A Double Tapered Microstrip Leaky Wave Antenna

A double layout of leaky-wave antennas (LWAs) based on tapered design has been proposed and investigated. The single curve tapered Leaky-wave antenna, was designed running a simple procedure which use an FDTD code. A suitable metal walls down the centerline connecting the conductor strip and the ground plane of the LWA, allows to use only half of the structure, the adoption of a simple feeding, and the reduction of sidelobes. The good performance of single tapered microstrip LWA are mainly wider band (33% for VSWR<2), and higher gain (12 dBi) that can be improved using an array with a double LWAs (bandwidth of 39.6% for VSWR<2 and gain of 3.5 dBi). Since the tapering of linear LWA involves the variation of all the emitted rays a closed formula to predict the main beam angle of tapered LWA was obtained. Moreover, as the relative dielectric constant of the substrate approaches 1, the leaky wave antenna bandwidth becomes much wider, improving further its performance.