160 GHz silicon micromachined folded slot antenna array

This paper describes the design, electromagnetic (EM) modeling and experimental results obtained for a 160 GHz double folded slot antenna array processed through silicon micromachining. Initial simulations showed reflection losses (RL) of -17 dB at 160 GHz and a fractional bandwidth of ~18.7% (with RL<;-10dB between 148.65 GHz and 178.59 GHz). The simulated directivity was larger than 4 dBi in the working frequency band and ~6.8 dBi at 160 GHz. The structure was processed through deep reactive ion etching (DRIE), and resulted in a thinner substrate than designed. The experimental results for this thinner substrate of about 140 μm showed a ultra wideband behavior, with measured RL<;-10dB for almost the whole 140-210 GHz band and -17 dB at 160 GHz. The free space transmission parameter was measured and the results were compared with the simulated directivity showing a frequency shift of the curve, but otherwise a very good agreement in the trend of the two curves.