A Three-Fed Microstrip Antenna for Wideband Circular Polarization

Author

Lin, Chen ; Zhang, Fu-Shun ; Jiao, Yong-Chang ; Zhang, Fan ; Xue, Xin

Author_Institution

Nat. Lab. of Antennas & Microwave Technol., Xidian Univ., Xi´´an, China

Volume

9

fYear

2010

fDate

7/2/1905 12:00:00 AM

Firstpage

359

Lastpage

362

Abstract

New design of a circular microstrip antenna with three feeds for wideband circular polarization is presented. Detailed theoretical analysis proves that a circular microstrip antenna, which is excited by three central symmetrical feeds with equal amplitudes and relative 120?? phase shifts, can obtain good circular polarization characteristic. A broadband 120?? phase shifter is developed using the metamaterial transmission line (MM TL). It consists of a Wilkinson power divider and three phase-adjusting TLs, namely a MM TL and two microstrips. The antenna is composed of two circular patches. The primary radiating patch under the parasitic patch is excited by three feeds. The proposed antenna can provide an impedance bandwidth of 54.75% and a 3-dB axial ratio bandwidth of 47.88%. The 3-dB gain bandwidth is as large as 40%, with the peak gain 8.8 dBic. In addition, the measured and simulated symmetrical radiation patterns are in good agreement.

Keywords

antenna feeds; broadband antennas; metamaterials; microstrip antennas; polarisation; power dividers; transmission lines; Wilkinson power divider; central symmetrical feeds; circular patches; metamaterial transmission line; three-fed microstrip antenna; wideband circular polarization; Circularly polarized (CP) antenna; symmetrical radiation pattern; three feeds; wideband;

fLanguage

English

Journal_Title

Antennas and Wireless Propagation Letters, IEEE

Publisher

ieee

ISSN

1536-1225

Type

jour

DOI

10.1109/LAWP.2010.2048296

Filename

5447697