Study On System For Magnetic Induction Tomography

Magnetic induction tomography is a non-invasive and non-contact electrical imaging technique.It is mainly based on the principle of eddy current detection.The transmitting coil produces a primary electromagnetic field,then a same frequency eddy current can be induced on the object placed in the primary field due to its conductivity.The eddy current will produce a secondary magnetic field,which can be seen as a disturbance of primary field.Through measuring this disturbance using the receiving coil and imaging with algorithms,the electrical characteristics distribution of the object can be obtained.This technique is sensitive to the conductivity,permeability and dielectric constant of an object and can be functionalized.Compared with the existed technologies such as X-Ray computed tomography,magnetic resonance imaging and ultrasound imaging,magnetic induction tomography is no harm,fast,simple and lowcost features.It has broad prospect in clinical and safety monitoring applications.In this paper,with a large number of research,a new structure of transmitting coil which can replace the traditional solenoid coil is proposed based on the fundamental characteristics of the existed magnetic induction tomography system.Different transmitting coil structures are designed and improved,and the transmitting coils of this new structure are tested by using the gradient structure and single coil structure,respectively.The experimental results show that the novel structure has good characteristics such as good frequency selection,low power and large magnetic field,which is promising for the future magnetic induction tomography system.In addition,foundation and explanation of impedance matching phenomenon in receiving unit is proposed,through the system to build and test.It is easy to know that using a simple adjustment of impedance can easily amplified the detected signal without and affect of the quality of the detected signal.At the same time,a coaxial reverse transmission coil structure was fabricated and tested,which verified the improvement of the magnetic field distribution and made the primary magnetic field more uniform and easier to test.