-dB return loss bandwidth of 4.6 GHz (4.9%), and a broadside gain of 10 dB at 95.9 GHz is also measured.