A Miniaturized Dual UWB Quasi-Yagi based MIMO Antenna System Using a Defected Ground Structure

In this work, a dual ultra-wideband (UWB) 2-element Quasi-Yagi based multiple-input-multiple output (MIMO) antenna system is proposed based on loop excitation. A novel defected ground structure (DGS) acting as a parasitic reflector element is used to achieve 48% reduction in size without compromising other performance metrics. The center frequency of operation is 2 GHz. The proposed dual-band MIMO antenna system has a wide measured bandwidth of 1.72 GHz from 1.9-3.62 GHz and 1.70 GHz from 4.6–6.3 GHz covering the GSM/EDGE/LTE, WLAN, Bluetooth, Wi-Fi, and WiMAX bands. The proposed MIMO antenna system occupies a size of 80×120×0.76 mm3, The maximum measured realized gain and total radiation efficiency of the MIMO antenna system are found to be more than 5 dBi and 80%, respectively, within both bands. Aside from good Yagi-Uda performance, the proposed antenna system also shows excellent MIMO performance, with minimum measured isolation of 15 dB and measured envelope correlation coefficient (ECC) value of 0.0341 in both bands.