Abstract: A compact rectangular waveguide H-plane T junction over the Ka-band is realized in this paper. By loading capactive flute on the wide side and inductive stage on the narrow side of the T junction, the tunability of the equivalent parameters for the H-plane T junction discontinuity is achieved, and good input impedance matching is obtained throughout the Ka band. The capacitive flute and inductive stage are easily processed with high error tolerance. For demonstration, the RWG H-plane T junction operating at Ka band is designed, fabricated, and measured. The measured return loss is greater than 20 dB from 25 GHz to 40 GHz. The measured insertion loss is less than 3.22 dB, which corresponds to a power-combining efficiency of 95.0%. The measured results are in good agreement with the simulated ones. The proposed power divider has a high power capacity for the waveguide-based structure, which could be used in high power-combining system.