A Wideband Circularly Polarized Pinwheel-Shaped Planar Monopole Antenna for Wireless Applications

Abstract

A wideband circularly polarized pinwheel-shaped planar monopole antenna fed by a wideband feeding network is presented in this paper. The proposed antenna is formed by four wideband planar monopole antenna elements with aquadruple feeding network in order to improve the performance of circular polarization. Additionally, the antenna, which is introduced here, has a high gain in the z axis direction because of its folded antenna structure. The attractive characteristics of the proposed antenna are the wide impedance bandwidth of 87.3 % (1 GHz to 2.55 GHz), the 3 dB axial ratio (AR) bandwidth of 92.3 % (1.05 GHz to 2.85 GHz), and the maximum gain within the 3 dB AR bandwidth is about 8.24 dBic. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Ⅰ. IntroductionWith the rapid progress of wireless technology in recent years, various wireless systems such as GSM, WCDMA/UMTS, Bluetooth, WLANs, and GPS have been highly integrated into mobile devices, and in order to fulfill the RF system requirements using the different frequency band, antenna technology is required to conform to wideband characteristics. Although the planar monopole antenna (PMA) has a simple and compact antenna structure, PMA is a good competitive solution for such a system because of its wide impedance bandwidth [1]. There are several techniques, such as a beveled structure, a shorting strip, a multiple feeding strip, and a loaded plate to increase the impedance bandwidth in the PMA [2]～[4].On the other hand, many modern wireless communication systems, such as radar, navigation, satellite, and mobile applications, use the circular polarized (CP) radiation pattern. The attractive advantages of the CP antenna are as follows. Firstly, since the CP antenna sends and receives in all planes, the CP antenna is strong enough for the reflection and absorption of the radio signal. In the multipath fading channel environment, the CP antenna overcomes the phase problem, which can cause dead-spots, decreased throughput, and reduced overall system performance. Additionally, The CP antenna is more resistant to signal degradation due to inclement weather conditions [5].Conventional CP antenna is achieved by trimming opposite corners of the patch corners [6], inserting the thin slots on patch [7], and using coplanar waveguide [8]. A tilted monopole antenna array [9] with the feeding structure of in-phase signals also generates CP characteristic. However, in these cases, due to the narrow 3 dB axial ratio, it is not possible for practical use. Previous studies have sought to solve this problem [10]～[14]. Stacked configurations with a patch element are employed and the bandwidths are less than 30 %. Broadband single-patch CP microstrip antennas with dual capacitivelycoupled feeds are proposed. They feature the ...

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“…Circularly polarized (CP) antennas have been widely used in wireless communication systems because of their ability to mitigate propagation effects, reduce polarization mismatch, and enlarge system capability [1][2][3][4][5][6][7][8][9][10][11]. The rapid growth of modern wireless systems has also increased the demand for compact antennas with multiband resonance.…”

Compact Circularly Polarized Composite Cavity-Backed Crossed Dipole for GPS Applications

“…In particular, GPS receiver antennas are required to have right-hand circular polarization (RHCP), a wide 3-dB axial ratio beamwidth that faces the sky, and a high front-to-back ratio to avoid interference from the ground. Various types of CP antennas were introduced to operate at GPS bands, including the microstrip antennas [2], [3], near-field resonant parasitic antennas [4], [5], crossed dipole antennas [6], and pinwheel-shaped planar monopole antennas [7]. However, most of these designs essentially focused on the CP generation or 3-dB AR bandwidth enhancement rather than improvement of the 3-dB AR beamwidth.…”