Improved design for symmetrical six-port microstrip coupler (based on double-ring-with-star topology)

Other researchers have designed a symmetrical six-port microstrip coupler that yields a bandwidth of 7%. It has been found in this paper that a change of the design topology allows the coupler's bandwidth to be increased. A simple-to use computer model of the double-ring-with-star prototype has also been developed and tests have confirmed that good agreement can be expected between the predicted and measured results.