A 4-element dual wideband circular Yagi MIMO antenna system with loop excitation

A 4-element dual-band Circular Yagi based multiple-input-multiple-output (MIMO) antenna system with loop excitation is presented. It has a very wide-bandwidth of 1 GHz in both bands. The lower band covers from 1.45-2.55 GHz while the upper band covers from 3.707-4.71 GHz. This antenna is highly directional with front-to-back ratio (FBR) of 13.8 dB, gain of 6.6 dB and directivity of 7 dB. The proposed antenna shows good MIMO performance in terms of isolation and correlation. It has a minimum isolation of 23 dB across both bands. Due to its geometry configuration, the radiation patterns are orthogonal to each other and hence it has very low correlation coefficient values not exceeding than 0.1338. The size of the single antenna is 78 × 117.5 mm² while overall size is 263 × 263 mm².