A compact 2×1 multiple input multiple output (MIMO) antenna system is designed to operate in the LTE band 40 (2.3-2.4) GHz. The proposed antenna consists of two circular patches fed using microstrip line. The antenna was initially designed to resonate at 5 GHz. Size reduction of 55.17% compared to conventional patch antenna is obtained after the inclusion of circular complementary split ring resonator (CSRR) in the ground plane. The resonating frequency was shifted to 2.34 GHz, there by the board size is compact (50×25×1.6 mm3). The designed antenna covers a bandwidth of 2.3 to 2.374 GHz with a maximum return loss of -27 dB at 2.34 GHz and isolation of -33.5 dB between the ports. The simulated correlation coefficient is approximately zero, and the total active reflection coefficient is 0.142 at the resonating frequency which are within the acceptable limits. The realized gain for the antenna is -8.9 dB.
2. Larmo, A., et al., "The LTE link-layer design," IEEE Commun. Mag., Vol. 47, No. 4, 52-59, Apr. 2009.
3. Zhang, Y. and B. Niu, "Compact Ultrawideband (UWB) slot antenna with wideband and high isolation for MIMO applications," Progress In Electromagnetics Research C, Vol. 54, 9-16, 2014.
4. Schaubert, D. and K. Yngvesson, "Experimental study of a microstrip array on high permittivity substrate," IEEE Transactions on Antennas and Propagation, Vol. 34, No. 1, 92-97, 1986.
5. Herscovici, N., M. F. Osorio, and C. Peixeiro, "Miniaturization of rectangular microstrip patches using genetic algorithms," IEEE Antennas and Wireless Propagation Letters, Vol. 1, No. 1, 94-97, 2002.
6. Bokhari, S. A., et al., "A small microstrip patch antenna with a convenient tuning option," IEEE Transactions on Antennas and Propagation, Vol. 44, No. 11, 1521-1528, 1996.
7. Latif, S. I., L. Shafai, and C. Shafai, "An engineered conductor for gain and efficiency improvement of miniaturized microstrip antennas," IEEE Antennas and Propagation Magazine, Vol. 55, No. 2, 77-90, 2013.
8. Chow, Y. L., K. L. Wan, and T. K. Sarkar, "Patch antenna miniaturizing with a shorting pin near the feed probe-its physical mechanism and the design on Smith Chart," 2001 Asia-Pacific Microwave Conference, APMC 2001, Vol. 3, IEEE, 2001.
9. Kuo, J.-S. and K.-L. Wong, "A compact microstrip antenna with meandering slots in the ground plane," Microwave and Optical Technology Letters, Vol. 29, No. 2, 95-97, 2001.
10. Huang, J., "The finite ground plane effect on the microstrip antenna radiation patterns," IEEE Transactions on Antennas and Propagation, Vol. 31, No. 4, 649-653, 1983.
11. Liu, J., W.-Y. Yin, and S. He, "A new defected ground structure and its application for miniaturized switchable antenna," Progress In Electromagnetics Research, Vol. 107, 115-128, 2010.
12. Khan, M. U., M. S. Sharawi, and R. Mittra, "Microstrip patch antenna miniaturisation techniques: A review," IET Microwaves, Antennas & Propagation, Vol. 9, No. 9, 913-922, Jun. 2015.
13. Dong, Y., H. Toyao, and T. Itoh, "Design and characterization of miniaturized patch antenna loaded with complementary split ring resonators," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 2, 772-785, Feb. 2012.
14. Ouedraogo, R. O., E. J. Rothwell, A. R. Diaz, K. Fuchi, and A. Temme, "Miniaturization of patch antennas using a metamaterial-inspired technique," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 5, 2175-2182, May 2012.
15. Khan, M. U. and M. S. Sharawi, "A compact 8-element MIMO antenna system for 802.11ac WLAN applications," International Workshop on Antenna Technology, (IWAT), 91-94, 2013.
16. Asieh, H., J. Nourinia, and C. Ghobadi, "Mutual coupling reduction between very closely spaced patch antennas using low-profile Folded Split-Ring Resonators (FSRRs)," IEEE Antennas and Wireless Propagation Letters, Vol. 10, 862-865, IEEE, 2011.
17. Saraswat, R. K. and M. Kumar, "Miniaturized slotted ground UWB antenna loaded with metamaterial for WLAN and WiMAX applications," Progress In Electromagnetics Research B, Vol. 65, 65-80, 2016.
18. Liu, L., S. W. Cheung, and T. Yuk, "Compact MIMO antenna for portable UWB applications with band-notched characteristic," IEEE Transactions on Antennas and Propagation, Vol. 63, No. 5, 1917-1924, 2015.
19. Xia, R., S. Qu, Q. Jiang, P. Li, and Z. Nie, "An efficient decoupling feeding network for twoelement microstrip antenna array," IEEE Transactions on Antennas and Wireless Propagation Letters, Vol. 14, 871-874, 2015.
