Optical measurement of tissue conductivity in microwave range with cell-level resolution

在这一年中，开发了通过使用毫米波雷达来估计复介电常数的技术。测量系统由载物台、雷达模块和指示器组成。通过载物台和指示器可精确调整雷达和物料的位置。在测量过程中，金属板用于校准，然后通过改变距离进行多次测量。用丙烯酸板测试了其性能。复介电常数的测量结果与其他文献的结果吻合较好。随着材料介电特性测量技术的发展，通过在不同方向上移动物体可以得到材料介电特性的分布。同时，利用雷达和角反射器评估了毫米波在材料内部的穿透损耗。据观察，毫米波在材料内部衰减得相当快。预计当使用毫米波作为泵浦波来照射材料时，能量损失将高于微波范围内的能量损失。因此，毫米波范围内的微尺度结构的电导率也有望被估计。此外，还提出了利用微波对水化状态进行无创监测的技术，这些成果已作为期刊/会议论文发表。

In this year, the technology of estimating the complex permittivity by using the millimeter wave radar was developed. The measurement system was build with the stage, radar module, and the indicator. The position of radar and the material can be adjusted precisely with the stage and indicator. During the measurement, the metal plate was utilized for calibration and then the measurements were conducted several times by changing the distance. Acrylic plate was used to test the performance. The measured complex permittivity showed good agreement with the results in other works. With the developed technology of estimating the dielectric property of materials, the dielectric property distribution can be imaged by moving the object in difference directions. Meanwhile, the penetration loss of the millimeter wave inside the materials was evaluated by using the radar and the corner reflector. It was observed that the millimeter wave attenuates quite fast inside the material. It is expected that when using the millimeter wave as the pump wave to illuminate the material, the energy loss will be higher than that in the microwave range. Therefore, the conductivity of the micro-scale structure in the millimeter wave range is also expected to be estimated. Besides, the technology by using the microwave to noninvasively estimate the hydration status monitoring was proposed.These achievements have been published as journal/conference papers.