A compact circularly polarized (CP) printed antenna for global positioning system (GPS) is proposed. The antenna adopts a two-layered stacked structure, in which a diagonally positioned rectangular patch is used as the driven part and capacitively loaded patch-based crossed dipoles are used as the main radiators. Good impedance matching is obtained conveniently by using magnetic-coupling feeding technique, and antenna size reduction is realized by using capacitively-loaded structure (50% size reduction in comparison with the conventional half-wave dipole antennas). A prototype of the antenna with the size of 46 mm × 46 mm is fabricated and tested. Good agreement is achieved between the simulated and measured results, which shows that the impedance bandwidth defined by 10 dB return loss is 34.8 MHz. In addition, the 3 dB-axial-ratio bandwidth is 8 MHz, and the antenna gain is about 7 dB.
2. Sudha, T., T. S. Vedavathy, and N. Bhat, "Wideband single-fed circularly polarised patch antenna," Electron. Lett., Vol. 40, No. 11, 2004.
3. Wong, H., P.-Y. Lan, K.-M. Mak, and K.-M. Luk, "Small circularly polarised folded patch antenna," Electron. Lett., Vol. 41, No. 25, 2005.
4. Yang , F. and Y. Rahmat-samii, "A single layer dual band circularly polarized microstrip antenna for GPS applications," IEEE Antennas Propagat. Society International Symposium, Vol. 4, 720-723, 2002.
5. Yu, A. , F. Yang, and A. Z. Elsherbeni, "A dual band circularly polarized ring antenna based on composite right and left handed metamaterials," Progress In Electromagnetics Research, Vol. 78, 73-81, 2008.
6. Bahl, I. J., P. Bhartia, A. Ittipiboon, and R. Garg, Microstrip Antenna Design Handbook,, Artech House, 2001.
7. Lin, C.-C. , P. Jin, and R. W. Ziolkowski, "Multi-functional, magnetically-coupled, electrically small, near-field resonant parasitic wire antennas," IEEE Trans. Antennas Propag., Vol. 59, 714-724, 2010.