CP-Stethoscope: Phantom model experiments

A phantom cross section of a human thorax was developed to evaluate the sensitivity of the Cardiopulmonary Stethoscope (CP-Stethoscope) system to detect changes in lung water content. Phantom heart and muscle tissues were also developed with dielectric properties similar to human tissue and sponges were used to model lung tissues. A structure was also built to evenly distribute water over the sponges. A 2port to 8port RF switch was developed to switch the sensors between transmitter and receiver configurations and examine sensitivity of measurement to sensors locations. Changes in the phase of the transmitted signal were correlated to the variation in the amount of the water inserted into the sponges. This experiment was used to examine the sensitivity of the CP-Stethoscope system and ability to detect water gradient in the lung. Results show that significant changes in the phase of the transmission coefficient are detectable as water migrates from the top surface to the bottom of the phantom model.