Modeling time reversal focusing amplitudes in a reverberation chamber using a modal summation approach

Abstract

Time reversal (TR) is a signal processing technique often used to generate focusing at selected positions within reverberant environments. This study looks at the effect of the location of the focusing, with respect to the room wall boundaries, on the amplitude of the focusing and the uniformity of this amplitude at various room locations. A numerical model based on the summation of room modes was created to simulated the TR process in a large reverberation chamber. This model returned results that showed the peak amplitude of the focusing is quite uniform, and that there is also a notable increase in amplitude for each additional surface that is adjacent to the modeled focal location. With spatial uniformity of focusing within the room and uniform increases when the focusing is near adjacent walls. An experiment was conducted that verified the numerical findings, resulting in the confirmation of both the uniformity and uniform increases as the focusing position is moved near an adjacent wall.