A Wideband Symmetrical Crossover Model With Analytic Analysis and Its Millimeter-Wave Application

A wideband symmetrical crossover model is proposed in this article. The analytic expressions between the
$S$
-parameters and the structure parameters are built through even-odd method. One optimization method is presented to achieve a 44% of bandwidth at sub 6 GHz with the consideration of the physical structure constrain. With the analytic expressions, this model provides a concise and effective method to design crossovers from sub-6 GHz to millimeter-waveband. By utilizing the proposed model and optimization approach, a substrate integrated gap waveguide (SIGW)-based crossover at 30 GHz is designed and verified to provides 20% of the optimized bandwidth, which could be a good candidate component for the 5G Millimeter-wave beamforming network applications.