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

Abstract

Today's healthcare system relies on magnetic resonance imaging (MRI) for early diagnosis and treatment planning. For open MRI systems to achieve resolutions of about a hundred microns, a high voltage is required, as well as a specialized power supply. Negative–positive–zero (NP0) ceramic is selected for the fabrication of adjustable capacitors. Specifically, it stands for which is a classification based on the temperature coefficient of capacitance (TCC) of the ceramic material used in the capacitor. NP0 capacitors have a TCC of 0 ±30 ppm/°C, which means that their capacitance value does not change significantly with temperature and frequency. They are known for their stability and low losses, making them ideal for applications that require high accuracy and reliability, such as timing circuits for radio frequency (RF) applications. Here, MgTiO3–CaTiO3 ceramic is used to make an adjustable capacitor with desired properties for MRI systems. To enhance the dielectric properties of MgTiO3 ceramics, CaTiO3 was added in varying concentrations. After pressing and sintering, the resulting samples were tested using a vector network analyzer in the frequency range of 10–130 MHz. The adjustable capacitor fabricated using high co‐fired NP0 ceramic may have been used for MRI applications such as tuning circuits and matching networks, where precise capacitance values and low loss are critical. MRI systems with resonance frequencies of 128 MHz require trimmers with ceramic cores (VBreakdown = 3 kV @ 128 MHz, Cmin = 3 pF, CMax = 30 pF, and Cvariation step = 1.5 pF).

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“…In this section, we delve into the assessment of capacitance behavior through HFSS simulations and the identification of resonance frequencies [8], [9]. Figure 9 presents a comprehensive 3D model of the prototype featuring a margin, offering valuable insights into the simulated conditions.…”

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“…In this section, we delve into the assessment of capacitance behavior through HFSS simulations and the identi cation of resonance frequencies [8], [9]. Figure 9 presents a comprehensive 3D model of the prototype featuring a margin, offering valuable insights into the simulated conditions.…”