A Simplified Method for Reducing Mutual Coupling Effects in Low Frequency Radio Telescope Phased Arrays

Abstract

This paper presents a new approach to reduce mutual coupling effects in large phased array antennas currently under development for use in low frequency radio astronomy. A receive mode definition of coupling between two antennas is shown to serve as a good indicator of the severity of mutual coupling interactions in a phased array. Thus, an efficient way to reduce mutual coupling in the array is to design antenna elements for low receive coupling. It is demonstrated that wire inverted-V dipole antennas can be designed with significantly reduced receive coupling over a wide range of frequencies and wave directions by proper selection of the antenna element geometry and feed impedance. Corresponding improvements in the performance of a large aperiodic phased array are achieved by using the reduced coupling wire inverted-V dipole design. Both antenna coupling and phased array analyses are performed using numerical simulation. Full-scale, in situ receive coupling measurements are performed to validate the simulation results.