石墨烯微波/毫米波电磁特性及其表征方法研究

As a new nano-scale electronic material, zero band-gap semiconductor Graphene has great potential in the application of high-frequency electronic devices, and has been widely attracted now. Electromagnetic parameters are the basis of microwave/millimeter wave circuit design, so the measurement of graphene electromagnetic parameters is critical for the development of graphene microwave/millimeter wave circuits. However, due to the unique properties of graphene (i.e. nano-scale dimension,metal-semicondutor, etc.) , the conventional measurement methods are suffered from large error and insufficient sensitivity, or even in vain. That is why there are only a few papers on the characterization of exfoliation graphene base on equivalent circuit model, and is still no report on the measurement of intrinsic electromagnetic parameters, permittivity and permeability, which dramatically constrain the development of graphene circuits. As a result, a multilayer coplanar method is proposed to measuring the electromagnetic parameters of graphene made by chemical vapor deposition (CVD). The nano-fabrication technique is used to fabricate the measurement fixture, and the electromagnetic parameters of graphene are directly extracted by establishing the multilayer dielectric model based on the measurement results. The proposed method can improve the accuracy of measurement results, and obtain the electromagnetic parameters of large area CVD graphene, which are important for the development of graphene microwave/millimeter wave circuits.

石墨烯作为新型纳米电子材料，是目前微波/毫米波器件的研究热点，在高频电子器件领域具有广阔的应用前景。电磁特性是石墨烯微波/毫米波电路研制的基础，因此开展石墨烯电磁特性表征方法研究，对石墨烯微波/毫米波电路的发展至关重要。然而，由于石墨烯具有纳米级物理尺寸和金属半导体特性，传统电磁参数测试方法存在灵敏度低，测试误差大，甚至失效等问题，导致目前仅限于对机械剥离的小面积石墨烯传输线等效电路模型的研究，而对化学气相沉积(CVD)制备的大面积石墨烯本征电磁参数的研究仍未见报道，极大地限制了石墨烯电路设计的灵活性。针对上述问题，本项目提出基于多层介质共面波导结构的石墨烯电磁参数表征方法对CVD制备的石墨烯电磁特性进行表征，采用纳米制造工艺制备测试样品，通过多层介质分析建立模型，从测试结果中直接提取石墨烯微波/毫米波电磁参数。该方法可实现大面积石墨烯的电磁特性表征，为设计石墨烯微波/毫米波电路奠定基础。

石墨烯具有纳米级物理尺寸和金属半导体特性，传统电磁参数测试方法存在灵敏度低，测试误差大，甚至失效等问题，导致目前仅限于对机械剥离的小面积石墨烯传输线等效电路模型的研究，而对化学气相沉积(CVD)制备的大面积石墨烯本征电磁参数的研究相对薄弱，极大地限制了石墨烯电路设计的灵活性。针对上述问题，本项目提出基于多层介质共面波导结构的石墨烯电磁参数表征方法对CVD制备的石墨烯电磁特性进行表征，采用纳米制造工艺制备测试样品，通过多层介质分析建立模型，从测试结果中直接提取石墨烯微波/毫米波电磁参数。研究了多层介质结构微波/毫米波等效参数测试方法，对测试结构进行了仿真和优化设计，验证了方法的可行性；研究了多值解问题及增根自动判别方法，解决了数值计算中的多值问题，编写了自动测试软件；研制了石墨烯测试装置，组建了实验系统，并对其进行了自动测试与数据分析处理。发表论文7篇，并全部被SCI收录，在IEEE IMS等国际会议上做分会场报告4次，申请国内发明专利3项。