A compact rectangular waveguide (RWG) H-plane T junction (HT) over the WR28 is realized in this paper. Capacitive flute and inductive stage are adopted to settle the discontinuities of the T junction, by which, the operating bandwidth is expanded to the whole WR-28 band. The capacitive flute and inductive stage are easy 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 24 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.