A 3-D-Printed High-Dielectric Materials-Filled Pyramidal Double-Ridged Horn Antenna for Abdominal Fat Measurement System

This article presents a novel 3-D-printed, pyramidal double-ridged horn antenna, filled with a high-dielectric material comprising a mixture of linseed oil and titanium oxide, for biomedical applications. In particular, this investigation explores the use of the antenna design to measure the abdominal fat layers of the human body. The antenna is designed to operate at the low-frequency microwave bands and complemented with an absorber layer at the aperture to improve directivity. The proposed method aims to assess the fat layer thicknesses based on an analysis of the variations of the reflection coefficients. The system has been calibrated and validated based on a number of numerical time-domain simulations, as well as experimental analysis. Assessment of the first transition point in the reflection coefficient spectrum has successfully predicted the rate of magnitude change caused by different layer thicknesses (e.g., oil and fat). Comparing coefficient spectra from various simulation experiments has allowed for eliminating the interferences arising from mismatches with the skin and muscle layers, resulting in the measurements of the fat layer thicknesses through the remaining power change rate.