Non-Uniform Polylines Enabled Slow-Wave Half-Mode Substrate Integrated Waveguide for Flexible Phase Shifting Application

The recently emerging beyond fifth-generation (B5G) and sixth-generation (6G) mobile communications demand flexible phase shift controlling ability to enable its multi-channel multi-functional transmit/receive systems. In this work, slow-wave half-mode substrate integrated waveguide (SW-HMSIW) patterned with non-uniform polylines of various lengths for flexible phase shifting application is presented. By periodically patterning polylines into the conventional HMSIW, product of the equivalent permittivity and permeability of this composite medium can be enhanced effectively, thus to influence the phase constant of the transmissible waves in it, and the slow-wave effect and associated size reduction will be achieved. Hence, by varying lengths and widths of segments of the polylines differently, the equivalent permittivity and permeability of the SW-HMSIW can be changed, and consequently its phase constant will be differently as well, namely phase shift function is realized. To demonstrate this idea, a size-miniaturized broadband SW-HMSIW phase shifter is implemented. Measured results agree with the simulation well, which indicates its suitability for phase controlling applications in future communication systems.