Abstract: A broad band microwave stripline magic tee designed for a center microwave frequency is disclosed. The magic tee includes a pair of 3db quadrature couplers connected in tandem to one another through a 90.degree. differential phase shift circuit. Each of the 3db quadrature couplers includes a first port, a second port, a third port and a fourth port. The 90.degree. differential phase shift circuit includes first and second conductors therein having apparent electrical lengths that differ from one another by 270.degree. at the microwave center frequency. The second port of the first coupler is serially connected through the first conductor of the phase shift circuit to the first port of the second coupler, and the third port of the first coupler is serially connected through the second conductor of the phase shift circuit to the fourth port of the second coupler.

Abstract: A ground plane element in a channel has a width slightly less than the channel width, thus forming a ridge mode waveguide. Means such as conducting strips are used to suppress the ridge mode. The strips are preferably corrugated for good contact and to firmly secure them. The suppressing means can prevent bypassing a microwave low pass filter.