This study describes the development of a low-profile, omnidirectional, CPW-fed Ultra-Wide Band (UWB) MIMO antenna. The antenna is designed on a flexible FR4 substrate with thickness 0.07 mm, making it suitable for wearable applications. The fractional bandwidth obtained is more than 100% (3.1-9.3 GHz) which spans the wireless communication bands such as ISM (5.15-5.35 GHz), ISM (5.725-5.825 GHz), Wi-Fi (5 GHz), Wi-Max (3.4-3.6 GHz), Sub-6 GHz 5G (3.3-4.2 GHz), and WLAN (5.15-5.825 GHz). The antenna also provides safe SAR value, low envelope correlation coefficient, good antenna gain, acceptable radiation efficiency, optimum Total Active Reflection Coefficient (TARC) value, low Channel Capacity Loss (CCL), good gain, and acceptable radiation efficiency across the frequency ranges. Simulated and measured performances of the antenna in the entire band are presented.

This paper describes the concept and implementation of a compact dual-band microstrip slot antenna and its four-unit multiple-input-multiple-output (MIMO) implementation for sub-6 GHz utilizations. The proposed structure comprises a 50 ohm microstrip monopole on the top side with a defective ground structure (DGS) having semicircular and rectangular slots. This quad-element MIMO antenna has a size of 60 × 60 × 1.6 mm 3 . The proposed antenna provides wide impedance bandwidths of 23.7% (2.42 GHz to 3.07 GHz) for the first band and 42.2% (4.14 GHz to 6.37 GHz) for the second band with a mutual coupling value less than −34 dB for the two bands. The antenna also provides a low envelope correlation coefficient, good antenna gain, and acceptable radiation efficiency across the frequency ranges.