Affiliations: [a] National Key Laboratory of Antennas and Microwave Technology, Xidian University, Xi'an, Shaanxi, China | [b] School of Physics and Optoelectronic Engineering, Xidian University, Xi'an, Shaanxi, China
Correspondence:
[*]
Corresponding author: Zhi-Ya Zhang, National Key Laboratory of Antennas and Microwave Technology, Xidian University, Xi'an 710071, Shaanxi, China. E-mail:zhiyazhang@163.com
Abstract: A circularly polarized (CP) spiral antenna array for
wideband application is presented, which employs a simple single-arm spiral
antenna (SASA), as the radiating element. By introducing a small round disc
backed near the antenna center and loading a termination resistor, the SASA
achieves a wide impedance bandwidth without a balun circuit and a good axial
ratio (AR) performance, respectively. A total of four array elements are
used in the 2 × 2 configuration to obtain a higher gain. Particularly,
a method of sequentially rotating the elements is used to improve the axial
ratio. The array performs an impedance bandwidth for VSWR ≤ 1.5 of
40% ranging from 1.25 to 1.88 GHz, an excellent AR of better than 0.74
dB, and a gain variation from 11.34 to 14.56 dB within the operating band.
Measured and simulated results presented for the array confirm its wide
impedance, axial ratio, and gain bandwidths. Acceptable agreement between
the simulation and measured results validates the proposed design.
