Broadband printed circuit 0 degrees /180 degrees couplers and high power inphase power dividers

A broadbanding procedure that can increase the useful bandwidth of rat-race couplers and Gysel-type power dividers considerably (at least doubled) is described. The resulting circuits have the following advantages: (1) isolation between even and odd mode inputs is excellent and all ports are matched; (2) very flat amplitude characteristics, low phase-deviation from the nominal value, and low loss are obtained; (3) convenient and realizable characteristic impedances of the lines are involved; and (4) the design is based on a clear concept of bandwidth improvement, which can be logically continued. The circuits are easily fabricated, and relative bandwidths in excess of 40% are reached. Applications are seen for high-power combiners, electronic components such as mixers and push-pull amplifiers, and antenna beamforming networks, especially for low-sidelobe antennas. >