A compact printed 2 × 2 ultrawideband (UWB) multiple input multiple output (MIMO) antenna with a single circular patch as a common radiator for both the antenna elements is presented in this paper. A single circular patch is excited by two tapered CPW feeds for dual polarization. To improve the isolation between two ports, a rectangular slot of dimension L1 × W1 is created in the radiator. The UWB MIMO antenna has impedance bandwidth of 3–12 GHz with a isolation better than 17 dB between the two ports. The envelope correlation coefficient and the capacity loss are evaluated to ensure the good diversity performance of UWB MIMO antenna. The antenna has a compact size of 45 × 45 mm2 and is fabricated on low cost FR4 substrate and measured using Agilent VNA. The simulated and measured results show that the proposed UWB antenna is good candidate for UWB MIMO applications.

In this report, a compact antenna system with dual-band-notched characteristics is proposed for ultra-wideband (UWB) multiple-input multiple-output (MIMO) applications. Two antenna elements are placed side by side and fed with matched microstrip lines on a substrate with an area of 35 × 30 mm2. Notched characteristics at WiMAX (3.4–3.6 GHz) and WLAN (5.725–5.825 GHz) have been achieved using complementary split ring resonator (SRR) slots etched in both the antenna elements. Electromagnetic isolation between the two elements close to each other is achieved using a ground T-stub and slots etched in the ground plane. Antenna system has been tested and measured results are close to the desired ones. Measured isolation >20 dB is obtained in most of the UWB bands. The proposed antenna system meets the requirements well for MIMO applications.

A novel compact multiple-input–multiple-output (MIMO) antenna system operating from 5 to 7.3 GHz is proposed for wireless applications. It comprises of two similar antennas with microstrip feeding and radiating patches developed on a reduced ground plane. The developed antenna system resonates at a dual-band of 5.4 and 6.8 GHz frequencies, giving an impedance bandwidth of 38% (based on S11 < −10 dB). The unique structure of the proposed MIMO system gives a reduced mutual coupling of −27 dB at 5.4 GHz resonant frequency and −19 dB at 6.8 GHz resonant frequency and in the entire operating band the coupling is maintained well below −16 dB. The envelope correlation coefficient of the proposed MIMO system is calculated and is found to be less than 0.05 in the operating band. The measured and simulation results are found in good agreement.