Analysis of Leaky-Wave Radiation From Corrugated Parallel-Plate Waveguides With Steerable Beams by Rotatable Corrugations

This article presents a modal analysis entailing classical vector potentials and asymptotic corrugations boundary conditions for treating a leaky-wave antenna (LWA) composed of a corrugated parallel-plate waveguide with mutually rotatable grated surfaces and whose upper grille is penetrable to the exterior space. Beam steering at fixed frequencies is achieved by rotating both or either of the base and top gratings, thus finding roles that conventional frequency-steered LWAs are unable to serve. Within millimeter-wave (mm-wave) and THz regimes where components become strongly miniaturized, the advantages of electronic beam-scanning at lower microwave frequencies begin to get offset by the benefits of mechanical steering. Not only does the rotational form of steering enjoy the benefits of simplicity and low cost, it also circumvents the need for complex networks at mm-wave/THz regimes required by electronic-steering that annuls the strengths of LWA in the first place. The rotation in the horizontal plane also offers high weight-handling capability, making it all the more able to manage miniaturized structures at mm-wave/THz regimes. Numerical results computed by the modal approach are validated with those simulated by commercial software. Measurements on a manufactured prototype demonstrate the efficacy of the steerable LWA just as the numerical designs have predicted.