Design of an applied method with graphite structure for suppression of surface electromagnetic waves between array antennas

Abstract

In this study, a method of combining graphite structure and electromagnetic bandgap to reduce the mutual coupling of electromagnetic waves in array antennas is proposed. This structure is designed according to the special physical properties of graphite for the emission of electromagnetic waves, transmission theory, as well as the inductance and capacitive properties of the electromagnetic bandgap structure to dissipate surface currents. The proposed multi-input and multi-output (MIMO) antenna was designed and measured with two radiating elements on a substrate. The results show that the effects of mutual coupling between radiating elements are reduced by 30 dB at the operating frequency of 3.34 GHz. By placing this structure, all antenna components, including gain, patterns, and radiation efficiency, are improved. Calculations showed that antenna components: gain and antenna radiation efficiency increased by 1.2 dB and nearly 24%, respectively. To confirm the good performance of the graphite structure, all components of the MIMO antenna, including the envelope correlation coefficient, diversity gain, mean effective gain, channel capacity loss, and total active reflection coefficient, were investigated. The results showed the desired values, which indicate the very good performance of the graphite structure on all the basic characteristics of the antenna.