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

利用精确导波理论的数值计算方法，研究了泄漏毫米波在含光诱导等离子体层的半导体h波导中的传播特性。通过色散曲线的数值算例说明了从导模到漏波的高速过渡机理。首先用Muller法推导了复特征值方程的解，然后得到了各方向的复传播常数和波数。利用计算得到的功率流矢量，图形化地揭示了漏波的特性。从泄漏波的矢量图中，我们发现平均功率密度的方向随着等离子体密度和工作频率的变化而剧烈变化。本研究获得了设计26.5 ~ 40GHz硅h波导漏波天线的基本数据。我们还计算了GaAs作为插入h波导的半导体的传播特性，预计会有快速响应，以及更高的频率范围，如60GHz，有望用于实际应用。作为实验试验，我们测量了h型导角的漏波辐射，并研究了由于照射强度的影响，漏波的指向性特性。在这个阶段，测量结果和理论结果之间有一些差异，它们在实验条件下的改进是下面的任务。

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.