20. Lin, K.-C., C.-H. Wu, C.-H. Lai, and T.-G. Ma, "Novel dual-band decoupling network for twoelement closely spaced array using synthesized microstrip lines," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 11, 5118-5128, 2012.
21. Chen, W.-J. and H.-H. Lin, "LTE700/WWAN MIMO antenna system integrated with decoupling structure for isolation improvement," Antennas and Propagation Society International Symposium (APSURSI), 689-690, IEEE, 2014.
22. Wang, H., D. G. Fang, and X. L. Wang, "Mutual coupling reduction between two microstrip patch antennas by using the parasitic elements," Asia-Pacific Microwave Conference, APMC 2008, 1-4, IEEE, 2008.
23. Margaret, D. H., M. R. Subasree, S. Susithra, S. S. Keerthika, and B. Manimegalai, "Mutual coupling reduction in MIMO antenna system using EBG structures," International Conference on Signal Processing and Communications (SPCOM), 1-5, IEEE, 2012.
24. Islam, M. T. and M. S. Alam, "Compact EBG structure for alleviating mutual coupling between patch antenna array elements," Progress In Electromagnetics Research, Vol. 137, 425-438, 2013.
25. Yu, Y., et al., "Dual-frequency two-element antenna array with suppressed mutual coupling," International Journal of Antennas and Propagation, 1-6, 2014.
26. Wu, Y.-T. and Q.-X. Chu, "Dual-band multiple input multiple output antenna with slitted ground," Microwaves, Antennas & Propagation, IET 8.13, 1007-1013, 2014.
27. Su, S.-W., C.-T. Lee, and F.-S. Chang, "Printed MIMO-antenna system using neutralization-line technique for wireless USB-dongle applications," IEEE Transactions on Antennas and Propagation, Vol. 60, No. 2, 456-463, 2012.
28. Zhang, S. and G. Pedersen, "Mutual coupling reduction for UWB MIMO antennas with a wideband neutralization line," IEEE Antennas and Wireless Propagation Letters, Vol. 15, 166-169, 2016.
29. Ren, Y.-H., et al., "A wideband dual-polarized printed antenna based on complementary split-ring resonators," IEEE Antennas and Wireless Propagation Letters, Vol. 14, 410-413, 2015.
30. Baena, J. D., J. Bonache, F. Martin, R. Marques, F. Falcone, T. Lopetegi, M. A. G. Laso, J. Garcia, I. Gil, and M. Sorolla, "Equivalent-circuit models for split-ring resonators and complementary splitring resonators coupled to planar transmission lines," IEEE Transactions on Microwave Theory and Techniques, Vol. 53, No. 4, 1451-1461, Apr. 2005.
31. Wahid, A., M. Sreenivasan, and P. H. Rao, "CSRR loaded microstrip array antenna with low sidelobe level," IEEE Antennas and Wireless Propagation Letters, Vol. 14, 1169-1171, 2015.
32. Cheng, X., D. E. Senior, C. Kim, and Y. Yoon, "A compact omnidirectional self-packaged patch antenna with complementary split-ring resonator loading for wireless endoscope applications," IEEE Antennas and Wireless Propagation Letters, Vol. 10, 1532-1535, 2011.
33. Ziolkowski, R. W., "Design, fabrication and testing of double negative metamaterials," IEEE Transactions on Antennas and Propagation, Vol. 51, No. 7, 1516-1529, Jul. 2003.
34. Rothwell, E. J., et al., "Analysis of the Nicolson-Ross-Weir Method for characterizing the electromagnetic properties of engineered materials," Progress In Electromagnetics Research, Vol. 157, 31-47, 2016.
35. Wirgin, A., "Retrieval of the frequency-dependent effective permeability and permittivity of the inhomogeneous material in a layer," Progress In Electromagnetics Research B, Vol. 70, 131-147, 2016.
36. Luo, C.-M., J.-S. Hong, and L.-L. Zhong, "Isolation enhancement of a very compact UWBMIMO slot antenna with two defected ground structures," IEEE Transactions on Antennas and Propagation, Vol. 14, No. 2, 1766-1769, Apr. 2015.
37. Sharawi, M. S., M. U. Khan, A. B. Numan, and D. N. Aloi, "A CSRR loaded MIMO antenna system for ISM band operation," IEEE Transactions on Antennas and Propagation, Vol. 61, No. 8, 4265-4274, Aug. 2013.
38. Choukiker, Y. K., S. K. Sharma, and S. K. Behera, "Hybrid fractal shape planar monopole antenna covering multiband wireless communications with MIMO implementation for handheld mobile devices," IEEE Transactions on Antennas and Propagation, Vol. 62, No. 3, 1483-1488, Mar. 2014.