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Main Authors: Smith, David R., Sazegar, Mohsen, Yoo, Insang
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2406.06102
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author Smith, David R.
Sazegar, Mohsen
Yoo, Insang
author_facet Smith, David R.
Sazegar, Mohsen
Yoo, Insang
contents A common variant of a metasurface antenna consists of an array of metamaterial elements coupled to a waveguide feed. The guided wave excites the metamaterial elements, coupling energy from the waveguide mode to radiation. Under appropriate conditions, each sub-wavelength metamaterial element can be modeled as a polarizable dipole, with the polarizability determined by an extraction procedure from the computed or measured waveguide scattering parameters. Here we establish the equivalence of this polarizability description of a metamaterial element with an equivalent circuit model, providing an additional tool for metasurface design that offers significant insight and a path towards efficiently modeling very large apertures. With this equivalence established, more complicated external circuits that include lumped elements and devices such as diodes and transistors can be integrated into the metamaterial element, which can then be transformed into an equivalent polarizability for modeling in the coupled dipole framework. We derive appropriate circuit models for several basic metamaterial elements, which provide direct relationships between the equivalent circuit parameters of an element and its effective polarizability. These expressions are confirmed using scattering parameters for several example structures obtained via full-wave simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2406_06102
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Equivalence of Polarizability and Circuit Models for Waveguide-Fed Metamaterial Elements
Smith, David R.
Sazegar, Mohsen
Yoo, Insang
Applied Physics
A common variant of a metasurface antenna consists of an array of metamaterial elements coupled to a waveguide feed. The guided wave excites the metamaterial elements, coupling energy from the waveguide mode to radiation. Under appropriate conditions, each sub-wavelength metamaterial element can be modeled as a polarizable dipole, with the polarizability determined by an extraction procedure from the computed or measured waveguide scattering parameters. Here we establish the equivalence of this polarizability description of a metamaterial element with an equivalent circuit model, providing an additional tool for metasurface design that offers significant insight and a path towards efficiently modeling very large apertures. With this equivalence established, more complicated external circuits that include lumped elements and devices such as diodes and transistors can be integrated into the metamaterial element, which can then be transformed into an equivalent polarizability for modeling in the coupled dipole framework. We derive appropriate circuit models for several basic metamaterial elements, which provide direct relationships between the equivalent circuit parameters of an element and its effective polarizability. These expressions are confirmed using scattering parameters for several example structures obtained via full-wave simulations.
title Equivalence of Polarizability and Circuit Models for Waveguide-Fed Metamaterial Elements
topic Applied Physics
url https://arxiv.org/abs/2406.06102