Wiener-Hopf Solution of a Backscattering Protected Waveguide: A Tribute to Professor Zich

This work is dedicated to Rodolfo Zich, a distinguished authority on the Wiener-Hopf technique and a prominent figure in our community, recently passed away. After a thought in memory of Prof Zich, we address the wave propagation phenomena in a parallel plate waveguide with Parity Time-Reversal Duality (PTD) symmetry, and its exact solution using a Wiener-Hopf formulation. The inherent symmetry of these waveguides provides protection against backscattering. Through the combination of the Wiener-Hopf method with a regularization technique, we arrive at closed-form relations that aptly describe the modes within these waveguides.