Array antenna for body-worn automotive harmonic radar tag

A W-band four-by-four microstrip patch array antenna for body-worn automotive harmonic radar tag is presented in this paper. The antenna is fabricated on 100 mum thick liquid crystal polymer flex foil, using commercially available printed circuit board manufacturing processes. Port impedance and radiation patterns of the antenna are studied numerically and experimentally. The measured results are in good agreements with the numerical simulations. Experimental results indicate that a 2.5 GHz impedance bandwidth (S₁₁=-10 dB) and a 16.4 dBi maximum antenna gain are achieved, at a center frequency around 80 GHz. Experiments with various types of dry and wet textiles are performed in order to study the effect of integration in clothes.