Microwave based Non-Invasive Localized Anomaly Detection in Wood as a Biological Tissue Phantom
Annesha Mazumder, Anwesha Khasnobish, Tapas Chakravarty, M. Jaleel Akhtar · 2023
Localized anomalies in biological tissues, such as tumors, wounds, and edema, possess microwave properties starkly different from the healthy tissues. Microwave imaging (MWI) utilizes the changes in the electric properties of the tissues to detect anomalies in these tissues by forming an image of the test region. We present a novel, non-invasive technique to detect the localized anomalies in biological tissues using microwaves for in-vivo applications. Here, the scattering measurements of the test specimen are carried out in the microwave frequency range using a Vector Network Analyzer (VNA), and a modified calibration technique is utilized for de-embedding the calibration plane to the surface of the sample. Wood is used as a biological tissue phantom in the present situation, where a localized anomaly is introduced. The transmission characteristics of the wood sample measured using the VNA are utilized to estimate the change in attenuation and phase constant due to the introduction of an anomaly in the specimen. These changes are subsequently used to compute the dielectric constant (ϵr) and loss tangent (tan δ) of the test specimen. The results suggest that the proposed technique can efficiently differentiate between healthy tissues and tissues with anomalies, with a variation of nearly 50 % in the complex permittivity between the two.