Experimental Verification of Microwave Head Imaging System Using Phantoms Fabricated from Artificial Tissue-Mimicking Materials

This paper presents microwave head imaging for the detection of tumours and experimental verification using a semi-solid complex multilayer head phantom. Phantoms are an inevitable part of medical diagnosis for obtaining an optimum design before trials in humans. Simple chemical compositions are used to create a material with electrical characteristics that are identical to those of sensitive human brain tissues. The artificially fabricated soft tissues are housed in a man-made substance that has a human skull-like form. This paper describes advancements in the development and measurement of a head phantom, devoted to the testing of a microwave-based head imaging in a realistic laboratory-controlled configuration for brain tumour detection. Dielectric property measurements are performed using a vector network analyser (VNA) with a dielectric probe arrangement and an antipodal Vivaldi antenna (48 mm x 21 mm) with a resonance frequency of 4 GHz. A total of 201 measurements were taken at room temperature (25 degrees C), and a frequency range of 1-6 GHz was used for electrical characterization of the phantom. Measurements were taken multiple times per day, and the average value of the dielectric properties of the phantom components mimicked actual head tissues. The measured reflection coefficient (S11) value with the tumour was -28 dB and that without the tumour was -33 dB for a tumour radius of 10 mm. These measured parameters were used to construct an image in MATLAB using different confocal imaging algorithms. The experimental results for the final phantom product emulated the properties of the required tissues and the location of the tumour.