PLANAR MILLIMETER-WAVE ANTENNAS USING SINX-MEMBRANES ON GAAS

Planar aperture coupled microstrip antennas for 77 GHz are demonstrate d for the first time. As far as possible standard GaAs monolithic micr owave/millimeter-wave integrated circuit (MMIC) technology is used to realize the antennas. The antenna patches are suspended on a thin diel ectric SIN, membrane on GaAs substrate. Therefore a novel plasma-enhan ced chemical vapor deposition (PECVD) process step for the fabrication of the membranes is developed and described. The single antenna patch es are coupled to a microstrip line through an aperture in the ground metallization. The method of moments in spectral domain is applied to design the patches, The feed network of a 3 x 1 antenna array for homo geneous excitation is simulated and optimized with a microwave design system (RIDS). From reflection measurements the operation frequency of this triple patch antenna is determined to be 77.6 GHz. The farfield antenna characteristics are measured in an anechoic chamber, showing g ood agreement between simulated and measured results and a co- to cros s-polarization isolation better than 30 dB.