Zelder, Thomas; Lluch, Elena Vallés; Geck, Bernd; Rolfes, Ilona; Eul, Hermann (Institut für Hochfrequenztechnik und Funksysteme, Leibniz Universität Hannover, Appelstr. 9A, 30167 Hannover, Germany)
In many applications a directional coupler with a high directivity is needed. Therefore, a tunable directional coupler will be presented in this paper. The tunable coupler consists of a conventional directional coupler and a tuning network. By tuning the network, it is possible to increase the directivity of the conventional coupler. The tuning network can either be realized in software or hardware. In this paper the theoretical derivation and an example for a practical realization of the tunable coupler will be presented.