Design of Wideband Omnidirectional Two-Layer Transparent Hemispherical Dielectric Resonator Antenna

This communication investigates the wideband omnidirectional two-layer hemispherical dielectric resonator antenna (DRA), excited in its omnidirectional TM101 mode by an axial probe. For the first time, design formulas of the omnidirectional two-layer hemispherical DRA are found by using the covariance matrix adaptation evolutionary strategy (CMA-ES). The formulas are used to design a two-layer transparent hemispherical DRA which simultaneously serves as the covering of a light source. Acrylic and glass are used for the inner and outer transparent layers, respectively. ANSYS HFSS was used to simulate the DRA, and the simulation agrees reasonably well with our measurement. It was found that the transparent two-layer DRA has a measured impedance bandwidth of 31.9%, which is over two times wider than that of the single-layer TM101-mode glass DRA.