Decoupling and matching strategies for compact antenna arrays

Abstract

This paper proposes and evaluates three strategies of joint decoupling and impedance matching networks (DMN) for antenna arrays. Since MIMO technology presents antenna arrays which can be formatted with elements of the order of tens to hundreds, several effects due to this structure have emerged, such as mutual coupling and impedance matching among antenna elements in array. Therefore, the treatment of these issues seeks to solve problems such as the degradation of the performance of the communications system. The first method called DMN with Lumped Elements (DMN-LE) performs the decoupling and impedance matching steps with capacitors and inductors. The second method is called DMN with Ring Hybrid (DMN-RH). It utilizes a microstrip line in the ring form. With this approach is due achieves first the decoupling followed by impedance matching step. The third method is called Networkless Decoupling and Matching (NDM). It brings a concept of decoupling without the presence of a network itself. This enables modeling an antenna array that performs DMN operations in a simplified and compact manner. A comparison of the methods is performed both analytically and via computer simulations. We conclude that the third method is promising new alternative approach.