volume | PIER Journals

Abstract

In this paper, a wideband polarization diversity multi-input multioutput (MIMO) antenna system is proposed. The structure of the proposed antenna consists of four wideband coplanar waveguide (CPW)-fed monopole antennas with a common ground plane and radiated element. The simulated and measured -10 dB impedance bandwidth is 20% (2.25-2.75 GHz), which covers WiFi (2.4 GHz) and LTE (2.6 GHz) frequency bands. The MIMO antenna system is applied to both an indoor and outdoor wireless access point (WAP) at the covered frequency bands. Due to the common structure of elements in the proposed MIMO antenna, an acceptable mutual coupling between the antennas ports is critical. Hence, a new parasitic element structure is presented to improve mutual coupling between the antenna ports. Acceptable values for the coupling coefficient (<-14 dB) are achieved by adding the parasitic element. The presented antenna system provides a nearly omnidirectional radiation pattern with an orthogonal mode of linear polarization. The results show a polarization diversity gain of 10 dB and an envelope correlation coefficient of less than 0.2. Moreover, each antenna port possesses peak gains of 5.33-6.97 dBi and efficiencies of 51.5-57%. A comparison between the simulation results and experimental measurements reveals good agreement between the two, confirming the validity of the proposed design.

1. Ban, Y.-L., et al. "4G/5G multiple antennas for future multi-mode smartphone application," IEEE Access, Vol. 4, 2981-2988, 2016.
doi:10.1109/ACCESS.2016.2582786

2. Wang, C.-J. and C.-M. Lin, "A CPW-fed open-slot antenna for multiple wireless communication systems," IEEE Antennas Wireless Propag. Lett., Vol. 11, 620-623, 2012.
doi:10.1109/LAWP.2012.2203289

3. Liu, W.-C., "Broadband dual frequency meandered CPW-fed monopole antenna," Electron Lett., Vol. 40, 1319-1320, 2004.
doi:10.1049/el:20045952

4. Lu, W.-C., "Broadband dual frequency cross-shaped slot CPW-fed monopole antenna for WLAN operation," Microwave Opt. Tech. Lett., Vol. 46, 353-355, 2005.
doi:10.1002/mop.20985

5. Moradi Kordalivand, A., T.-A. Rahman, and M. Khalily, "Common elements wideband MIMO antenna system for WiFi/LTE access-point applications," IEEE Antennas Wireless Propag. Lett., Vol. 13, 1601-1604, 2014.
doi:10.1109/LAWP.2014.2347897

6. Pan, Y., et al. "Evaluation of dual-polarised triple-band multibeam MIMO antennas for WLAN/WiMAX application," IET Microwaves, Antennas & Propagation, Vol. 11, 1469-1475, 2017.
doi:10.1049/iet-map.2016.1101

7. Chen, S.-C. and C.-S. Fu, "Switchable long-term evolution/ wireless wide area network/ wireless local area network multiple-input and multiple-output antenna system for laptop computer," IEEE Access, Vol. 5, 9857-9865, 2017.
doi:10.1109/ACCESS.2017.2705739

8. Li, J.-F., Q.-X. Chu, and T.-G. Huang, "A compact wideband MIMO antenna with two novel bent slits," IEEE Trans. Antennas Propagat., Vol. 60, No. 2, 482-489, Feb. 2012.
doi:10.1109/TAP.2011.2173452

9. Sonkki, M., E. Antonino-Daviu, M. Cabedo-Fabres, M. Ferrando-Bataller, and E. T. Salonen, "Improved planar wideband antenna element and its usage in a mobile MIMO system," IEEE Antennas Wireless Propag. Lett., Vol. 11, 826-829, 2012.
doi:10.1109/LAWP.2012.2208615

