Focusing Waves at Arbitrary Locations in a Ray-Chaotic Enclosure Using Time-Reversed Synthetic Sonas

TL;DR

This paper introduces a novel wave focusing technique in complex enclosures using time-reversed synthetic sonas, enabling arbitrary target focusing without initial transmitter placement, validated through microwave experiments.

Contribution

The method allows wave focusing at arbitrary locations inside complex enclosures using numerically calculated signals, expanding time reversal applications beyond initial transmitter constraints.

Findings

Effective wave focusing achieved at arbitrary points

Reconstruction quality depends on enclosure loss and port coupling

Metrics predicted by scattering-parameter statistics

Abstract

Time reversal methods are widely used to achieve wave focusing in acoustics and electromagnetics. A typical time reversal experiment requires that a transmitter be initially present at the target focusing point, which limits the application of this technique. In this paper, we propose a method to focus waves at an arbitary location inside a complex enclosure using a numerically calculated wave excitation signal. We use a semi-classical ray algorithm to calculate the signal that would be received at a transceiver port resulting from the injection of a short pulse at the desired target location. The time-reversed version of this signal is then injected into the transceiver port and an approximate reconstruction of the short pulse is created at the target. The quaility of the pulse reconstruction is quantified in three different ways and the values of these metrics are predicted by the statistics of the scattering-parameter $|S_{21}|^2$ between the transceiver and target points in the enclosure. We experimentally demonstrate the method using a flat microwave billiard and quantify the reconstruction quality as a function of enclosure loss, port coupling and other considerations.