High inter-element isolation and WLAN filtering mechanism: A compact MIMO antenna scheme

Abstract A multiple-input-multiple-output (MIMO) wireless local area network (WLAN) band-notched antenna with high inter-element isolation is proposed. The proposed MIMO system is composed of two monopole antennas, each composed of a slotted radiating patch and a stepped ground plane. The embedded slots and the ground plane steps are wisely located to achieve the desired wide band functionality as well as WLAN band-notched realization. The overall size of the MIMO antenna is 20 × 34 mm2 printed on 1.6 mm FR4 substrate. Moreover, to reduce the coupling between the constituent monopole antennas and enhance the isolation, a parasitic element is embedded between the antennas on the substrate backside. By wise tuning of the position and dimensions of the parasitic element, high isolation is achieved which is necessary for MIMO communication systems. Both simulation and measured results confirm a 10-dB impedance bandwidth of 2.6–11.2 GHz excluding the rejected band for |S11| ≤ −10 dB, and |S21| ≤ −20 dB. Wide bandwidth, small size, and band-notched feature are some of the merits of the proposed MIMO antenna. Detailed analysis on the antenna performance are released in detail throughout the paper.