Tunable Multibeam Periodic Leaky-Wave Antenna Based on Radiation of Multiple Space Harmonics

Abstract

This letter proposes a tunable multi-beam periodic leaky-wave antenna (LWA) based on radiation of multiple space harmonics. The LWA is composed of a microstrip transmission line and a set of stubs. When the main transmission line is loaded with one / two / multiple groups of periodic stubs, one / two / multiple <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$n = - 1$</tex-math></inline-formula> space harmonics that are in the radiation region can be obtained, which are superpositioned to generate one / two / multiple beams. By adjusting the connections between the stubs and the line with switch diodes, the number of beams and the radiation directions can be reconfigured at a fixed frequency. The working mechanism of the tunable multi-beam antenna is investigated. A prototype of tunable dual-beam LWA is fabricated and measured. The measurement results show that two beams can be generated and can be reconfigured independently at a fixed frequency, with maximum gains of 7.93 dBi and 5.48 dBi, respectively.