Compact 8-Channel Phased Array Stepped Impedance RF Coil for 9.4 Tesla Spinal Cord MRI

This article proposes a novel 8-channel Stepped Impedance Structure (SIS) RF coil for spinal cord imaging applications at 9.4 Tesla. The presented RF coil comprises eight stepped impedance structured elements arranged in a phased array configuration, each channel spaced 6mm apart on a 17 x 50 cm substrate. The SIS RF coil incorporates three distinct impedance levels and a capacitor-capacitor (CC) matching network to achieve resonance at 400 MHz. To evaluate the effectiveness of the designed RF coil, a comparative analysis of various spacing configurations specifically with 5mm and 10mm gaps between the channels of RF coil. The phased array RF coil functionality is assessed through S-parameter analysis, demonstrating a return loss of 36 dB at the operating frequency. The study confirms that the proposed RF coil achieves the desired frequency and performance characteristic making it an effective candidate for integration into the spinal cord MRI system.