A co-designed compact dual-band filter-antenna suitable to be embedded inside a wireless access point (AP) in the 2.45/5.2-GHz wireless local area network (WLAN) bands is presented. The proposed filter-antenna comprises a loop-loaded dual-band monopole radiator and a microstrip dual-band pseudo-interdigital bandpass filter. The monopole consists of a uniform width monopole, two identical capacitively loaded magnetic resonators and a top loaded loop. The two magnetic resonators are loaded at the center of the monopole for dual-band operation and the rectangular loop loaded at the top is involved for miniaturization. Instead of using the traditional 50Ω interfaces, the impedance between the filter and antenna is optimized to improve the performance. The filter-antenna and the system circuit board of an AP share the same substrate and ground plane. In this case the design can fully integrate the circuit board of the AP into an internal filter-antenna solution. The proposed filter-antenna provides good selectivity and rejection in out of band regions and omni-directional radiation patterns within the two desired bands. The measured results show good agreement with the simulated ones.
2. Barbarino, S. and S. Consoli, "UWB circular slot antenna provided with an inverted-L notch filter for the 5 GHz WLAN band," Progress In Electromagnetics Research, Vol. 104, 1-13, 2010.
3. Lee, J.-H., N. Kidera, S. Pinel, J. Laskar, and M.-M. Tentzeris, "Fully integrated passive front-end solutions for a V-band LTCC wireless system," IEEE Antennas Wireless Propag. Lett., Vol. 5, 285-288, 2007.
4. Mandal, M.-K., Z.-N. Chen, and X.-M. Qing, "Compact ultra-wideband filtering antennas on low temperature co-fired ceramic substrate," Asia Pacific Microwave Conference, 2084-2087, Dec. 2009.
5. Wong, S.-W., T.-G. Huang, C.-X. Mao, Z.-N. Chen and Q.-X. Chu, "Planar filtering ultra-wideband (UWB) antenna with shorting pins," IEEE Trans. Antennas Propag., Vol. 61, 948-953, 2013.
6. Zhu, Y., F.-S. Zhang, R. Zou, Y.-C. Jiao, and Q.-C. Zhou, "Compact ultra-wideband monopole antenna with novel filter," Journal of Electromagnetic Waves and Applications, Vol. 25, No. 14-15, 2066-2075, 2011.
7. Troubat, M., S. Bila, M. Thevenot, D. Baillargeat, T. Monediµere, S. Verdeyme, and B. Jecko, "Mutual synthesis of combined microwave circuits applied to the design of a filter-antenna subsystem," IEEE Trans. Microw. Theory Tech., Vol. 55, No. 6, 1182-1189, 2007.
8. Quere, Y., C. Quendo, H.-W. El, and C. Person, "A global synthesis tool and procedure for filter-antenna co-design," 15th International Symposium on Antenna Technology and Applied Electromagnetics, 1-4, 2012.
9. Wu, W.-J., Y.-Z. Yin, S.-L. Zuo, Z.-Y. Zhang, and J.-J. Xie, "A new compact filter-antenna for modern wireless communication systems," IEEE Antennas Wireless Propag. Lett., Vol. 10, 1131-1134, 2011.
10. Zuo, S.-L., W.-J. Wu, and Z.-Y. Zhang, "A simple filter-antenna with compact size for WLAN application," Progress In Electromagnetics Research Letters, Vol. 39, 17-26, 2013.
11. Demir, V., C.-W. P. Huang, and A. Elsherbeni, "Novel dual-band WLAN antennas with integrated band-seltct filter for 802.11 a/b/g WLAN radios in portable devices," Microwave Opt. Technol. Lett., Vol. 49, No. 8, 1868-1872, 2007.
12. Zayniyev, D. and D. Budimir, "Dual-band microstrip antenna filter for wireless communications," IEEE Antennas and Propagation Society International Symposium (APSURSI), 1-4, 2010.
13. Naeem, U., S. Bila, S. Verdeyme, M. Thevenot, and T. Monediµere, "A compact dual band filter-antenna subsystem for 802.11 WiFi applications," Wireless Technology Conference (EuWIT), 181-184, 2010.
14. Xu, K.-D., Y.-H. Zhang, C.-L. Zhuge, and Y. Fan, "Miniaturized dual-band bandpass filter using short stub-loaded dual-mode resonators," Journal of Electromagnetic Waves and Applications, Vol. 25, No. 16, 2264-2273, 2011.
15. Sagawa, M., M. Makimoto, and S. Yamashita, "Geometrical structures and fundamental characteristics of microwave stepped-impedance," IEEE Trans. Microw. Theory Tech., Vol. 45, No. 7, 1078-1085, 1997.