A W-Band High Radiation Efficiency with BCB-Air Cavity-Backed Antenna Based on Through Silicon Ring Trench

The design of a W-band BCB-air cavity-backed antennas is presented in this letter. The three-dimensional (3-D) capacitance model of the cavity-backed structure is analyzed and the design methodology is illustrated in detail. The proposed antenna is fabricated by using our in-house silicon-based MEMS photosensitive composite film fabrication process by combining localized backside etching technology and through silicon ring trench. The measured impedance bandwidth (-10 dB) of the antenna is from 88.9 to 93.7 GHz with a maximum gain 8.2 dBi and 95% radiation efficiency at 91 GHz, higher the gain and radiation efficiency by 2.2 dB and 35%, respectively, as compared with the case without TSRT. The measured results show close agreement with the simulated results. The proposed antenna can be further 3-D heterogeneously integrated with other components because of low interconnection loss to enhance the high-frequency performance for future millimeter wave radar and communication systems.