MEMBRANE-SUPPORTED COPLANAR WAVE-GUIDES FOR MMIC AND SENSOR APPLICATION

Membrane-supported coplanar waveguides (CPW's) are needed for low-disp ersive and low-loss millimeter-and submillimeter waves as well as for power sensor applications. This letter demonstrates CPW's on polyimid membranes micromachined on gallium arsenide (GaAs) that meet the requi rements of a typical microwave monolithic integrated circuit (MMIC) pr ocess. The influence of the design parameters is simulated by finite d ifference in frequency domain (FDFD), in excellent agreement with the experiment. For a membrane CPW with ground to ground spacing of only 5 0 mu m and characteristic impedance of 115 Omega, relative effective d ielectric constants near 1.02 and attenuation of 0.14 dB/mm at 25 GHz have been achieved.