Design of High-Scanning-Rate and Full-Space-Scanning Leaky Wave Antenna Utilizing the Manipulation of Slow Wave Dispersion Curve

Abstract

In this communication, a leaky wave antenna (LWA) based on the manipulation of slow wave dispersion curves, possessing high-scanning-rate and full-space-scanning capacities, is studied. The novelty of this design is presenting a universal technique from the point of the electric current path to control the cut-off frequency and slope of dispersive curve of slow wave units independently without extra loading slow wave layer, and applying it in odd-mode unit, thus realizing the full space scanning and high scanning rate. The odd-mode slow wave unit composed of two “half-cross-shaped” units, creates longitudinal current distribution and omnidirectional radiation components, enabling full space scanning possible. The cut-off frequency and slope of odd-mode unit is independently controlled by manipulating the longest electric current path length and electric field strength between the spacing. In this LWA, by unifying the cut-off frequency and changing the slope of dispersion curve, the spacing length modulation is introduced herein instead of classical groove depth modulation, which fully utilizes unit slow wave property while realizing radiation, thus achieving high scanning rate. The open stopband (OSB) is suppressed by asymmetrically loading a pair of the open-ended stubs at the outer side of periodic radiation structure along the transmission direction. A prototype of LWA is fabricated and measured demonstrating a continuous scanning from -90° to 90° in a frequency band of 11.7 to 13.6 GHz.