This letter proposes a compact microstrip-to-waveguide transition probe with an integrated DC-bias channel for diode-based doublers, in which the E-fields polarity of the TE₁₀ mode can be manipulated via the monopole branch orientation. Accordingly, a compact 170-GHz Schottky diode frequency-doubling cell is demonstrated, with the output E-field direction tunable to 0° and 180°. Furthermore, a power-combined doubler is realized using controlled E-fields from two doubler cells for in-phase power combining. The single doubler, with two diodes on a 50- μ m-thick substrate, achieves 42.9% peak efficiency and 103-mW output power at 163 GHz. The combined configuration offers ~14% 3-dB bandwidth, delivering 181-mW output power and 36.9% conversion efficiency at 167 GHz with 490-mW input. Comparative tests validate the superior performance of this novel-combining structure.

https://ieeexplore.ieee.org/document/11435498 DOI: 10.1109/LMWT.2026.3672363