A Dual-Polarized Omnidirectional Antenna With Small Plane Size for Indoor Distribution Applications
Jian Zhou, Yan‐Hui Ke, Jian‐Xin Chen
Abstract
A dual-polarized omnidirectional antenna for indoor distribution with small plane size and low deviation from omnidirectionality (DFO) is presented. This antenna consists of a vertical-polarized (VP) element and a horizontal-polarized (HP) element. The VP element consists of two orthogonal pieces and a top-loaded disk, whereas the HP element is composed of two dipoles, a feeding network and a dielectric resonator (DR). The DR is introduced to reduce the plane size of the antenna; meanwhile, low DFO of the HP element can also be obtained. The overall size of the proposed antenna is 0.36 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> × 0.36 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> × 0.26 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> (with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> being the wavelength of the lowest frequency). The measured results show an overlapped bandwidth of 35% (0.71–0.99 GHz) (| <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> | < −10 dB) with DFO less than 1.6 dB for the VP element and 1.85 dB for the HP element. In addition, the cross-polarization levels in azimuth plane are lower than −20 dB for two elements.