First-order model of symmetrical six-port microstrip ring coupler

Abstract

A brief description is given of how the simple eigenmode approach can be utilized to develop a first-order model that yields explicit ready-to-use formulas for predicting the performance characteristics of a symmetrical six-port microstrip ring coupler. Prototype tests conducted over the 2-5 GHz frequency range show the agreement between the predicted and measured values of the coupler's scattering coefficients to be within ±0.05 for magnitude and ±10° for phase.