Tunable triple-band millimeter-wave absorbing metasurface based on nematic liquid crystal

Qiang Wang,Wei Xiang Jiang,Yuan Ke Liu,Tie Jun Cui,Gui Chen Wang

doi:10.1063/5.0075606

Qiang Wang, Wei Xiang Jiang + Show 3 more

Open Access

https://doi.org/10.1063/5.0075606

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Abstract

We propose and design a tunable triple-band millimeter-wave absorbing metasurface based on nematic liquid crystal (NLC). Numerical results based on both effective circuit model and full-wave simulations verify the triple-band absorption property. All triple absorption peaks can be shifted by changing the bias voltage applied to the nematic liquid crystal. We fabricate and measure a triple-band absorbing metasurface sample, which covers 100 × 100 mm2 and is composed of 20 × 20 unit cells. In experiments, when no bias voltage is applied to the NLC layer, the resonant frequencies of the absorbing metasurface are 25.4, 28.7, and 32.8 GHz, respectively. When a 5-V bias voltage is applied, all the absorbing peaks redshift, and a frequency tunability range of 9.5%, 9.1%, and 8.58% is observed in three resonant frequencies, respectively. The experimental results are in good agreement with the numerical simulations. The proposed tunable absorbing metasurface provides a way forward for the realization of tunable millimeter-wave metasurface devices that can be applied in multi-band detection and imaging.

Highlights

Limited by processing and parasitic effects, it is hard to extend the tunable devices with common semiconductor components adopted in the microwave band to a higher frequency band
There are some advantages of nematic liquid crystal (NLC)-based active metasurface devices:23,24 First, using NLCs can reduce the scale of the biasing network for the active metasurface devices
NLCs hold a relatively large tuning range of relative permittivity with varying bias voltage, which is beneficial in more advanced wave manipulations

Summary

Introduction

Limited by processing and parasitic effects, it is hard to extend the tunable devices with common semiconductor components adopted in the microwave band to a higher frequency band. We propose and design a tunable NLC-based absorbing metasurface that works in the mmW frequency band. Based on the tunability of NLC materials, the absorbing metasurface can be adjusted by the bias voltage.

Results

Conclusion