A novel compact-size Ka-band branch-line coupler

In this study, a novel ka-band compact-size branch-line coupler was reported and fabricated by WIN Semiconductors 0.15 m pseudomorphic high electron-mobility transistor (PHEMT) Process. The design equations was provided and occupied less 45% of the circuit area compared to the conventional design at 30 GHz. The proposed method does not need any lumped elements, via-hole grounding, and bonds wire, which leads to a simple design and fabrication process and low cost.