Compact Ka-Band Magic-T Using Waveguide to Microstrip Dual-Probe Transition

Traditional waveguide Magic-T development typically explores suitable combinations of waveguide E - and H -plane T-junctions, which causes its inevitable bulky volume and limited integratability. Aiming at this difficulty, this letter evolves a novel hybrid Magic-T to provide a substitute option. The proposed configuration uses a universal rectangular waveguide (RW) as a sum port for input, and two microstrip probes are inserted in its E -plane and distributed symmetrically along the E -field-max axis to form the output ports. Then, the difference port connected by two coupling slits is placed on the opposite side of the microstrip probes. Therefore, this structure has a very compact size and the ability to integrate directly with the active chips because it avoids the use of waveguide T-junctions and employs a microstrip outputs setup. A Magic-T prototype has been fabricated and measured, and the results show great performance across the entire 26-40 GHz ( Ka -band), including low loss, high isolation, and good amplitude/phase consistency.