An Optically Invisible Ionic Liquid Antenna for Millimeter-Waves Vehicular Communications

In this letter, an optically invisible antenna with high gain and wide band is investigated by utilizing transparent ionic liquids for millimeter (mm)-waves vehicular communications. The antenna consists of ionic liquids, acrylic containers, and a transparent conductive film (TCF). The wideband and high-gain operating characteristics are achieved by using the low-loss frequencies-insensitive ionic liquids. Meanwhile, by introducing surface-mounted horn structures and TCF walls, the antenna's radiation gain has been improved. Measured results agree well with the simulated results, demonstrating that the proposed antenna has a frequency range from 12.75 to 18.27 GHz (
S
₁₁
<−10 dB) with a maximum measured gain of 11.5 dBi and high transparency of 83.2%. The proposed transparent ionic liquid antenna could be used as an appropriate candidate for mm-waves Internet of Vehicles.