# Parallel-Plate Waveguides Formed by Arbitrary Impedance Sheets

## TL;DR

This paper explores the theoretical design of parallel-plate waveguides created by arbitrary impedance metasurfaces, deriving dispersion relations and analyzing guided modes for various configurations.

## Contribution

It introduces a comprehensive theoretical framework for analyzing waveguides formed by arbitrary impedance sheets, including derivations of dispersion relations for different resonant conditions.

## Key findings

- Dispersion relations for waveguides with arbitrary impedance sheets derived.
- Guided modes analyzed for various resonant impedance configurations.
- Predictive models for waveguide behavior based on metasurface parameters.

## Abstract

In this work, we introduce and study parallel-plate-waveguide structures that are formed by two penetrable metasurfaces having arbitrary sheet impedances. We investigate the guided modes which can propagate in such structures and derive the corresponding dispersion relations. Different scenarios including series- and parallel-resonant impedance sheets are considered. The obtained theoretical formulas are applied to predict the dispersion properties for different separations between the two symmetric or asymmetric metasurfaces.