Isolation improvement of UWB MIMO antenna utilising molecule fractal structure

Abstract

A compact four-element UWB MIMO antenna is proposed and its characteristics are investigated. The proposed antenna has a hexagon molecule-shaped fractal structure as its radiating element. The antenna elements are placed orthogonally to each other in order to yield good isolation, without any additional decoupling structure. The band rejection in WLAN band is attained by etching a C-shaped slot on each radiating element. The antenna has a compact size of 40 × 40 × 1.6 mm 3 and exhibits stable omni-directional radiation pattern. In addition, it shows an acceptable impedance bandwidth (S 11 < −10 dB) in the range 2.4-10.6 GHz with an isolation better than −20 dB over the UWB range. The performance of the proposed antenna is calculated in terms of antenna characteristics and MIMO parameters. The isolation level in-between the elements is found to be reasonable for MIMO application. The simulated and measured results are in good accord which makes the antenna a suitable candidate for massive MIMO and high-density packaging applications.

A Compact U-Shaped Uwb-Mimo Antenna With Novel Complementary Modified Minkowski Fractal for Isolation Enhancement

“…Many fractal UWB-MIMO antennas have been reported in the past [13][14][15][16][17][18][19][20][21][22]. Koch [13], selfsimilar [14], complementary Sierpinski gasket [15], modified Sierpinski carpet [16], and hybrid Sierpinski Koch [17] shaped two-element fractal monopole UWB-MIMO antennas are reported in [13][14][15][16][17].…”

“…Koch [13], selfsimilar [14], complementary Sierpinski gasket [15], modified Sierpinski carpet [16], and hybrid Sierpinski Koch [17] shaped two-element fractal monopole UWB-MIMO antennas are reported in [13][14][15][16][17]. Koch [18], hexagonal molecule shaped [19], and Sierpinski Knopp [20] shaped four-element fractal monopole UWB-MIMO antennas are reported in [18][19][20]. In the above-reported MIMO antennas, fractal structures are used on patch sides to achieve miniaturization and wideband characteristics.…”

Miniaturized CPW-fed UWB-MIMO antennas with decoupling stub and enhanced isolation

“…In [19], uniplanar MIMO-UWB design having two circular radiating elements fed with a modified orthogonal ACS with a diagonally rectangular stub in between the radiators of size 28.5 × 28.5 mm 2 , operating over the frequency range from 2.66 to 11.08 GHz is proposed. A quad-element hexagon-molecule-shaped UWB fractal MIMO antenna having a half-circular partial ground of size 40 × 40 mm 2 with an inter-port isolation greater than 20 dB and operating over the frequency range from 2.4 to 10.6 GHz having an impedance bandwidth of 9 GHz is investigated in [20]. A quarter-wave-fed, bi-radiating elements E-slot semi-circular MIMO antenna of size 42 × 30 mm 2 for UWB applications is proposed in [21], having an inter-port isolation of greater than 20 dB and operating over the frequency range from 3.04 to 10.87 GHz.…”

Opportunistic control of fractal‐based MIMO antenna for sub‐6‐GHz 5G applications

“…A fractal compactness octagonal structure with frequency 3.1–10.6 GHz with band rejection for wireless LAN systems, 7 two closely spaced dual‐band MIMO design using decoupling structure, 8 using the superstrate of EMNZ patch‐type antenna for gain as well as isolation enhancement, 9 a novel technique of Sierpinski Knopp structure using four elements with notch band characteristics 10 designed for dual‐band MIMO systems. The technique of defect in ground structure (DGS) used for interference inherent MIMO has been designed 11 for UWB systems, MIMO antenna was designed for portable devices and wireless LAN rejection, 12,13 using the structure of ohm‐type symbol and structure of L‐shape designed for reduction of mutual coupling, 14 a mushroom structure using metamaterial designed four elements for isolation enhancement MIMO system, 15 a compact novel structure of kotch fractal radiator for band rejection of wireless LAN systems, 16 using the structure of F‐shaped stubs involved, 17 for WLAN rejection characteristics of 4 × 4 MIMO radiator was designed, 18 the technique of neutralization line method for mutual coupling reduction of Wang‐shaped structure, 19 for improvement of the parameter isolation using the technique of molecule fractal structure utilization is designed in 20 . To obtain the low mutual coupling, the technique used periodic‐type multilayered EBG structure, 21 for the applications of wireless services designed UWB MIMO packaging system, 22 and finally, a tree‐like structure of diversity/MIMO radiator for wideband isolation improvement 23 was designed.…”