MIMO antenna system of two closely-positioned PIFAs with high isolation

A two-PIFA antenna system for diversity/MIMO applications is designed with a narrow inter-PIFA spacing of only 3 mm (less than 0.024 wavelength). The proposed antenna system can cover the WLAN band (2.4–2.48 GHz) with an isolation of better than −20 dB and a maximum isolation of −37.1 dB at the central frequency. The mechanism is explained. The measured peak efficiency and gain, and the calculated envelope correlation coefficient are 75.02%, 3.48 dBi and 0.11, respectively.