Branch line coupler with cross coupling

A new type of branch line coupler is proposed with increased design freedom and adjustable harmonidspurious response. The proposed coupler has additional cross coupling branches to the conventional hybrid branch coupler. It can be designed in many different ways to achieve the prescribed coupling level, which greatly increases the design flexibility. Also, the different design options show distinct frequency characteristics, which can he used to control the harmonic or the spurious response of the coupler.