Tri-band circularly polarized annular slot antenna for GPS and CNSS applications

Abstract

A novel single-feed tri-band circularly polarized (CP) annular slot antenna is presented. The antenna structure is composed of two nonconcentric annular slots that are fed by an Lshaped series step impedance microstrip line configuration. The proposed antenna is designed to operate at the L1 and L2 bands of the global positioning system and the operating band of the compass navigation satellite system. Compared to the most of the previously reported tri-band CP antenna structure, the proposed antenna has low profile, compact size, and easy fabrication on the single-layer PCB. The measured results show that the impedance bandwidths are good for all bands. The axial ratio bandwidth and radiation patterns are also measured at the three resonant frequencies. The proposed compact tri-band CP antenna design is suitable for mounting onto the mobile communication devices and portable positioning systems. © 2012 Taylor & Francis.