COPLANAR WAVE-GUIDE WITH TOP AND BOTTOM SHIELDS IN-PLACE OF AIR-BRIDGES

A convenient technique for the elimination of the coupled slot-line mo de in coplanar waveguide (CPW) nonsymmetric circuits is proposed. This technique simply uses top and/or bottom ground plane shields and avoi ds the more costly air-bridges. These shields are easy to fabricate, h owever, mag slightly affect the propagation of the CPW mode in the for m of power leakage into the parallel plate TEM mode. This effect can b e avoided by restricting operation to lower frequencies. Numerical com parisons between the effect of the shields and the air-bridges on a CP W filter are presented.