The Enhancement of Radio Frequency Magnetic Field for a 1.5 Tesla Magnetic Resonance System Using a High Impedance Surface

This paper presents a novel design of a High Impedance Surface (HIS) to improve the magnetic field strength of a Radio Frequency (RF) coil at 63.8 MHz, suitable for 1.5T magnetic resonance imaging (MRI) systems. The HIS is miniaturized using distributed interdigital capacitors. A HIS with an electrically small unit cell (λ/94) and is positioned between a RF transmit-receive (TR) coil and an RF shield. The magnitude of the magnetic field from an RF coil when coupled to a dielectric phantom load (mimicking a biological sample) was estimated using numerical simulation (finite integral methods) and corroborated with measurements. Simulated median improvements in magnetic field inside a dielectric phantom range from approximately 18% to 32% depending on the area of the HIS.