A 210–225-GHz Wilkinson Power Divider/Combiner Based on Rectangular Waveguide for Traveling-Wave-Tube Applications

This article presents a waveguide Wilkinson power divider with high-power capacity for G-band (210–225 GHz) traveling-wave-tube (TWT) power combining. To begin with, a topology that integrates a lossy ceramic-loaded waveguide, a stepped twist section, a Y-junction, and short-circuit matching stubs is proposed and analyzed theoretically. The even odd mode model indicates that ceramic-loaded waveguides exhibit matched losses under odd-mode excitation while maintaining transparency under even-mode excitation, and the twist section provides the required 90° polarization rotation in less than$\lambda $g/2. Then, full-wave simulations show return loss >19 dB and isolation >13 dB over 211–217 GHz, peaking at 29.4 dB at 211 GHz. With 200 W injected into each isolated port, the peak electric field everywhere remains well below breakdown, confirming high-power capacity. Parameter sweeps are performed on the length and width of the matching stub loaded on the terminal to ensure the tolerance characteristics of the device. At the same time, it was confirmed that the isolation only decreased by about 1 dB when the device accommodated a 0.2-mm CNC filet. Finally, a G-band vector network analyzer was used to measure the oxygen-free copper prototype manufactured by high-precision CNC milling. The measurement results are in good agreement with the simulation performance, verifying the feasibility of using it for power synthesis between terahertz (THz) TWTs.