Compact Wideband Low-Profile Single- and Dual-Polarized Dielectric Resonator Antennas Using Dielectric and Air Vias
Hauke Ingolf Kremer, Kwok Wa Leung, Mike W. K. Lee
Abstract
A low-profile DRA employing dielectric and air vias is investigated. The structure is realized utilizing PCB technology only. The dielectric vias are formed by filling up cylindrical holes with barium strontium titanate (BST) nanoparticles with a dielectric constant of 20 and a loss tangent of 0.023. Using this technique, the antenna can be made compact, without the need for using external, high dielectric-constant materials that are unavailable for standard PCB manufacturing. By skillfully arranging air vias inside the DRA, the resonant frequencies of different modes can be controlled, and a wide impedance bandwidth with stable radiation performance can be achieved. The whole antenna structure can be manufactured using standard PCB materials and manufacturing technologies. Our prototype achieves a wide measured impedance bandwidth of 47.5% and a maximum measured gain of 6.84 dBi. Furthermore, a small antenna footprint of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.616\times 0.616\,\,\lambda _{0}^{2}$ </tex-math></inline-formula> with a low profile of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.095~\lambda _{0}$ </tex-math></inline-formula> is achieved, where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the wavelength in the air at the center frequency. A dual-polarized antenna is investigated using this design technique. It achieves an overlapping bandwidth of 34.88% of its two ports with isolation of higher than 25.76 dB and stable radiation performance across the passband.