Slot and SRR-Loaded Quad-Port, Hen-Shaped Fractal UWB-MIMO Antenna with Quad Band-Reject Ability for Handheld 4G/5G Wireless Devices

In this paper, a four-element hen-shaped fractal MIMO antenna is prototyped, simulated, and experimentally affirmed for ultra-wideband characteristics with the eradication of four interfering narrowband applications. The array is configured on a 1.57-mm-thick FR4 epoxy substrate which primarily consists of four tapered and offset-fed circular radiators (each slotted with 4th order hen-shaped fractal) and defected ground surface, targeted to realize 141% fractional bandwidth (3.1–18 GHz) with a significant degree of inter-port isolation response. The proposed fractal configuration provides a 52.6% decrease in patch area in comparison with the basic circular geometry. Additionally, a modified Z-shaped slot and rectangular split ring resonator (SRR) is clipped off from each radiating element to filter out the intrusion associated with the downlink C-band (3.76–4.58 GHz) and INSAT (transmission) band (6.647–7.118 GHz), respectively. The array’s partial ground structure is loaded with four rectangular SRR pairs to get rid of the undesired WLAN (5.15–5.77 GHz) application. A U-shaped slot is truncated from each feedline of the proposed array to realize a notch at 8.18 GHz (ITU-8). Several diversity performance metrics are studied and they subsist within their allowable standard values. The experimental responses of the fabricated array design correspond well with the simulation outcomes, thereby affirming the array’s real-time functioning in ultrawideband communication systems.