A Novel Cruciform TE$_{10}$/TE$_{20}$ Dual-Mode Power Divider Based on Groove Gap Waveguides

In this article, a class of novel power divider (PD) with TE $_{10}$ /TE $_{20}$ dual-mode operation characteristic is proposed and demonstrated for the first time. The PD is based on low-loss groove gap waveguides with half-height pins and is shaped into a cruciform $E$ -plane coplanar magic-T, which has four coplanar waveguide arms. Unlike all conventional magic-Ts, its $E$ -plane waveguide dominates TE $_{20}$ mode, and $H$ -plane waveguide dominates TE $_{10}$ mode. Herein, compact waveguide transformers, waveguide steps, and cuboid waveguide ridges are employed to achieve broadband impedance matching, efficient mode conversion, and compact dimension. Therefore, the input power can be equally divided whether TE $_{20}$ mode is excited at the difference port or TE $_{10}$ mode is excited at the sum port. Conversely, TE $_{10}$ and TE $_{20}$ modes with equal power can be obtained by exciting TE $_{20}$ mode at any output port. In either case, the free port helps improve the isolation. Moreover, a broadband TE $_{10}$ –TE $_{20}$ mode converter is designed and fabricated to facilitate the measurement. The proposed prototypes are verified in the WR-4 band, and the measured results are excellent and in good agreement with the simulated results within the desired 180–250 GHz.