10. WiMAX Broadband Wireless Access, Wi-fiplanet.com, retrieved Mar. 2008.

11. Li, R. L., X. L. Quan, Y. H. Cui, and M. M. Tentzeri, "Directional triple-band planar antenna for WLAN/WiMax access points," Electron Lett., Vol. 48, No. 6, 2012.
doi:10.1049/el.2011.3448

12. Su, S.-W., "High-gain dual-loop antennas for MIMO access points in the 2.4/5.2/5.8 GHz bands," IEEE Antennas Wireless Propag. Lett., Vol. 58, No. 7, 2412-2419, 2010.
doi:10.1109/TAP.2010.2048871

13. Medeiros, C. R., E. B. Lima, J. R. Costa, and C. A. Fernandes, "Wideband slot antenna for WLAN access points," IEEE Antennas Wireless Propag. Lett., Vol. 9, 79-82, 2010.
doi:10.1109/LAWP.2010.2043332

14. Fernandez, S. C. and S. K. Sharma, "Multiband printed meandered loop antennas with MIMO implementations for wireless routers," IEEE Antennas Wireless Propag. Lett., Vol. 12, 96-99, 2013.
doi:10.1109/LAWP.2013.2243104

15. Moradi, A., T.-A. Rahman, C. Y. Leow, and S. Ebrahimi, "Dual-polarized MIMO antenna system for WiFi and LTE wireless access point application," Int. J. Commun. Syst., Vol. 30, 2017.

16. Kim, S. J., H. S. Lee, and Y.-S. Kim, "A CPW-fed staircase monopole UWB antenna with bandnotched frequency in the WLAN band," Microw. Opt. Technol. Lett., Vol. 49, No. 10, 2545-2547, 2007.
doi:10.1002/mop.22775

17. Azarmanesh, M., S. Soltani, and P. Lotfi, "Design of an ultra-wideband monopole antenna with WiMAX, C and wireless local area network band notches," IET Microw. Antennas Propag., Vol. 5, No. 6, 728-733, 2011.
doi:10.1049/iet-map.2010.0148

18. Zaker, R. and A. Abdipour, "A very compact ultrawideband printed omnidirectional monopole antenna," IEEE Antennas Wireless Propag. Lett., Vol. 9, 471-473, 2010.
doi:10.1109/LAWP.2010.2050852

19. Kim, K.-H., Y.-J. Cho, S.-H. Hwang, and S.-O. Park, "Band-notched UWB planar monopole antenna with two parasitic patches," Electron Lett., Vol. 41, No. 14, 2005.
doi:10.1049/el:20051090

20. Zhou, X., X.-L. Quan, and R.-L. Li, "Dual-band WLAN diversity antenna system with high portto- port isolation," IEEE Antennas Wireless Propag. Lett., Vol. 11, 244-247, 2012.

21. Yang, F. and Y. Rahmat-Samii, "Microstrip antennas integrated with EBG structures: A low mutual coupling design for array applications," IEEE Trans. Antennas Propagat., Vol. 51, 2936-2946, Oct. 2003.

22. Ayatollahi, M., Q. Rao, and D. Wang, "A compact, high isolation and wide bandwidth antenna array for long term evolution wireless devices," IEEE Trans. Antennas Propagat., Vol. 60, No. 10, 4960-4963, Oct. 2012.
doi:10.1109/TAP.2012.2207312

23. Li, J.-F., Q.-X. Chu, Z.-H. Li, and X.-X. Xia, "Compact dual band-notched UWB MIMO antenna with high isolation," IEEE Trans. Antennas Propagat., Vol. 61, No. 9, 4759-4766, Sep. 2013.
doi:10.1109/TAP.2013.2267653

24. Colburn, J. S., Y. Rahmat-Samii, M. A. Jensen, and G. J. Pottie, "Evaluation of personal communications dual-antenna handset diversity performance," IEEE Trans. Antennas Propagat., Vol. 47, No. 3, 737-746, Aug. 1998.

Dr. Alireza Moradi

Prof. Razali Ngah

Dr. Mohsen Khalily