Spiral RF Coil Analytical Modeling for Ultra-Low Field MRI Applications
Authors: Sergio Enrique Solís Nájera
Type: Short Note
Issue: Volume 1, Issue 1
Publication date: 2026-11-04
Received: 2026-10-15
Accepted: 2026-11-02
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Abstract
This study presents the analytical derivation and mathematical modeling of the quasi-static magnetic field produced by a spiral radiofrequency (RF) coil, designed for an ultra-low field magnetic resonance imaging (MRI) system operating at a Larmor frequency of 11.71 MHz. The model is constructed using the Biot-Savart law, approximating the RF coil as the superposition of eight concentric rectangular loops based on the physical dimensions of a fabricated prototype. A closed-form expression for the on-axis magnetic field is derived and numerically evaluated.