All-Metal Circular Corrugated Waveguide Leaky-Wave Antenna

This paper presents the analysis and design of an allmetal, elongated corrugated leaky-wave antenna (LWA) designed for omnidirectional conical beam-scanning applications in the Ku/K-band. The antenna is based on a cylindrical corrugated rod, which can be modeled as a solid of revolution derived from a one-dimensional periodic profile. A rigorous modal analysis is performed on the corresponding linearized unit cell of this profile, using an in-house Method-of-Moments (MoM) solver to characterize the complex propagation constant of the supported TM01 leaky mode. The antenna is specifically designed to operate in the backward-wave region (14-19 GHz), a feature that is possible thanks to the periodic nature of the proposed structure. A specialized feeder, incorporating a conical transition and a tapering strategy for the unit cells, is designed to ensure efficient mode excitation and to avoid direct feed radiation in space. Full-wave simulations in CST Microwave Studio validate the design, demonstrating the frequency-scanning capability in the backward quadrant toward the broadside direction (reaching 3.3° at 19 GHz), with peak directivity values ranging between 11.5 and 15.3 dBi. Ongoing work aims to achieve continuous backward-to-forward beam scanning without performance degradation, while effectively suppressing the open stopband. The proposed all-metal architecture represents a robust and versatile solution for terrestrial, space, and aeronautical applications requiring elongated structures. Future investigations will also address deployable implementations.