FEM simulation‐based development of a new tunable non‐magnetic RF high voltage capacitor for the new generation of MRI

Abstract

Using Radio Frequency (RF) waves, magnetic resonance imaging (MRI) systems can make detailed images of human organs for accurate diagnostic processes and disease detection. The overhaul of certain electronic components has become necessary to keep up with the progress of MRI systems. Among the components responsible for image quality, the adjustable non-magnetic capacitors, also called trimmers, are of great importance. The purpose of this paper is to suggest a new design of a trimmer using non-magnetic materials, able to hold a high voltage ( >3 kV) and reach a resonance frequency above 100 MHz. Constructional analysis performed on existing commercial trimmers, combined with the electrical Finite Element Method, were carried out to propose a prototype matching the desired specifications. A dielectric shield surrounding the electrodes was sized to ensure voltage withstand. Moreover, the rotor and the worm-and-gear set were joined together to combat the vibrations generated by the MRI system. The present study includes the modelling step of the component by numerical simulation, the manufacturing, the electrical performance characterization, and the mechanical solution for tuning capacitance. The final prototype combines electrical performance corresponding to the required specifications in particular a high breakdown voltage (39.7 kV) and a resonance frequency (130 MHz).

Advancing MRI capacitors: Design, fabrication, and characterization

“…This section is dedicated to the intricacies of our ceramic design, a critical facet of our investigation. Amidst the realm of High‐Temperature Co‐Fired Ceramics (HTCC), our choice for the dielectric material in the prototype gravitated towards MgTiCa, as substantiated by references [6, 7], and [8]. Renowned for its NP0 High‐Fired Ceramic properties, MgTiCa offers a gamut of advantages.…”

“…As a result, these seemingly discrete components can enhance diagnostic precision in MRI, leading to improved patient outcomes and elevating medical imaging to unprecedented levels of excellence. It is our commitment to progress and the advancement of human health that drives the design, fabrication, and characterization of MRI capacitors [6].…”

Investigating the effects of uniaxial pressure on the preparation of MgTiO3–CaTiO3 ceramic capacitors for MRI systems

“…Passive components used in medical resonance imaging (MRI) applications are facing voltage breakdown issues, which have prompted the development of novel structures for adjustable capacitors due to the increasing demand for higher voltages [1]. Consequently, conventional trimmers no longer meet the performance requirements of the new generation of MRI systems [2].…”

“…The dielectric part of the trimmer, including its nature, shape, and air gap, is crucial in improving the operating voltage and avoiding electric discharge [1][2][3]. Dielectric breakdown occurs when the electrical field exceeds the dielectric strength of the material, resulting in partial ionization [4,5].…”

Advancing MRI Capacitors: Design, Fabrication, and Characterization

“…As a result, these seemingly discrete components can enhance diagnostic precision in MRI, leading to improved patient outcomes and elevating medical imaging to unprecedented levels of excellence. It is our commitment to progress and the advancement of human health that drives the design, fabrication, and characterization of MRI capacitors [4].…”