Evaluation of an Analog Wide-Bandwidth Gain and Phase Detector for a Compact Electrical Impedance Tomography Data Acquisition System

Abstract Electrical impedance tomography (EIT) is a technique used in industrial, food, and medical applications. It operates by injecting a constant current through electrodes and measuring peripheral voltages in an array of 16 to 256 electrodes. This work presents an EIT system based on the AD8302, a phase and magnitude detector operating from DC to 2.7 GHz. It complies with IEC60601 standards, enabling its use in clinical environments such as breast cancer detection and muscle tissue analysis. In order to comply with the mains electrical safety isolation guidelines, the data acquisition system is powered by means of two embedded switched converters: AC/DC converter (4KV isolation) and DC/DC converter (1.5 kV) Isolation. Excitation is generated using the AD9833 and an improved Howland current source (100 µA to 1 mA). A microcontroller, Atmega 2560, controls the measurement process using 16 electrodes selected via ADG1406 multiplexers. Image reconstruction is performed with the Linear Backprojection algorithm in Visual Studio. Tests in an acrylic tank with copper, PVC, carrot, and potato inclusions demonstrated accuracy in locating biological and non-biological materials. The system stands out for its modular design and high safety, making it a promising tool for medical and industrial applications.