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

这一年，利用毫米波雷达估计复介电常数的技术得到了发展。测量系统由工作台、雷达模块和指示器组成。雷达和物料的位置可以通过工作台和指示器进行精确调整。在测量过程中，利用金属板进行标定，然后通过改变距离进行多次测量。用亚克力板材对其性能进行了测试。测得的复介电常数与其他工作的结果吻合较好。随着材料介电性能估计技术的发展，可以通过在不同方向上移动物体来获得介电性能分布的图像。同时，利用雷达和角反射器对毫米波在材料内部的穿透损失进行了估算。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，毫米波范围内微尺度结构的电导率也有望得到估计。此外，还提出了利用微波无创监测水化状态的技术，这些成果已发表在期刊/会议论文中。

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.