A planar, printed multiple-input multiple-output (MIMO) antenna for slim mobile handset is presented. The dual-antenna system, comprises two symmetric antenna elements, is printed on a printed circuit board (PCB) of mobile phone. Each antenna element consists of coupled-fed loop antenna. The loop antenna is formed by a quarter wavelength (at 762 MHz) meandered loop strip with end terminal short-circuited to the ground plane. A Tshaped protruded ground is deliberately designed to enhance the impedance matching and decoupled the two closely deposed antenna elements (distance between antenna elements are 0.03λ at 762 MHz). The integrity of the T-shaped decoupling structure and coupled-fed loop antenna array covers LTE700 (0.747 GHz−0.787 GHz) and WWAN (1.7 GHz-3.04 GHz) based on -6 dB reflection coefficient and achieves isolation between elements well below -10 dB over all the operating bands. The application platform is LTE700, GSM1700, GMS1800, UMTS, Wi-Fi, Bluetooth, LTE2300, and LTE2500 bands for the 2G/3G/4G mobile terminals. The effect of user proximity by considering the actual mobile environment is also studied in the form of total radiated power (TRP), specific absorption rate (SAR), diversity performances, and radiation performances. Finally, a prototype is fabricated and tested with network analyser. The measured results are found in good agreement with simulated ones.
2. Lee, B., E. J. Harackiewicz, and H. Wi, "Closely mounted mobile handset MIMO antenna for LTE 13 band application," IEEE Ant. and Wireless Propag. Lett., Vol. 13, 411-414, 2014.
3. Lee, J., Y.-K. Hong, S. Bae, G. S. Abo, W.-M. Seong, and G.-H. Kim, "Miniature long-term evolution (LTE) MIMO ferrite antenna," IEEE Ant. and Wireless Propag. Lett., Vol. 11, 603-606, 2011.
4. Baek, J. and J. H. Choi, "The design of a LTE/MIMO antenna with high isolation using a decoupling network," Microwave Opt. Tech. Lett., Vol. 56, No. 9, 2187-2191, 2014.
5. Yu, Y., G. Kim, J. Ji, and W. Seong, "A compact hybrid internal MIMO antenna for LTE application," European Conference on Antennas and Propagation, 1-2, Barcelona, Spain, Apr. 12-16, 2010.
6. Kim, B., Y. Park, H. Wi, M.-J. Park, Y. Choi, J. Lee, W. Jung, D. Kim, and B. Lee, "Isolation enhancement of USB dongleMIMO antenna in LTE700 band applications," IEEE Ant. and Wireless Propag. Lett., Vol. 11, 961-964, 2012.
7. Park, G., M. Kim, T. Yang, J. Byun, and A. S. Kim, "The compact quad-band handset antenna for LTE700 MIMO application," IEEE Antennas and Propagation Society International Symposium (APSURSI 2009), 1-4, Charleston, SC, Jun. 1-5, 2009.
8. Thomas, T., Y. V. B. Reddy, and K. Veeraswamy, "Small size printed antenna array for LTE/WWAN with LTE MIMO operation for mobile communication," 20th International Conference on Electronics and Communication Engineering, 64-68, Banglore, India, May 2012.
9. Wong, K.-L., T.-W. Kang, and M.-F. Tu, "Internal mobile phone antenna array for LTE/WWAN and LTE MIMO operations," Microwave Opt. Tech. Lett., Vol. 53, No. 7, 1569-1573, 2011.
10. Zhang, S., K. Zhao, Z. Ying, and S. He, "Adaptive quad-element multi-wideband antenna array for user-effective LTE MIMO mobile terminals," IEEE Trans. on Antennas and Propag., Vol. 61, No. 8, 4275-4283, 2013.
11. Yang, S., T. Jiang, J. L.-W. Li, and Y.-L. Ban, "Internal low profile multi band MIMO antenna for WWAN/LTE mobile phone applications," IEEE International Symposium Antennas and Propagation Society, 522-523, Orlando, FL, Jul. 7-13, 2013.
12. Diallo, A., C. Luxey, P. Le thuc, R. Staraj, and G. Kossiavas, "Study and reduction of the mutual coupling between two mobile phone PIFAs operating in the DCS1800 and UMTS bands," IEEE Trans. on Antennas Propag., Vol. 54, No. 11, 3063-3074, 2006.
13. Meshram, M. K., R. K. Animeh, A. T. Pimpale, and N. K. Nikolova, "A novel quad-band diversity antenna for LTE and Wi-Fi applications with high isolation," IEEE Trans. on Antennas Propag., Vol. 60, No. 9, 4360-4371, 2012.
14. Chen, S. C., Y. S. Wang, and S. J. Chuang, "A decoupling technique for increasing the port isolation between two strongly coupled antennas," IEEE Trans. on Antennas Propag., Vol. 56, No. 12, 3650-3658, 2008.
15. Zhang, S., S. N. Khan, and S. He, "Reducing mutual coupling for an extremely closely-packed tunable dual-element PIFA array through a resonant slot antenna formed in-between," IEEE Trans. on Antennas Propag., Vol. 58, No. 8, 2771-2776, 2010.
16. Ban, Y.-L., Z. X. Chen, Z. Chen, K. Kang, and L. W. Li, "Decoupled closely-spaced hepta-band antenna array for WWAN/LTE smartphone applications," IEEE Ant. and Wireless Propag. Lett., Vol. 13, 31-34, 2014.
17. Ban, Y.-L., S. Yang, Z. Chen, K. Kang, and J. L.-W. Li, "Decoupled planar WWAN antennas with T-shaped protruded ground for smartphone applications," IEEE Ant. and Wireless Propag. Lett., Vol. 13, 483-486, 2014.
18. Ansoft High Frequency Structure Simulator (HFSS), Online Available: http://www.ansoft.com.
19. Computer Simulation Technology Microwave Studio (CST MWS), Online Available: http://www.cst.com.
20. CTIA, CTIA certification test plan for mobile station over the air performance, Method of Measurement for Radiated RF Power and Receiver Performance, Washington, DC, Apr. 2005.
21. Durney, C. H., H. Massoudi, and M. F. Iskander, Radiofrequency Radiation Dosimetry Handbook, 4th Ed., Rep. USAF-SAM-TR-85-73, USAF School of Aerospace Medicine, Aerospace Medical Division (AFSC), Brook Air Force Base, Texas, Oct. 1986.
22. Taga, T., "Analysis for mean effective gain of mobile antennas in land mobile radio environments," IEEE Trans. Veh. Technol., Vol. 39, 117-131, 1990.
23. Singh, H. S., B. R. Meruva, G. K. Pandey, P. K. Bharti, and M. K. Meshram, "Low mutual coupling between MIMO antennas by using two folded shorting strips," Progress In Electromagnetics Research B, Vol. 53, 205-221, 2013.