Project Summary/Abstract This proposal is to develop a miniature balun to meet the emerging meet in flexible RF coils in MRI. Flexible coils improve patient comfort and can be formed into desired shapes to match the human anatomy of interest. Therefore, compared to conventional rigid coils, they exhibit improved filling factor and signal-to-noise ratio, especially when imaging curved anatomies such as cervical spinal cord, pelvis, and hands. Although the challenges in building flexible coils have been solved with the numerous methods mentioned above, in practice, it is still an open question to make fully flexible coils since the balun or cable trap circuits associated with coils are still rigid and bulky. The first goal of this project is to theoretically analyze, build and test a miniature LC balun with a novel topology, namely LCCC balun. The second goal of this project is to integrate the LCCC balun with flexible receive-only coils and transmit/receive coils at 3T and 7T. The theoretical analysis, script for component value calculation, circuit simulation models, and PCB designs, will be distributed for open access. This miniature LCCC balun can be easily transferred to other RF coil designs, with benefits for the entire community.