Decoupling and Matching Strategies for Compact Antenna Arrays

Abstract

Since the MIMO technology presents antenna arrays that can be formatted with tens to hundreds antenna elements, several effects arise due to this array structure, such as mutual coupling and impedance matching among antenna elements in the array. The treatment of these issues seeks to solve problems such as the performance degradation of communication systems. In this context, this paper proposes and evaluates three strategies of joint decoupling and impedance matching networks (DMN) for antenna arrays. The first method, called DMN with Lumped Elements (DMN-LE), performs the decoupling and impedance matching steps with capacitors and inductors. The second method, called DMN with Ring Hybrid (DMN-RH), utilizes a microstrip line in a ring format. The third method, called Networkless Decoupling and Matching (NDM), brings a concept of decoupling without the presence of a network itself, which 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. The figure-of-merit for this comparison is the antenna bandwidth, for which both matching and decoupling are measured against S-parameters below a given threshold. We conclude that the third method is a promising new alternative approach.

Low Frequency Multi-Robot Networking

“…Multiport impedance matching networks are also referred to as external coupling networks (ECNs) [135], decoupling and matching networks (DMNs) [134], [136], and other descriptors [133], [137]. The term ECN is used in this section for simplicity and we consider ECNs that are linear, passive, lossless, and reciprocal.…”

“…The term ECN is used in this section for simplicity and we consider ECNs that are linear, passive, lossless, and reciprocal. ECNs are implemented with lumped circuit components (inductors or capacitors), distributed reactive components (transmission lines), parasitic antennas, or a combination of these components [133], [136]. Lumped elements may provide more compact ECNs at low frequency than transmission lines.…”

“…Parasitic antennas are indicated as optional elements in Figure 10, and they have been shown to improve compact array systems by increasing the effective radiation resistance of the active antennas [139], increasing the system bandwidth [139], [140], or simplifying the matching network by decoupling the active antennas [136], [140], [141]. Therefore the parasitic antennas, if included, may be considered as part of the impedance matching subsystem.…”