From vehicles to building windows and computer monitors, the optically transparent antenna could benefit many applications. Pushing the envelope for this technology is a hollow, rectangular glass dielectric resonator antenna (DRA) that also serves as a light cover. The team behind this work includes Kwok W. Leung, Yong M. Pan, Xiao S. Fang, Kwai-Man Luk, and Hau P. Chan from the City University of Hong Kong together with Eng H. Lim from Malaysia’s Universiti Tunku Abdul Rahman.
This DRA, which is centrally fed by a coaxial probe, is excited in its fundamental transverse-magnetic (TM) mode. It thereby generates linearly polarized omnidirectional fields. Four powered light-emitting diodes (LEDs), which serve as the light source, are placed inside the hollow regions of the glass DRA. The team found that the lighting and antenna parts do not interfere with each other.
Both linearly and circularly polarized designs are provided. The glass DRA can generate circularly polarized yields by adding metallic patches onto its side walls with a 3-dB axial ratio bandwidth of ~7%. To attain a completely light-transmissible circularly polarized glass DRA, conducting indium-tin-oxide (ITO) patches are used in place of the metallic patches. See “Dual-Function Radiating Glass for Antennas and Light Covers—Part I: Omnidirectional Glass Dielectric Resonator Antennas,” IEEE Transactions On Antennas And Propagation, Feb. 2013, p. 578.