Generic Wideband Phantom Design Methodology for Microwave Medical Applications

This letter proposes a general formula to determine the amount of compound required to produce water–oil-based phantoms that can emulate the electrical properties of a specific body tissue at microwave frequencies. The existing process to produce such a phantom usually involves mixing together a number of different materials, where the proportion of each compound needs to be known a priori to reproduce the dielectric properties of a specific tissue. In this letter, we first investigate the dielectric variation of the mixture by changing the proportion of each compound over a wide frequency band. By utilizing Lichtenecker's logarithmic mixture formula, the gradient descent iterative optimization method is applied to train the relations obtained, and a formula that determines the amount of each compound required to produce a phantom given a specific tissue type is derived. The formula is verified by constructing representative tissues of the human head, with the durability and fidelity of the produced phantom also analyzed.