Dual band MIMO antenna using ENG zeroth order resonator for 4G system

We propose a two-element diversity-antenna array using epsilon negative zeroth order resonator (ENG-ZOR) at the long-term evolution (LTE) and Wibro (WiMax in Korea) bands for the multiple-input multiple-output (MIMO) application. Each element is designed by utilizing an ENG ZOR unit cell with size of 10 mm times 6 mm times 6 mm. The lower resonant frequency is fixed by the zeroth order resonance of the ENG ZOR and the higher is selected by the radiator utilizing the first order resonance of the ENG ZOR. An isolator is added between the two elements in order to enhance the isolation characteristic at higher band of the designed MIMO antenna. The MIMO antenna is fabricated on the top side of the ground plane with size of 48 mm times 108 mm times 0.4 mm. The fabricated antenna has the isolation of about 20 dB at the lower band and higher than 13 dB at the higher band.