Design of inverted L-shape & ohm symbol inserted MIMO antenna to reduce the mutual coupling

Abstract

A compact antenna with multi-band characteristics is presented and analyzed in this article. A patch is designed with three rectangular slots on the left and right side of the patches, an inverted L-shaped slots at the top of the patch and an ohm symbol are embedded at the center of the patch. This design produced multi-band characteristics at the frequencies of 2.2 GHz, 4.1 GHz, 5.5 GHz, 5.9 GHz and 9.1 GHz. The measured impedance bandwidth (IBW) of the structure is 2.21–2.25, 4.08–4.13, 5.47–5.60, 5.94–6.04 and 8.93–9.25 GHZ are the practical applications of ITS band, UWB, WiMAX and WLAN band signals. The proposed structure with the dimensions of 1.16 λ0 × 0.54 λ0 (85 × 40 mm2) is fabricated and tested. The separation between the two patches is maintained 0.0683 λ0 to reduce mutual coupling. The five working frequency bands of the proposed structure have an efficiency of 85.81%, 84.08%, 83.9%, 84.00% & 72.31% and gain of 3.17 dBi, 3.37 dBi, 3.69 dBi, 3.70 dBi & 3.53 dBi. The multi-band antenna provides flat-antenna gains and omnidirectional radiation patterns over five operating bands.