Zhou Lixiao, Truong Van Doi, Yoon Jonghun
Department of Mechanical Design Engineering, Hanyang University, 222, Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
Department of Mechanical Engineering, Hanyang University, Ansan 15588, Republic of Korea.
Sensors (Basel). 2025 Sep 5;25(17):5547. doi: 10.3390/s25175547.
Accurate and non-invasive assessment of fat and muscle composition is crucial for biomedical monitoring to track health conditions in humans and pets, as well as for classifying meats in the meat industry. This study introduces a cost-effective, multifunctional ultra-wideband microwave system operating from 2.4 to 4.4 GHz, designed for rapid and non-destructive quantification of fat thickness, muscle thickness, and fat-to-muscle ratio in diverse ex vivo samples, including pork, beef, and oil-water mixtures. The compact handheld device integrates essential RF components such as a frequency synthesizer, directional coupler, logarithmic power detector, and a dual-polarized Vivaldi antenna. Bluetooth telemetry enables seamless real-time data transmission to mobile- or PC-based platforms, with each measurement completed in a few seconds. To enhance signal quality, a two-stage denoising pipeline combining low-pass filtering and Savitzky-Golay smoothing was applied, effectively suppressing noise while preserving key spectral features. Using a random forest regression model trained on resonance frequency and signal-loss features, the system demonstrates high predictive performance even under limited sample conditions. Correlation coefficients for fat thickness, muscle thickness, and fat-to-muscle ratio consistently exceeded 0.90 across all sample types, while mean absolute errors remained below 3.5 mm. The highest prediction accuracy was achieved in homogeneous oil-water samples, whereas biologically complex tissues like pork and beef introduced greater variability, particularly in muscle-related measurements. The proposed microwave system is highlighted as a highly portable and time-efficient solution, with measurements completed within seconds. Its low cost, ability to analyze multiple tissue types using a single device, and non-invasive nature without the need for sample pre-treatment or anesthesia make it well suited for applications in agri-food quality control, point-of-care diagnostics, and broader biomedical fields.
准确且无创地评估脂肪和肌肉成分对于生物医学监测至关重要，这有助于追踪人类和宠物的健康状况，同时也可用于肉类行业的肉类分类。本研究介绍了一种经济高效的多功能超宽带微波系统，其工作频率为2.4至4.4 GHz，旨在对包括猪肉、牛肉和油水混合物在内的多种离体样本中的脂肪厚度、肌肉厚度以及脂肪与肌肉比例进行快速无损定量分析。这款紧凑的手持设备集成了诸如频率合成器、定向耦合器、对数功率探测器和双极化维瓦尔第天线等关键射频组件。蓝牙遥测技术实现了向基于移动设备或个人电脑的平台进行无缝实时数据传输，每次测量只需几秒钟即可完成。为提高信号质量，应用了一种结合低通滤波和Savitzky-Golay平滑处理的两阶段去噪流程，在保留关键光谱特征的同时有效抑制了噪声。该系统使用基于共振频率和信号损耗特征训练的随机森林回归模型，即使在样本条件有限的情况下也能展现出较高的预测性能。在所有样本类型中，脂肪厚度、肌肉厚度以及脂肪与肌肉比例的相关系数始终超过0.90，而平均绝对误差保持在3.5毫米以下。在均匀的油水样本中实现了最高的预测精度，而猪肉和牛肉等生物结构复杂的组织则带来了更大的变异性，尤其是在与肌肉相关的测量中。所提出的微波系统被视为一种高度便携且省时的解决方案，测量在数秒内即可完成。其低成本、能够使用单一设备分析多种组织类型以及无需样本预处理或麻醉的无创特性，使其非常适合用于农业食品质量控制、即时诊断以及更广泛的生物医学领域。
