A Multicircle Planar Electrical Impedance Tomography Sensor for 3-D Miniature Imaging

In this article, a multicircle planar electrical impedance tomography (EIT) sensor is proposed for three-dimensional (3-D) miniature imaging. There are two problems in 3-D miniature EIT imaging: 1) the spatial resolution is low since the number of electrodes is limited and 2) contact impedance influences image reconstruction quality severely. The proposed EIT sensor made by a printed circuit board (PCB) adopts a multicircle structure and tackles the two problems. Driven electrodes are distributed on the outermost two circles, while measurement electrodes are distributed on the innermost circle. Contact impedance is reduced since the area of driven electrodes could be larger than traditional ones by using the multicircle structure, and it is also owning to gold that is deposited on the surface of the electrodes. Moreover, a new driven-measurement pattern of the EIT sensor is proposed to improve the spatial resolution as well as image reconstruction quality. The proposed EIT sensor is verified by both simulation and experiment. The average image correlation coefficient (ICC) is as high as 0.8475 in simulation. Compared with the 16-electrode EIT sensor, ICC is improved by 39.16%. In the experiment, the average ICC of four standard objects is 0.8389. The proposed 3-D EIT sensor is good at miniature imaging.