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

This letter proposes a tunable multibeam 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 n = -1 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 multibeam antenna is investigated. A prototype of a 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 and 5.48 dBi, respectively.