Enhancing Farfield Isolation between Nearby Base Station Array Antennas by a Resistive Film Wall

Abstract

With the development of 5th Generation Mobile Communication Technology, large array antennas have been widely used in base stations, while the farfield isolation of array antennas is an urgent problem to improve. Related research in the past has focused on the isolation between the array elements. Some isolation structures, like metal wall with different shape unit are widely used to reduce the coupling of the array elements. However, the farfield isolation between different arrays and the effects of the sidelobe on isolation get bare attention and still need more research. In this work, a wall structure around array antenna based on resistive film is proposed to improve the farfield isolation without affecting the radiation characteristics of the main lobe. We investigate the effects of the resistive film wall on the farfield isolation in a practical case of two dual-polarized array antennas with certain distance using commercial software CST Microwave Studio. By utilizing resistive films with different sheet resistivity, desirable farfield isolation improvement and less than 2dB insertion loss for the main lobe are validated in both simulation and measurement. The proposed resistive film wall for array antennas demonstrates a good potential application for electromagnetic compatibility in base station.