title: Decoupling and matching network for monopole antenna arrays in ultrahigh field MRI.
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.
authors.affiliation: 1 Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China ; 2 Beijing Engineering Research Center of Radiographic Techniques and Equipment, Beijing 100049, China ; 3 Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA ; 4 UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, California, USA.
authors.forename: Xinqiang
authors.initials: X
authors.lastname: Yan
authors.affiliation: 1 Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China ; 2 Beijing Engineering Research Center of Radiographic Techniques and Equipment, Beijing 100049, China ; 3 Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA ; 4 UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, California, USA.
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Zhang
keywords: Decouple; MRI; impedance matching; monopole; radio-frequency (RF) array