A study on propagation characteristics of optically controlled millimeter waves guided along the H-guide and its application to leaky wave antenna

利用基于精确导波理论的数值计算方法，研究了漏毫米波在含有光致等离子体层的半导体H导中的传播特性。通过色散曲线的数值算例，揭示了导模到漏波的高速转变机制。首先用Muller方法求出了复本征值方程的解，然后求出了每个方向的复传播常数和波数。通过计算的潮流矢量，图形化地揭示了泄漏波的性质。从泄漏波的矢量图中我们发现，平均功率密度的方向随等离子体密度的变化而剧烈变化，这是由于照明强度和工作频率的影响。在这项研究中，我们获得了在26.5-40 GHz范围内使用硅H导漏波天线设计的基础数据。我们还计算了作为半导体插入H导中的GaAs的传输特性，该特性具有较快的响应性，并且对于较高的频率范围，如60 GHz，有很好的实用前景。作为实验测试，我们测量了H波导喇叭的漏波辐射，并考察了由于照射强度的影响而产生的指向性特性。现阶段的测量结果与理论结果存在一些差异，并对实验条件进行了改进。

The propagation properties of leaky millimeter waves in the semiconductor H-guide containing optically induced plasma layer have been investigated by utilizing the numerical calculation based on the exact guidedwave theory. The mechanism of high-speed transition from guided modes to leaky waves has been shown with the numerical example of dispersion curves. First we derived the solution to the complex eigenvalue equation by Muller method, and then obtained the complex propagation constant and wave numbers for each direction. With the calculated power flow vectors, the property of leaky waves was revealed graphically. From the figures of the vector form of leaky waves, we found that the direction of average power density drastically changed with the plasma density due to illuminating intensity and also with the operating frequency. In this research we obtained the basic data for designing the leaky wave antenna using a silicon H-guide in the range between 26.5 and 40GHz. We also calculated the propagation characteristics for GaAs as a semiconductor inserted into the H-guide, which was expected to be fast response, and for higher frequency range such as 60GHz that was promising for a practical use. As an experimental trial, we measured the leaky wave radiating from the horn of H-guide, and examined the directivity characteristics due to the illuminating intensity.Some differences between the measurement and the theoretical results have been left at this stage, and their improvement for the experimental conditions are the following assignment.