J-Pole Antenna Array for Magnetic Resonance Imaging at 11.74 T: Simulation and Preliminary Results

This is the authors' abstract. We don't add key points for this paper.

The J-pole antenna array, initially introduced for hybrid medical imaging systems, such as simultaneous MR-PET acquisition, has been shown to avoid compromising system performance or image quality compared with single-modality instrumentation, highlighting its potential for advanced MRI applications. In this work, we present the design, construction and validation of an 8-channel J-pole antenna array specifically developed for a unique 11.74 T human MRI system, one of the highest field strengths operational worldwide. Each antenna element was constructed using copper wire tuned to 500 MHz with a physical length of approximately 240 mm, requiring no capacitors for an exceptionally simple design. Eight elements were evenly distributed on a cylindrical tube with a diameter of 270 mm and operated in circularly polarised mode. The performance of the array was evaluated through electromagnetic simulations using both a homogeneous water phantom and a more anatomically realistic human Duke model. This was followed by experimental validation through bench measurements and MR imaging on the 11.74 T scanner. Complex field patterns were observed in the phantom at this field strength, although these effects were less pronounced in the Duke model. The optimal dimensions of the J-pole antenna array for human brain imaging, its unique end-fed configuration that minimises cable coupling, and its straightforward construction establish it as a foundation for future coil-array developments at extreme field strengths.