Novel structure and design of enhanced-bandwidth hybrid quadrature patch coupler

摘要

A novel structure and design optimization procedure of an enhanced-bandwidth hybrid quadrature patch coupler is proposed. Improved performance of the circuit has been obtained by parameterizing the coupler sections using splines, which introduces additional degrees of freedom. Due to computational complexity of the parameter adjustment problem, a sequential design procedure is applied. In each iteration, a selected number of spline control points is used and their radial coordinates are optimized. The design found this way is then used as a starting point for the next iteration with an increased number of spline control points. The final design parameterized by 20 control points exhibits over 50% bandwidth at the operational frequency of 10 GHz, and acceptable footprint of 13.8 mm x 15.7 mm.