A Compact Quad Bands Patch Antenna And MIMO Antenna System For Wireless Communications

Abstract

This work presents a compact quad band MIMO antenna for wireless communication systems that is developed and investigated. The proposed MIMO antenna structure is composed of two adjacent identical antenna elements which are fed through microstrip lines. The single element of the MIMO system is the spiral monopole antenna. The quad bands are attained by introducing circular ring slots in a circular patch antenna to get a new form of spiral antenna. The proposed single antenna has a dimensions of 14×18 mm 2 . The results show that the single antenna element operates at (1.39), (2.5), (3.63) and 4.15GHz for WiMAX and C band. It is also observed from the results that the antenna offers good radiation characteristics for the frequency band of interest. Furthermore, a 2 × 2 MIMO antenna is designed by utilizing the polarization diversity technique. The two spiral elements are placed orthogonally and an inverted L-shaped are placed between them to improve the isolation performance. Moreover, the proposed MIMO antenna operates (1.39), (2.5), (3.52) and 4.02 GHZ for WiMAX and C band applications. The isolation of the proposed antenna is higher than 15?dB, and the antenna maintains relatively stable radiation characteristics and gain, as well as a lower envelope correlation coefficient(ECC?less than 0.2).