Wideband Circularly Polarized Ellipse Antenna Array with Gain Enhancement

Li Wang,Chang-Liang Zhao,Xiao-Wei Shi,Guang Fu,Rui Zhang,Xi Chen

doi:10.1155/2018/3158365

Li Wang, Chang-Liang Zhao + Show 4 more

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https://doi.org/10.1155/2018/3158365

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Abstract

In this paper, a wideband circularly polarized (CP) antenna element and array with gain enhancement are presented. The original antenna element adopts two orthogonal ellipse dipoles with end-loading pillars. In order to achieve a wide impedance bandwidth (IBW), a harpoon-shaped feed patch (HSFP) as electromagnetic coupling-feed is utilized. By introducing a coupled frame and a loop cavity, the gain of the element is crucially improved. Then, four sequentially rotated elements placed in a circular contour act as 2 × 2 array, and a similar loop metal cavity is employed to the array to reach gain enhancement. For the wideband CP performance of the proposed antenna, a wideband phase shifting feed network (WPSFN) is used to construct the antenna. Finally, to verify the feasibility of the proposed antenna, a prototype array is manufactured and measured. Experimental results are found in acceptable agreement with the simulated ones in terms of gain, radiation efficiency, radiation pattern, reflection coefficient, and axial ratio (AR). The result indicates that the proposed antenna has an IBW for reflection coefficient S11 ≤ − 10 dB of 85.7% (0.80–2.00 GHz). Moreover, benefit from the sequentially rotated technique (SRT), the AR at broadside direction keeps blow 3 dB during the overlapped bandwidth of S11≤ − 10 dB, and the ARBW for AR ≤ 1 dB of 74.4% (0.85–1.78 GHz) can be achieved. By employing the loop cavity, the right hand circularly polarization (RHCP) gain is significantly improved, which keeps above 10.00 dBic from 1.05 GHz to 1.85 GHz, and the peak gain reaches to 13.91 dBic.

Highlights

With the rapid development of modern wireless communication system, circularly polarized (CP) antennas with advantages of anti-multi-path, better mobility, less polarization loss, and higher weather penetration have been widely used in various systems, such as compass navigation system (CNSS), global positioning system (GPS), radio frequency identification system, and local area network
A loop cavity is drawn into the antenna element to increase the peak gain to 8.75 dBic significantly
From the analysis of the loop cavity, a same technique is adopted to the array, while the peak gain reaches to 13.91 dBic and the band width of 55.2% (1.05–1.85 GHz) for gain ≥ 10 dBic are obtained

Summary

Introduction

With the rapid development of modern wireless communication system, CP antennas with advantages of anti-multi-path, better mobility, less polarization loss, and higher weather penetration have been widely used in various systems, such as compass navigation system (CNSS), global positioning system (GPS), radio frequency identification system, and local area network. As discussed in [7], by loading a lightning-shaped slot, a dual-broad CP bandwidth of 13.3% and 16.9% was reached All this kind of antenna have several drawbacks, such as bidirectional radiation and deformed radiation pattern. As reported in [8], by employing an artificial magnetic conductor (AMC) with the SPS crossed dipole antennas, a 3 dB ARBW of 29.6% was obtained. It has been demonstrated in [11] that a crossed dipole antenna with parasitic element could achieve a wide 3 dB ARBW of 63.4%. Most of this kind of antennas show broad IBW and ARBW, whereas they suffer

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Conclusion