A Wideband Six-Port Receiver With 40% Effective Bandwidth Using an Optimized 3dB Branch Line Hybrid Coupler

This paper presents a new design of a wideband six-port network for the six-port receiver system. Considering, input matching, isolation, amplitude, and phase imbalances, it shows an effective bandwidth of more than 40%. The wideband operation is achieved using a new two-section branch-line hybrid coupler with excellent phase response. The design concept is validated by implementing a six-port network in a microstrip line technology, which covers the whole X-band. Measurement results show that the phase imbalance is within +/- 7.5 degree, an amplitude imbalance of +/- 1.5 dB and with reasonably good isolation and input matching over the whole band.