A Compact Wideband Dual-Polarized Printed Antenna with Coaxial Feeds for TD-SCDMA Application

Yujie Liu,Wei Tang,Yuehe Ge,Guogang Li

doi:10.4236/wet.2015.61001

Abstract

In this article, a low-profile wideband dual-polarized planar printed dipole antenna, fed by coaxial lines, is investigated for the TD-SCDMA operation. The antenna is composed of two printed dipoles, two pairs of feeding coaxial lines and a ground. The single-polarized planar printed rectangular dipole and petal dipole, with the similar configuration, are first studied, exhibiting the potential wideband operation. Two petal dipoles are then cross-arranged to design a dual-polarized planar printed antenna, giving a lower profile and a better bandwidth covering the Chinese TD-SCDMA band (1880-2400 MHz). The dual-polarized antenna is simply excited by two pairs of coaxial feeds. Simulated and measured results show that the antenna achieves a common impedance bandwidth of 42% at both ports, good isolation of more than 25 dB, stable radiation patterns and the gain of about 7 dBi over the operating bandwidth.

Highlights

The population of mobile communication systems is growing continuously
One of reliable antenna elements for base-station antennas is the dipole antenna with a balanced feed
The length of the open copper core, h2, should be about λg/4 in order for the balun to feed the planar dipole antenna

Summary

Introduction

The population of mobile communication systems is growing continuously. The increasing capacity issue is becoming critical because of the expansion of wireless services and the number of mobile subscribers. A planar petal-shape dipole antenna with coaxial feeding mechanism is developed for wideband applications. Two pairs of such planar printed dipole antennas with two DC grounded coaxial feeds and backed by a PEC ground form a wideband dual-polarized antenna element for base station antennas. One of inner copper cores is connected to a 50 Ω SMA connector underneath the ground and a small metallic strip, printed on the top surface of the substrate. The length of the open copper core, h2, should be about λg/4 (λg is the guided-wavelength in coaxial line) in order for the balun to feed the planar dipole antenna.

Petal Dipole with Coaxial Feeder

Dual-Polarized Planar Printed Dipole with Coaxial Feeder

Findings

Conclusion