A new W-band coplanar waveguide test fixture

A coplanar waveguide (CPW) test fixture suitable for transistor measurements in the 75-110 GHz band is presented. The test fixture provides good RF characteristics and can be integrated monolithically with a GaAs device. The fixture uses finline tapers for the transition from waveguide the CPW, and air bridges to tie the opposing ground planes to the same potential. A simple computer model has been developed to aid in the design of the waveguide-to-CPW transitions. A prototype fabricated on low-dielectric-constant substrate has 4-dB loss from 85-95 GHz.<
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