Low Coupling Miniaturized MIMO Antenna for Quad Band Application

Researchers have recently focused on designing compact MIMO antenna systems for wireless communication with ultra-wideband-however, miniaturization results in weak isolation between antenna elements. Therefore, several isolation enhancement techniques, such as slits, elliptical slots, EBG structure, neutralization lines, decoupling structures, stubs, DGS, and SRR are applied. A compact multi-band and low-coupling antenna is proposed for short-range wireless communication. The design comprises two symmetrical monopole antennae with T-shape stubs to improve the isolation > 18 dB over the 3.1-12GHz. The dimensions of the antenna are 44 x 20 x 1.53 mm3. The quad-band (S11< -10 dB) at 3.25-3.85GHz, 5.10-5.65GHz, 8.60-8.90GHz, and 9.55-11.80GHz is achieved with a mutual coupling (S21) of -22.0dB, -21.36dB, -35dB, and -18dB respectively. The antenna provides effective coverage of four frequency bands with low electromagnetic interference. The antenna with high bandwidth is available for high-frequency applications in the X band. A finite element method solver such as Ansys High-Frequency Structure Simulator (HFSS) software for the design of recommended antennae is preferred. The fabricated antenna was tested using a vector network analyzer to measure S parameters such as S11, S21, and VSWR. The envelope correlation coefficient < .0001, DG > 9.90 dB, CCL < 0.0005 bps/Hz, and TARC <-10dB is obtained over the working bandwidth of the antenna. The actual and measured outcomes approximately match, with a slight deviation due to fabrication, copper, and conductor loss. Therefore, the recommended antenna is the ultimate candidate for multi-band application.