Polarization modulation by tunable electromagnetic metamaterial reflector/absorber

TL;DR

This paper introduces a tunable metamaterial reflector/absorber that electrically controls the polarization state of electromagnetic waves, enabling continuous adjustment of polarization angle and type at microwave frequencies.

Contribution

A novel polarization modulation scheme using a tunable metamaterial with diode-coupled resonant units, allowing independent control of orthogonal polarizations.

Findings

Electromagnetic reflections can be tuned independently for orthogonal polarizations.

The device achieves continuous polarization angle tuning from 0° to 90° at resonance.

Experimental verification confirms effective polarization control at microwave frequencies.

Abstract

We propose a polarization modulation scheme of electromagnetic (EM) waves through reflection of a tunable metamaterial reflector/absorber. By constructing the metamaterial with resonant unit cells coupled by diodes, we demonstrate that the EM reflections for orthogonal polarized incident waves can be tuned independently by adjusting the bias voltages on the corresponding diodes. Owing to this feature, the reflected EM waves can be electrically controlled to a linear polarization with continuously tunable azimuth angle from 0o to 90o at the resonant frequency, or an elliptical polarization with tunable azimuth angle of the major axis when off the resonant frequency. The proposed property has been verified through both numerical simulations and experimental measurements at microwave band, which enables us to electrically modulate the polarization state of EM waves flexibly.