Initial Structure Solution for Nonparametric Modeling of Waveguide Devices Based on Time Reversal Technique

The core of modeling microwave devices is to find a better initial structure for it, while nonparametric modeling provides greater design freedom; for this reason, this paper presents a method for finding a physical guidance-based initial structure for non-parametric modeling in microwave waveguide devices. This method involves obtaining the equivalent source inside the waveguide device through a single time reversal (TR) operation. It is avoided that starting from a random or unguided initial structure may hinder the iterative convergence. Furthermore, the internal structure of the waveguide device is obtained through equivalent sources. This article uses TR operation to design two internal structures for a 90° bent waveguide and a bent waveguide power divider operating at 3 GHz, each with a size of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1\lambda\times 1\lambda$</tex>. This initial structure has excellent electromagnetic properties.