An ultra-compact two-port UWB-MIMO antenna with dual band-notched characteristics

In this paper, an ultra-compact two-port MIMO antenna working in the frequency range of 3.1–10.6 GHz with dual band-notched characteristics is presented. The MIMO antenna consists of two identical octagonal-shaped radiating elements placed adjacent to each other with a connected ground plane. The overall size of the proposed two-port UWB-MIMO antenna is 19 × 30 × 0.8 mm 3 . In the ground plane of antenna elements , a T-shaped stub is introduced to create band-notch at 5.5 GHz. Also, an open-ended half-guided-wavelength resonator slot is introduced along the upper edge of the octagonal radiator to obtain a broader notched-band (4.37–5.95 GHz). The second band-notch is created around 7 GHz (6.52–7.45 GHz) by etching another open-ended slot from the radiating patch . The two-notch bands reject interference due to HiperLAN, WiMAX, INSAT/Super-extended C-band, downlink of X-band satellite communication and RFID service bands. A pair of L-shaped slits are introduced in the feed line to improve impedance matching , for the frequency band available between the two notches. The proposed design is fabricated on an FR-4 substrate and minimum isolation greater than 18 dB (a major portion >22 dB) and envelope correlation coefficient (ECC) less than 0.13 are obtained. The antenna gain varies in the range of 1.2–2.91 dBi with a variation of 1.71 dBi only. A radiation efficiency, greater than 70% is achieved throughout the operating frequency band.