Abstract
We evaluated analytically and experimentally the performance of a planar gradiometer as a sensing element in a system for magnetic induction tomography. A system using an excitation coil and a planar gradiometer was compared against a system with two coils. We constructed one excitation coil, two different sensing elements and a high-resolution phase detector. The first sensor was a PCB square spiral coil with seven turns. The second sensor was a PCB planar gradiometer with two opposite square spirals of seven turns, with a distance between centres of 8 cm. Theoretical sensitivity maps were derived from basic equations and compared with experimental data obtained at 150 kHz. The experimental sensitivity maps were obtained measuring the perturbation produced by a brass sphere of 12 mm in empty space. The advantage of using a gradiometer is that it can be adjusted to give a minimum signal for homogeneous objects, while increasing the sensitivity to local perturbations of the conductivity. Results show that a system using a planar gradiometer as detector has less demanding requirements for the electronic system than a system using simple coils.
Original language | English |
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Pages (from-to) | 121-130 |
Number of pages | 10 |
Journal | Physiological Measurement |
Volume | 22 |
Issue number | 1 |
DOIs | |
Publication status | Published - 14 Mar 2001 |
Keywords
- Bioimpedance
- Eddy currents
- Electromagnetic tomography
- Magnetic induction
- Planar gradiometer
ASJC Scopus subject areas
- Biophysics
- Physiology
- Biomedical Engineering
- Physiology (medical)
Fields of Expertise
- Human- & Biotechnology