Design of Si-based micromachined slot antenna

A trenched silicon-based slot antenna over BCB membrane is investigated. Firstly, a cavity backed slot antenna on a high resistivity silicon (HRS) substrate is designed to achieve wideband performance and high radiation efficiency. The obtained bandwidth is 23% at 25.5 GHz with radiation efficiency of 99%. Then, a trench under both the CPW feed line and the antenna slots is used to replace the cavity. A parametric study is performed to examine the effect of the trench width on both the characteristic impedance of the CPW feed line and the slot antenna performance. In addition, the effect of silicon resistivity on the antenna performance is studied. The final design is based on a 20 /spl mu/m BCB technology over a silicon substrate with resistivity ranging from 11 to 15 /spl Omega/cm. The obtained bandwidth is 37% at 27 GHz with radiation efficiency of 72%. The total used die area is 1 cm/sup 2/.