A reflective mm-wave photonic limiter

TL;DR

This paper introduces a reflective mm-wave photonic limiter using a multilayer VO2 structure that switches from transparent to reflective at high power levels, protecting sensitive receivers from damage.

Contribution

It demonstrates a novel, power-controlled, reflective mm-wave limiter based on VO2's phase transition, combining experimental and numerical analysis.

Findings

The limiter effectively reflects high-power signals without damage.

It maintains a nearly constant output above the threshold.

The device operates based on a thermally induced phase change in VO2.

Abstract

Millimeter wave (mm-wave) communications and radar receivers capable of processing small signals must be protected from high-power signals, which can damage sensitive receiver components. Many of these systems arguably can be protected by using photonic limiting techniques, in addition to electronic limiting circuits in receiver front-ends. Here we demonstrate, experimentally and numerically, a free-space, reflective mm-wave limiter based on a multilayer structure involving a nanolayer of vanadium dioxide (VO2), experiencing a thermal insulator-to-metal transition. The multilayer acts as a variable reflector, controlled by the input power. At low input power levels, VO2 remains dielectric, and the multilayer exhibits resonant transmittance. When the input power exceeds a threshold level, the emerging metallic phase renders the multilayer highly reflective while dissipating a small portion of the input power without damage to the limiter. In the case of a Gaussian beam, the limiter has a nearly constant output above the limiting threshold input.