A Miniature Two‐/Four‐Port UWB Antenna With MIMO Characterization Having Three Stopbands and Pattern Diversity Useful for 5G/6G/WiFi‐6E IoT Mobile Devices

ABSTRACT This study introduces an innovative tree‐shaped two‐ and four‐port multiple‐input and multiple‐output (MIMO) antenna modeled to be used in unlicensed ultrawideband (UWB) systems suitable for 5G midband (4.8–4.9 GHz), extended WiFi‐6‐GHz band, and 7‐GHz 6G Spectrum (7.025–7.125 GHz) mitigating interference with other useful wireless bands such as WiFi‐5 frequency band (5.15–5.85 GHz), IEEE 802.16 band (3.3–3.7 GHz), and Satellite C‐band extension (6.7–7.1 GHz). Wide bandwidth, low profile, small size, low mutual coupling, low cost, stable radiation pattern, good gain, efficient diversity parameters, minimum channel capacity loss, and mitigating interference with highly engaged bands are among the few design challenges faced by such band‐notched UWB MIMO antennas. The low‐profile, efficiently downsized two‐port tapered transformer‐based microstrip line‐fed antenna makes use of an economical FR4 substrate that measures 0.33 λ 0 × 0.43 λ 0 . The measured −10dB impedance bandwidth covers the frequency spectrum from 2.8 to 11 GHz, with a maximum isolation of 17.5 dB between both ports. A vertical rectangular notch on the ground plane and a grounded conducting stub are used to improve isolation. To prevent interference with WiMAX, WLAN, and weather satellite applications, it has three‐stop bands with the aid of rectangular slot stubs on the ground, a C‐slot on the feedline, and a J‐slit on the patch. Surface electrical current analysis confirms the nonfunctionality of the antenna at these notch bands. Moreover, the investigated radiation behavior of the antenna confirms that the power level at notch frequencies is significantly lower than the −3dB value. In pursuit of better radiation performance, a four‐port MIMO antenna is also suggested and evaluated. The four‐port proposed MIMO antenna exhibits excellent pattern diversity and improved isolation in the band from 2.8 to 10.6 GHz. Time domain analysis and MIMO performance metrics for the suggested two‐ and four‐port antenna are also studied. Results show good modeled and experimental agreement for both two‐ and four‐port antennas, suggesting their potential use for 5G/6G/WiFi‐6E IoT Mobile Devices.