MIMO/Diversity Antenna with Neutralization Line for WLAN Applications

A four-port multi-input-multi-output (MIMO) antenna is designed for the WLAN access point applications. The prospective antenna consists of four double-layered printed dipole antennas (DLPDAs), where two elements are designed to resonate at a frequency of 2.45 GHz and the resonant frequency of the other two elements is 5.8 GHz. The resonant bandwidths of the DLPDAs are 24.7% (2.09-2.68 GHz) and 28.9% (4.73-6.33 GHz) at 2.45 GHz and 5.8 GHz, respectively. The proposed MIMO antenna is printed on the FR-4 substrate of size 45 mm x 60 mm x 1.6 mm. A decoupling network is introduced in the center of the proposed antenna to achieve high isolation between resonating elements. The decoupling arrangement is a combination of four metal strips and a circular loop that acts as a neutralization line. It opposes the direct coupling current and provides isolation of around 20.55 dB at 2.45 GHz and 33.08 dB at 5.8 GHz.