Defining optimum frequency range for heart failure detection system considering thickness variations in human body tissues

One of the most apparent symptoms of heart failure that can be used for its primary detection is the accumulation of fluids in lungs (pulmonary edema). However, the competency of the non-invasive microwave detection system on varying tissues thickness (mainly fat and muscle) between the skin and lungs is one of the major challenges in the design of a successful microwave detection system. The penetration of microwave signals in human body tissue depends on the utilized frequency as well as the properties and thickness of the tissues. Hence, this study investigates optimum frequencies that can be used in monitoring the accumulation of fluids in the lungs for different thicknesses of tissues layers in the torso area. The investigation uses an equivalent circuit model of the tissues in the torso area with properties that are emulated using the fourth-order Cole-Cole model. To achieve reasonable resolution, the current study focuses on the frequency band from 0.5 GHz to 1.5 GHz. A conclusion is made from all the utilized combinations in the study that the optimum band for the investigated cases extends from 0.5 GHz to 0.9 GHz.