Reduction of mutual coupling in active antenna arrays by optimized interfacing between antennas and amplifiers

This paper discusses the reduction of mutual coupling in active antenna arrays. A broadband lumped-element circuit model is developed for an array of aperture-coupled patch antennas. This allows simulating and optimizing the mutual coupling in a standard circuit simulator. Experimental results at 5.5 GHz demonstrate that the mutual coupling can be significantly reduced by adjusting the electrical distance between the amplifier and the antenna phase center. This simple technique proved to be useful especially for active antenna arrays based on standard MMIC amplifiers.