Sensitivity study for improved magnetic induction tomography (MIT) coil system

The improved magnetic induction tomography (MIT) coil system which consists of the two-arm Archimedean spiral coil (TAASC) as excitation coil and the solenoid as receiver coil has much better performance in coil system sensitivity than the conventional MIT coil system which uses the solenoids as excitation coil and receiver coil. In this paper the theoretical sensitivity property for improved MIT coil system are studied fully. The magnetic fields produced by TAASC and solenoid are derived approximately based on the Biot-Savart law. The relations between the coil system sensitivity and the parameters (amplitude of excitation current, maximum outer radius and number of turns of TAASC, and number of turns and length of solenoid) of coil system are calculated. The results show that the sensitivity for improved MIT coil system is proportional to the number of turns of solenoid and electric current of TAASC, and can be improved with the increase of maximum outer radius of TAASC and radius of solenoid. The sensitivity is decreased as the length of solenoid increasing, and not significantly associated with the number of turns of TAASC.