A printed loop antenna for integration into a compact, outdoor WLAN access point (AP) is presented. The loop design has a one-wavelength, resonant structure with respect to the center operating frequency of the 2.4 GHz band and is formed on a 1.6-mm thick FR4 substrate. The antenna substrate is further stacked above a system (PCB) of an outdoor AP by a small distance. In this study, the proposed design integrates the system printed circuit board PCB serving as an efficient reflector for the loop into an internal AP antenna solution. The results showed that by feeding the proposed square loop at one corner and adding the tuning portion at the diagonal corner, the dual-polarized radiation in the two major planes and good impedance matching over the band can be attained. High gain, directional radiation patterns were also obtained.
2. Guo, Y. X. and K. M. Luk, "Dual-polarized dielectric resonator antennas," IEEE Antennas Propagat., Vol. 51, 1120-1124, 2003.
3. See, T. S. P. and Z. N. Chen, "Design of dual-polarization stacked arrays for ISM band applications," Microwave Opt. Technol. Lett., Vol. 38, 142-147, 2003.
4. Chang, F. S., H. T. Chen, K. C. Chaou, and K. L. Wong, "Dual-polarized probe-fed patch antenna with highly decoupled ports for WLAN base station," IEEE Antennas Propagat. Soc. Int. Symp. Dig., 101-109, Monterey, CA, USA, 2004.
5. Kraus, J. D. and R. J. Marhefka, Antennas: For All Applications, 3rd Ed., Chap. 9, 322-329, McGraw-Hill, New York, 2003.
6. NanoStation, Ubiquiti Networks, Inc., http://www.ubnt.com/products/nsm.php.
7. Su, S. W., T. C. Hong, and F. S. Chang, "Very compact coupledfed loop antenna for 2.4 GHz WLAN applications," Microwave Opt. Technol. Lett., Vol. 52, 1883-1887, 2010.
8. Morishita, H., Y. Kim, and K. Fujimoto, "Design concept of antennas for small mobile terminals and the future perspective," IEEE Antennas Propagat. Mag., Vol. 44, 30-34, 2002.
9. Chou, J. H. and S. W. Su, "Internal wideband monopole antenna for MIMO access-point applications in the WLAN/WiMAX bands ," Microwave Opt. Technol. Lett., Vol. 50, 1146-1148, 2008.
10. Su, S. W., "Very-low-profile monopole antennas for concurrent 2.4- and 5-GHz WLAN access-point applications," Microwave Opt. Technol. Lett., Vol. 51, 2614-2617, 2009.
11. Chang, F. S., Y. T. Liu, and S. W. Su, "A probe-fed patch antenna with a step-shaped ground plane for 2.4 GHz access point ," Microwave Opt. Technol. Lett., Vol. 51, 139-141, 2009.
12. CTIA authorized test laboratory, CTIA | The Wireless Association, http://www.ctia.org/business resources/certifcation/test labs/.
13. Volakis, J. L., Antenna Engineering Handbook, 4th Ed., Chap. 6, 16-19, McGraw-Hill, New York, 2007.