Design requirements of microwave sensor for pneumothorax diagnosis

We investigate the design of a low-power, non-invasive device for detection of air cavities in the space between chest and lung (i.e. pneumothorax). To this end, we study the operational frequency band and sensitivity capabilities of such device. Simplified scenarios of parameterized layered biological models in the exposure of electromagnetic plane wave and coupled radiating antennas are assessed, via an analytical solution and Finite Difference Time Domain (FDTD) method. The frequency band under study is 1-10 GHz. Differential comparative calculations of reflection coefficient and reflected electric field indicate the frequency band and resolution of the sensor. Results reveal that the existence of air alters considerably the reflection coefficient in the frequency band of 1-3 GHz. The resolution of the sensor is predicted to reach 5 mm of air layer thickness.