A multiarm curl antenna for GPS applications

Abstract

A single-feed dual-band antenna with wide-beam circularly polarized (CP) radiation is introduced for application in the global positioning system (GPS). The primary radiating element is a planar multiarm curl antenna. The dual-band operation is achieved by dividing the arms of the antenna into two branches of different lengths. To generate CP radiation, the radiator is fed by double vacant-quarter printed rings, which allows direct matching of the antenna to a single 50 Ω coaxial line. To enable unidirectional CP radiation and improve the 3 dB axial ratio (AR) beamwidth, the planar multiarm curl radiator is backed by a rectangular cavity-backed reflector. The final design, with an overall GPS-L2 frequency size of approximately λ_o/2.45 × λ_o/2.45 × λ_o/8, resulted in a |S₁₁|<–10 dB bandwidth of 1.221–1.282 GHz (4.9%) and 1.546–1.660 GHz (7.1%) and a 3 dB AR bandwidth of 1.212–1.240 GHz (2.2%) and 1.560–1.590 GHz (1.9%). Furthermore, it showed excellent right-hand CP (RHCP) radiation at both operating bands, namely wide beamwidth, similar gain, a high front-to-back ratio, and high radiation efficiency.

Keywords:

• multiarm curl
• short Archimedean spiral
• single feed
• vacant-quarter printed ring
• circular polarization
• global positioning system

Acknowledgement

This work was supported by ICT R&D Program of MSIP/IITP [14-911-01-001].