Decoupling and matching network for monopole antenna arrays in ultrahigh field MRI

Xinqiang Yan, Xiaoliang Zhang

Abstract

Background: Radiative coil arrays, e.g., dipole or monopole arrays, are increasingly used in MR signal excitation and reception for ultrahigh field MRI. Technically, it is challenging to suppress the electromagnetic (EM) coupling of radiative array elements due to their unique structures.
Methods: In this study, we proposed a combined decoupling and matching network (DMN) for monopole arrays for MRI applications. Compared with separate decoupling network and matching network, the combined network proposed here needs less components and rather suitable for decoupling radiative arrays in MRI.
Results: Our study shows that the transmission coefficient between two coupled monopoles can be reduced from −5 dB to −24.8 dB by using the combined DMN. It is also clearly demonstrated in this study that this decoupling method is a port decoupling method rather than an element decoupling method.
Conclusions: With the proposed DMN, the monopole coil provides locally strong and spatially diverse B1 fields, which is essential to the improvement of MR sensitivity and parallel imaging performance.