16-channel sleeve antenna array based on passive decoupling method at 14 T

Youheng Sun; Miutian Wang; Jianjun Du; Wentao Wang; Gang Yang; Weimin Wang; Qiushi Ren

doi:10.1016/j.jmr.2024.107796

16-channel sleeve antenna array based on passive decoupling method at 14 T

J Magn Reson. 2024 Nov 16:369:107796. doi: 10.1016/j.jmr.2024.107796. Online ahead of print.

Authors

Youheng Sun¹, Miutian Wang², Jianjun Du³, Wentao Wang⁴, Gang Yang⁵, Weimin Wang⁶, Qiushi Ren⁷

Affiliations

¹ Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, 100871, China. Electronic address: 2101112049@stu.pku.edu.cn.
² School of Electronics, Peking University, Beijing, 100871, China. Electronic address: wmt@pku.edu.cn.
³ Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, 518055, China. Electronic address: 13923815086@139.com.
⁴ Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, 518055, China. Electronic address: wangwentao@wandong.com.cn.
⁵ Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, 518055, China. Electronic address: yanggang@pku.edu.cn.
⁶ School of Electronics, Peking University, Beijing, 100871, China; Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, 518055, China; Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shenzhen, 518132, China. Electronic address: wmw@pku.edu.cn.
⁷ Department of Biomedical Engineering, College of Future Technology, Peking University, Beijing, 100871, China; Institute of Biomedical Engineering, Peking University Shenzhen Graduate School, Shenzhen, 518055, China; National Biomedical Imaging Center, Peking University, Beijing, 100871, China. Electronic address: qren@pku.edu.cn.

PMID: 39577232
DOI: 10.1016/j.jmr.2024.107796

Abstract

At ultra-high fields, especially at 14 T, head coil arrays face significant challenges with coupling between elements. Although passive decoupling methods can reduce this coupling, the decoupling elements can cause destructive interference to the RF field of the head array, thus reducing the B₁⁺ efficiency. The B₁⁺ loss due to this effect can be even higher than that due to inter-element coupling. In this study, we develop a novel passive decoupling method to improve the performance of head coil arrays at 14 T. Specifically, passive dipole antennas were utilized to decouple the 16-channel sleeve antenna array, with their positioning optimized to minimize destructive interference with the array's RF field by increasing their distance from the active antennas. We used electromagnetic simulations to optimize the position of the passive dipoles to obtain the best performance of the array. In addition, we introduced a 16-channel dipole antenna array to compare the array performance when evaluating the sleeve antenna array performance using a human body model. We also constructed the optimized sleeve antenna array and measured its S-parameters to verify the effectiveness of the decoupling strategy. Our results show that the improved passive decoupling method can well reduce the destructive interference of the decoupling elements to the RF field. The sleeve antenna array developed under this method exhibits higher B₁⁺ efficiency and better transmission performance.

Keywords: Passive decoupling; RF coil design; Sleeve antenna; UHF MRI.