Design of planar inverted F-antenna over uniplanar EBG structure for laptop MIMO applications

A simple multiband of multiple-input-multiple-output (MIMO) antenna with low mutual coupling is proposed for laptop application. The proposed antenna consists of two planar inverted F-antenna (PIFA) elements. Each element consists of two trapezoidal shaped slots within the radiating plate and uniplanar electromagnetic band gap within the ground plane. EBG ground plane is used for obtaining lower cut off frequency, increase the gain, and larger bandwidth. The proposed uniplanar shape is easy to fabricate without the use of vias or other kinds of vertical connections. The proposed antenna is designed to cover two narrow bands namely GSM 1.8 GHz, upper WLAN 5.2 GHz and a wideband from 2.4 GHz to 4 GHz. Moreover, mutual coupling reduction by using EBG is studied, where two integrated antenna elements can operate simultaneously. Results show that the MIMO antenna has mutual coupling of less than -35 dB at 5.2 GHz, and less than -15 dB through other frequencies. The average envelope correlation coefficient is less than 0.3 over the operating frequencies. All these features enable the proposed antenna to be a good candidate for MIMO laptop applications.