Coplanar-Waveguide Directional Couplers

Design information for coplanar-waveguide directional couplers has been calculated using quasi-static zeroth-order approximations. Experimental results on a 10-dB directional coupler designed from these calculations have shown reasonably good agreement with predictions. The smaller difference in even- and odd-mode velocity in a coplanar-waveguide directional coupler leads to better directivity and better performance than a microstrip directional coupler.