A novel ITI-shaped isolation structure placed between two-port CPW-fed dual-band MIMO antenna for high isolation

Abstract

In this paper, a novel structure of CPW-Fed MIMO antenna is presented for dual-band applications covering 2.4/5.8 GHz ISM band, 2300 MHz LTE-4G band, HiperLAN (5–6 GHz) and IEEE C-bands. A Rectangle-Split-Ring-Resonator (RSRR) slot has been embedded in the patch antenna to create a band-notch centered around 3.74 GHz in order to isolate the high traffic of 3.5 GHz WiMAX band and convert a wideband antenna into a dual-band antenna which is mainly focused on the WLAN bands. A modified ground structure is implemented to control and achieve a higher impedance bandwidth (IBW) up to 64% in the upper band, ranging from 3.90 to 7.55 GHz while the lower band, ranges from 2.24 to 2.90 GHz with an IBW of 26%. A novel ITI-shaped isolation structure is designed and placed between the patch antennas, which are separated by a center-to-center distance of 0.35λ0, helping in achieving a minimum measured isolation of 24 dB across the dual-band. The design has been fabricated on an FR-4 substrate of dimension 72 × 56 × 0.8 mm3 with a minimum measured gain of 2.5 dBi across the operating bands.