Propagation Characteristics of Mode-Selective Transmission Line

Propagation characteristics of mode-selective transmission line (MSTL) are systematically investigated in this work. Thanks to the frequency-enabled mode selectivity, different mechanisms are used to determine the phase and attenuation characteristics of MSTL over different frequency ranges. With the full-wave simulations, a direct correlation between phase constants of MSTL and related individual modes of interest is conducted, illustrating well-behaved variable phase characteristics of MSTL. For the attenuation characteristics of MSTL, conductor and dielectric losses are separately examined and compared to those of microstrip line and dielectric-filled rectangular waveguide (RWG). These analysis results are verified by the measured results of fabricated prototypes of MSTL, microstrip, and RWG up to 110 GHz.