A high performance surface-micromachined elevated patch antenna

In this paper, an air-filled elevated microstrip antenna resonating at 25 GHz based on surface micromachining technology is fabricated and characterized for the first time. The antenna is air-lifted on high-epsi_r soda-lime glass substrate and demonstrates a 7% 10 dB bandwidth in measurement. A 10.2 dBi directivity and a nearly frequency-independent broadside radiation pattern over a range of 7 GHz around the center frequency are projected in simulation and currently are experimentally investigated. The elevated patch is fed by a vertical epoxy-core metal-coated micromachined probe and supported by several epoxy posts underneath. By the unique feeding technique we have developed in this paper, the dielectric filled between the patch and the ground is air only and the requirement of low-epsi_r substrate for patch antennas and high-epsi_r, substrate for compact feeding network can be satisfied simultaneously. The performance degradation for traditional microstrip antenna directly built on high-epsi_r substrate is alleviated a lot due to the elimination of surface waves in the substrate