This paper presents a new quasi-metallic-wall technique for improving the gain of CB-CPW single antenna and arrays. This technique allows reducing the surface wave losses of the CB-CPW antennas, which decreases the antenna radiation efficiency. It consists on including pins as quasi-metallic wall between the upper and lower ground planes in the CB-CPW antenna structure. To validate the proposed approach, a CB-CPW-slot antenna fed through an inductive coupled CPW-line operating at 5.8 GHz is considered. This approach allows to increase the antenna efficiency from 70% to 95% around the operating frequency. The antenna gain achieves then an improvement of 2 dBi. Also, an antenna array is designed and the pins technique is also applied to prove its applicability for the array case. An efficiency increase from 64% to 95% was achieved. Both single antenna and antenna array withpins were fabricated and measured. A good agreement between numerical and experimental results was obtained.
2. Jiao, J.-J., G. Zhao, F.-S. Zhang, H.-W. Yuan, and Y.-C. Jiao, "A broadband CPW-fed T-shape slot antenna," Progress In Electromagnetics Research, Vol. 76, 237-242, 2007.
3. Saed, M. A., "Broadband CPW-fed planar slot antennas with various tuning stubs," Progress In Electromagnetics Research, Vol. 66, 199-212, 2006.
4. Rao, Q., T. A. Denidni, A. R. Sebak, and R. H. Johnston, "On improving impedance matching of a CPW FED low permittivity dielectric resonator antenna," Progress In Electromagnetics Research, Vol. 53, 21-29, 2005.
5. Liu, W. C. and C. F. Hsu, "CPW-FED notched monopole antenna for UMTS/IMT-2000/WLAN applications," Journal of Electromagnetic Waves and Applications, Vol. 21, No. 6, 841-851, 2007.
6. Chen, Y. B., Y. C. Jiao, F. S. Zhang, and H. W. Gao, "A novel small CPW-fed T-shaped antenna for MIMO system applications," Journal of Electromagnetic Waves and Applications, Vol. 20, No. 14, 2027-2036, 2006.
7. Liu, W. C. and Y. T. Kao, "CPW-fed compact meandered strip antenna on a soft substrate for dualband WLAN communication," Journal of Electromagnetic Waves and Applications, Vol. 21, No. 7, 987-995, 2007.
8. Shigesawa, H., M. Tsuji, and A. Oliner, Conductor-backed slot line and coplanar waveguide: Dangers and full-wave analyzes, Proc. IEEE MTT-S Int. Microwave Symp. Dig., 199-202, 1998.
9. Haydl, W. H., "On the use of vias in conductor-backed coplanar circuits," IEEE Trans. Microwave Theory and Techniques, Vol. 50, No. 6, 2059-2074, 2002.
10. Jahagirdar, D. R. and R. D. Stewart, "Non-leaky conductorbacked coplanar waveguide-fed microstrip patchan tenna," IEEE Microwave and Guided Wave Letters, Vol. 8, No. 3, 115-117, 1998.
11. Lan, I. C. and P. Hsu, Parallel-plate slot array fed by conductorbacked coplanar waveguide, Proc. 2005 European Microwave Conference, Vol. 1, No. 10, 473-476, 2005.
12. Qiu, M. and G. V. Eleftheriades, "Highly efficient unidirectional twin arc-slot antennas on electrically thin substrates," IEEE Trans. Microwave Theory Tech., Vol. 52, No. 1, 53-58, 2004.
13. Nedil, M., A. T. Denidni, and L. Talbi, Design of a broadband slot antenna fed by CPW for wireless application at 5.8 GHz, Proc. Vehicular Technology Conference, Vol. 1, No. 5, 18-21, 2004.
14. Advanced Design System 2004, Agilent Technologies, Agilent Technologies, Palo Alto.
15. Ansoft HFSS version 9.0, Ansoft Corporation, Ansoft Corporation, Pittsburgh.
16. Yang, F. and Y. Rahmat-Samii, "Microstrip antennas integrated withelectromagn teic band-gap (EBG) structures: A low mutual coupling design for array applications," IEEE Trans. on Antennas and Prop., Vol. 47, No. 11, 2936-2946, 2003.
17. Iluz, Z., R. Shavit, and R. Bauer, "Microstrip antenna phased array withelectromagnetic bandgap substrate," IEEE Trans. on Antennas and Prop., Vol. 52, No. 06, 1446-1453, 2004.
18. Giauffret, L., J.-M. Laheurte, and A. Papiernik, "Study of various shapes of the coupling slot in CPW-fed microstrip antennas," IEEE Trans. Antennas and Prop., Vol. 45, No. 4, 642-647, 1997.
19. Simons, R. N., Coplanar Waveguide Circuits, Components, and Systems, Wiley-Interscience, John Wiley and Sons Inc., 2001.