Inverse Design of Perfectly-Matched Metamaterials Via Circuit-Based Surrogate Models and the Adjoint Method

TL;DR

This paper introduces a novel inverse design approach for perfectly-matched metamaterials (PMMs) using circuit-based surrogate models and the adjoint method, enabling broadband, reflectionless devices with complex functionalities.

Contribution

It develops a new inverse design methodology for PMMs combining circuit models and the adjoint method, advancing broadband and reflectionless metamaterial device design.

Findings

Designed a broadband beam-collimator with prescribed amplitude taper.

Created a multi-input multi-output beamformer with zero scan loss.

Demonstrated the effectiveness of inverse design for complex PMM devices.

Abstract

In this work, perfectly-matched metamaterials (PMMs) are described and combined with inverse design to realize broadband devices. PMMs are discretized metamaterials with anisotropic unit cells selected from a constrained design space, referred to as perfectly-matched media. PMMs exhibit the unique property that all their unit cells are impedance-matched to each other as well as to the host medium they are embedded within under all excitations. As a result, PMM devices rely on reflectionless refractive effects to achieve a prescribed function. This property enables true time delay performance and promises broadband capabilities. Two design examples are presented to demonstrate the potential of inverse-designed PMMs: a compact, broadband beam-collimator with a prescribed amplitude taper and a multi-input multi-output beamformer exhibiting zero scan loss.