Optically Invisible Artificial Magnetic Conductor Subarrays for Triband Display-Integrated Antennas

This article proposes a novel concept of an optically invisible artificial magnetic conductor subarrays for bandwidth improvement of display-integrated antennas in millimeter-wave spectrums. The proposed subarrays consist of two unit-cell types that are arranged as 4 \times 4 super cells to cover target bands of a slotted dipole antenna with triband resonances. The optical transparency is realized by using thin-metal meshes, and both solid and thin-metal mesh prototypes are fabricated to demonstrate the proposed concept from antenna characteristics standpoints. The mesh prototype exhibits the measured 10-dB matching bandwidth of 25.9% at 28.2 GHz with an average gain of 1.12 dBi, which is similar to 21.1% at 27.5 GHz and 1.25 dBi of the simulated results. These results confirm that the proposed concept is feasible to broaden bandwidths of the triband antenna, while maintaining the optical transparency of 85.1%.