A quadrature-hybrid design using a four-port elliptic patch

Available designs of quadrature hybrids have used transmission lines, and recently, circular-disk patches. This paper introduces a four-port quadrature hybrid using a microstrip elliptic patch. It is shown that this configuration has good performance as a quadrature hybrid over a fairly large bandwidth. The performance is improved by the introduction of matching networks. The analysis is carried out using the cavity model Green´s function with appropriate corrections for the fringing fields. A comparison of experimental and theoretical results show good agreement