A vertical W-band surface-micromachined Yagi-Uda antenna

A vertical W-band surface-micromachined Yagi-Uda monopole array is proposed and implemented for the first time. The monopoles stand on a high-k soda-lime glass substrate and are fed by a coplanar waveguide. The geometry functions as a vertically placed Yagi-Uda antenna due to the image theory. The performance of the vertical Yagi-Uda is to be superior to conventional W-band printed antennas due to minimum substrate wave effects. A successful implementation of the vertical Yagi-Uda structure is demonstrated using high-aspect-ratio surface micromachining fabrication technologies. The test results of a 5 element structure demonstrate a 10-dB-impedance-bandwidth of 12% at 100 GHz. A directivity of 8.2 dBi is projected for this prototype.