A 94-GHz aperture-coupled micromachined microstrip antenna

This paper presents an aperture-coupled micromachined microstrip antenna op erating at 94 GHz. The design consists of two stacked silicon substrates: 1 ) the top substrate, which carries the microstrip antenna, is micromachined to improve the radiation performance of the antenna and 2) the bottom subs trate, which carries the microstrip feed line and the coupling slot. The me asured return loss is -18 dB at 94 GHz for a 10-dB bandwidth of 10%, A maxi mum efficiency of 58 +/- 5% has been measured and the radiation patterns sh ow a measured front-to-back ratio of -10 dB at 94 GHz. The measured mutual coupling is below -20 dB in both E- and H-plane directions due to the integ ration of small 50-mu m silicon beams between the antennas, The micromachin ed microstrip antenna is an efficient solution to the vertical integration of antenna arrays at millimeter-wave frequencies.