An Isolated Out-of-Phase 3-dB Power Divider via Waveguide-to-Microstrip Transition

In this letter, we present a 3-dB power divider with isolated port. The input port is a rectangular waveguide and two output ports are microstrip lines. The measured results of the power divider show above 12-dB minimum isolation over 13-16 GHz, with an input return loss of better than 15 dB. The return loss of the output ports is better than 10 dB, with an insertion loss of lower than 0.35 dB. A maximum amplitude imbalance of about 0.15 dB is observed within 13-16 GHz, with a phase imbalance of better than 2.5 degrees. The proposed power divider in this letter is compact and good integration with the monolithic microwave integrated circuit (MMIC) devices.