High-Transparency and High-Efficiency Miniaturized Wideband Antenna Using Optimized Wired Metal Mesh for IoT Applications

This paper presents a miniaturized, wideband, and optically transparent antenna with high efficiency, designed using the optimized wired metal mesh (WMM) for Internet of Things (IoT) applications. The performance of transparent antennas based on conductive oxides (TCOs) or metal meshes (MMs) is fundamentally determined by the optical transparency (OT) and sheet resistance (SR) of the material. Although OT and SR can be tuned using various fabrication techniques, conventional SR values provided by existing studies do not accurately represent the loss behavior at GHz frequencies. In this paper, an effective SR material model for the WMM is developed with consideration of high-frequency losses and applied in electromagnetic (EM) simulations. Using this model, the proposed antenna is systematically designed to achieve an impedance bandwidth of 66.3% and peak total efficiency of 92.4% over 2.61-5.2 GHz, in a compact 55×40 mm2 form. In addition to intrinsic antenna performance, practical robustness is evaluated under bending deformation, temperature variation, and indoor propagation environments. In the indoor scenarios having multipath effects, Error vector magnitude measurements at 3.5 GHz and 5.15 GHz demonstrated its suitability for IoT communication environments.