A Wideband High-Gain Electrochromic Antenna With Variable Color and Infrared Emissivity

In this communication, an electrochromic antenna with wideband and high gain is designed, fabricated and measured. Herein, an hydrochloric (HCl)-doped polyaniline (PANI) porous film with excellent infrared (IR) regulation ability is fabricated via in situ electrochemical deposition on an Au substrate, which can realize modulation of emissivity in the range of 0.835–0.455 ( $\Delta \varepsilon = 0.38$ ) and 0.773–0.420 ( $\Delta \varepsilon = 0.353$ ) in the range of 8– $14~\mu \text{m}$ and 2.5– $25~\mu \text{m}$ , respectively. Furthermore, in order to eliminate the high shielding of electromagnetic wave due to Au layers, we have innovatively structured the electrochromic material and treated it as part of the partially reflective surface (PRS). The measured results show that the electrochromic antenna exhibits a good impedance matching over a frequency of 9.35–12 GHz with a peak gain of 15.03 dBi. The 3-dB gain bandwidth can reach 13.9% (from 9.4 to 10.8 GHz). Also, the proposed antenna can change its color between yellow and dark green by electrical control in the digital imaging system and adjust IR radiation in the thermal imaging system. The developed electrochromic antenna may serve as a good candidate for multispectral camouflage or intelligent IR thermal management applications.