Theory and experiment of isotropic electromagnetic beam bender made of dielectric materials

TL;DR

This paper presents a new design for an isotropic electromagnetic beam bender using deformation transformation optics, which is easier to fabricate and operates broadband with low loss, validated through experiments.

Contribution

It introduces an isotropic beam bender design based on DTO, simplifying fabrication compared to metamaterial approaches and demonstrating broadband low-loss performance.

Findings

Experimental validation of the isotropic bender for TE waves

The isotropic bender operates with broadband and low loss

Simpler design and fabrication process than metamaterial benders

Abstract

In this paper, we utilize the deformation transformation optics (DTO) method to design electromagnetic beam bender, which can change the direction of electromagnetic wave propagation as desire. According to DTO, the transformed material parameters can be expressed by deformation tensor of the spatial transformation. For a beam bender, since the three principal stretches at each point induced by the spatial transformation are independent to each other, there are many possibilities to simplify the transformed material parameters of the bender by adjusting the stretches independently. With the DTO method, we show that the reported reduced parameters of the bender obtained by equivalent dispersion relation can be derived as a special case. An isotropic bender is also proposed according to this method, and it is fabricated by stacking dielectric materials in layered form. Experiments validate the function of the designed isotropic bender for a TE wave; it is also shown that the isotropic bender has a broadband with low loss, compared with the metamaterial bender. The isotropic bender has much easier design and fabrication procedures than the metamaterial bender.