Hybrid planar NRD-guide magic-tee junction

A new magic-tee circuit is proposed and developed, which is based on the hybrid integration technology of a planar and nonradiative dielectric (NRD) guide. The magic-tee junction combines an NRD-guide T-junction with a microstrip T-junction. Furthermore, LSM/sub 10/-mode radiators are introduced in the magic-tee circuit to reduce its resonance problem. Measured results show that an isolation of 20 dB can easily be achieved between the sum and difference ports.