Numerical characterisation of multi-layered CPW directional couplers

This paper presents a numerical characterisation of two 3 dB multi-layered CPW directional couplers, which were fabricated at King's College London. The quasi-TEM models of the couplers are studied with the help of a 2-dimensional finite element program. The characteristic impedances for both couplers obtained are in a good agreement with the values measured in the experiment.