同轴探针对称激励矩形波导模式谱图研究

通过理论分析证明，同轴探针对称激励矩形波导时，其模式谱图中不存在引起合成场结构不对称的高次模TE20及TE01模。应用分式线性变换检测法进行了对比测试，验证了理论分析结果的正确性。对聚四氟乙烯样品，在7—16GHz频带内测量其复介电常数均有较高的测量精度。实验表明，在一定条件下，标准三公分波导工作频率可高达16GHz，如果取波导宽窄边比r=3，工作频率可达19GHz。所得结果对于微波材料宽带测量具有实用价值。

Mode-Spectrogram of the Rectangle Waveguide Symmetrically Excited by the Coaxial-Line Probe

In this paper, we first prove theoretically that the higher-order modes, such as TE20 and TE01 , with asymmetry electric fields do not exist in its nsode-spectrogram, when the rectangle waveguide is symmetrically excited by the coaxial-line probe. By using the linear fraction transformation method, the compared measurements are made, which verify the validity of the theoretical results. For the Teflon samples, the precision for measuring their complex dielectric constant in the frequency band 7 - 16GHz is high. These measurement results also indicate that the operating frequency of the standard 3cm rectangle waveguide can reach 16GHz under some special conditions. If the aspect ratio of the rectangle waveguide r = 3, its operating frequency is able to achieve 19GHz. Our conclusion is of practical value for measuring the complex permittivity of microwave materials in broad band.