Compact-sized, Dual-element MIMO antenna together with Partial and Defected Ground Structure for 4G/5G UWB applications

The article reports the designing and experimental analysis of a printed 2×2 MIMO array with fork-shaped antenna elements for high data rate UWB (3.5-12.17GHz) 4G/5G wireless communications. The proposed antenna has overall dimensions of 28×52.2×1.64mm
³
and is designed on a commercially available 1. 57mmFR4 epoxy substrate. The proposed array has two microstrip-fed antenna elements, each with a fork-shaped geometry formed by using two similar slotted rectangular patches attached to two L–shaped stubs to excite multiple resonances. The antenna ground structure is reduced and is made defected with triangular notches, and I-shaped slots to excite the ultra-wideband of operation with a fractional bandwidth (FBW of 110.7% at 7. 835GHz). The isolation between array elements is improved by using a rectangular decoupler that is elongated from the center of the reduced ground toward the top of the FR4 substrate ($\mathrm{S}_{12}\leq-$16.41dB). The array’s applicability in any of the diversity schemes is supported by ECC ($\leq$0.009), DG ($\geq$9.954), MEG ($\leq-$ 3.335dB), and TARC ($\leq$7.4dB). A measured radiation and diversity performance (using a VNA) in terms of S
11
with 9S.67% FBW (4.41-13GHz), S
22
with 97.3% FBW (4.49-13GHz), and S
12
/$\mathrm{S}_{21}\leq$-15.41dB respectively validates the simulated results. The simulated and tested responses exhibit an acceptable resemblance which allows the successful usage of the designed array for effective communications in UWB systems.