Improving directional radiation quality based on a gradient amplitude acoustic leaky wave antenna

Abstract

In this work, we show how to modify radiation amplitude with a leaky wave antenna to improve the quality of sound radiation. The designed gradient amplitude leaky wave antenna consists of a straight pipe with periodically loaded membranes, open channels and Helmholtz resonators. An equivalent acoustic composite right/left-hand transmission line that considers the effects of viscous-thermal and viscous-elastic losses is utilized to steer the radiation angle continually from backward to forward as a function of the incident frequency. The numerical results show that by appropriately selecting the structural parameters of the channel and Helmholtz resonator cavity, the quality of the directional radiation is improved based on the gradient distribution of the radiation amplitude and the near unitary phase. Compared with traditional antennas, the proposed gradient amplitude antenna incorporates a frequency scanning capability with gradient amplitude, which improves the directivity quality of the acoustic waves among the operated frequency band, and provides a new design method for acoustic leaky wave antennas.New J. Phys. 21 (2019) 103023 J Lan et al

Confined acoustic line modes within a glide-symmetric waveguide

“…Acoustic metasurfaces as a branch of the wider acoustic metamaterial area have received increasing interest for beam-steering 1 – 4 , tailored absorption 5 – 8 , active systems 9 , 10 and acoustic antennas 11 – 13 . Typically these metasurfaces are structured planar geometries that manipulate acoustic waves through the collective interaction of resonators, membranes, space coiling elements etc.…”