Analysis of time reversal cavity characteristics based on multipath channel model

Abstract

The electromagnetic wave time reversal technology using time reversal cavity (TRC) has potential applications in many areas, such as pulse compression, power synthesis, perturbation detection, beamforming, etc. Microwave chaotic cavity with multi-path transmission characteristics is usually used in TRC. Based on diffraction theory, it can prove that this kind of cavity has spatiotemporal focusing characteristics and can be used for compressing pulses, but it cannot be used to analyze the reversal performance of the cavity. In order to obtain a suitable analysis method and guide the design of TRC, in this work, the scattering, diffusion and attenuation characteristics of electromagnetic wave propagation are analyzed and a multipath channel model of TRC is built by the channel theory. Moreover, the crosstalk characteristics between paths are studied, and the generation mechanism of time sidelobe, time sidelobe shift and interference are also investigated. In addition, under the assumption of random plane wave, the distribution characteristics of spatial focal spot are analyzed, which is consistent with the diffraction theory. Moreover, the actual focal spot size is not only limited by the diffraction limit, but also related to the initial focal spot size. The theoretical analysis results are basically consistent with the experimental and numerical simulation results.