Leaky-Mode Generation by Means of All-Metal Corrugated Slotted Parallel-Plate Waveguides

Periodic leaky-wave antennas can be realized with planar low-profile structures supporting the generation of highly directional beams with frequency scanning from backward to forward directions. We propose a method to generate leaky modes with continuous scanning with an all-metal periodic 2-D (i.e., invariant along a direction normal to the propagation) waveguide. Periodic corrugations are introduced to support a slow wave, which is transformed with periodic slots etched on the top plate into a fast radiating waves. Suitable choices of the corrugation and the slot periods lead to a single fast backward-forward spatial harmonic being responsible for well-defined and directional radiation. This new method is demonstrated here proposing an original unit cell, properly optimized to suppress the open stop band. The analysis and the design is accomplished with a rigorous in house periodic method-of-moment code, allowing for the computation of complex modes in open 2-D waveguides. The leaky-wave antenna is studied and validated by means of full-wave simulations in Ka band. The structure features continuous beam scanning with broadside radiation at 29.7 GHz with beam scanning, realized gain, and efficiency comparable to different antenna technologies having thickness ten times larger.