A Novel 180$^{\circ}$ Hybrid Using Broadside-Coupled Asymmetric Coplanar Striplines

In this paper, a new way to realize a 180deg hybrid is presented. This technique utilizes a broadside-coupled asymmetric coplanar-stripline section to meet the tight coupling requirement that usually arises from the traditional reduced-size hybrid-ring configuration. In addition, this coplanar technique facilitates the implementation of a hybrid ring in a cascadable format. While providing a simple design procedure for the device, analytical details are also discussed. An experimental prototype, operating at 2.4 GHz, has been fabricated using conventional printed circuit board technology. Measured performances show good agreement with analytical and full-wave simulations, showing promising potential for a variety of applications such as balanced mixers, power amplifiers, and antenna feed networks.