Multi-Octave Metamaterial Reflective Half-Wave Plate for Millimetre and Sub-Millimetre wave Applications

TL;DR

This paper introduces a novel multi-octave reflective half-wave plate for millimeter and sub-millimeter waves, achieving a 150% bandwidth using a unique phase-shift mechanism involving electric and magnetic conductors.

Contribution

It presents a new reflective HWP design based on different phase-shifts from electric and magnetic conductors, enabling broader bandwidths than previous devices.

Findings

Achieved 150% operational bandwidth in experimental tests.

Demonstrated effective polarization modulation across millimeter and sub-millimeter wavelengths.

Introduced a novel phase-shift mechanism for HWPs.

Abstract

The quasi-optical modulation of linear polarization at millimeter and sub-millimeter wavelengths can be achieved by using rotating half wave plates (HWPs) in front of polarization sensitive detectors. Large operational bandwidths are required when the same device is meant to work simultaneously across different frequency bands. Previous realizations of half wave plates, ranging from birefringent multi-plate to mesh-based devices, have achieved bandwidths of the order of 100%. Here we present the design and the experimental characterization of a reflective HWP able to work across bandwidths of the order of 150%. The working principle of the novel device is completely different from any previous realization and it is based on the different phase-shift experienced by two orthogonal polarizations respectively reflecting off an electric conductor and off an artificial magnetic conductor.