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

在这一年中，利用毫米波雷达估算复介电常数的技术得到了发展。测量系统由舞台、雷达模块和指示器组成。雷达和物料的位置可以通过舞台和指示器精确调整。在测量过程中，利用金属板进行校准，然后通过改变距离进行多次测量。采用亚克力板进行性能测试。所测复介电常数与其他文献的结果吻合较好。随着材料介电特性估计技术的发展，可以通过对物体进行不同方向的运动来成像材料介电特性的分布。同时，利用雷达和角反射器对材料内部毫米波的穿透损耗进行了评估。据观察，毫米波在材料内部衰减得非常快。预计以毫米波作为泵浦波照射材料时，其能量损失将高于微波范围。因此，微尺度结构在毫米波范围内的电导率也有望得到估算。此外，提出了利用微波无创评估水化状态监测的技术。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.