Affiliations: [a] Science and Technology on Antenna and Microwave Laboratory, Xidian University, Xi'an, Shaanxi, China | [b] School of Physics and Optoelectronic Engineering, Xidian University, Xi'an, Shaanxi, China | [c] Collaborative Innovation Center of Information Sensing and Understanding at Xidian University, Xi'an, Shaanxi, China
Correspondence:
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Corresponding author: Zhi-Ya Zhang, Science and Technology on Antenna and Microwave Laboratory, Xidian University, Xi'an, Shaanxi, China. E-mail:zyzhang@xidian.edu.cn
Abstract: A novel miniature circularly polarized (CP) microstrip
antenna with beamwidth improvement is proposed. The approaches employed in
this design to improve the beamwidth performance are to utilize four
vertical conductive walls around the radiation patch and to locate four
metal isosceles triangle patches at the top of the radiation patch. Four
slots are etched along the diagonals of radiation patch with the ground
plane folded to achieve the miniaturization of the antenna by extending the
current path. In addition, by introducing an electromagnetic coupling feed
and a compact broadband phase shifting network, the proposed antenna can
achieve a wide impedance bandwidth for VSWR ≤ 1.5 ranging from 1.1 to
1.8 GHz (about 48%) and a 3-dB AR bandwidth from 1.1 to 1.7 GHz.
Moreover, the 3-dB beamwidth is over 100° in this operating frequency
range. In this way, the antenna size is reduced to 0.42 λ 0 × 0.42 λ 0 × 0.16 λ 0, where
λ 0 is the wavelength at the center frequency in the free
space.
