SPACE-WAVE CHARACTERISTICS OF MILLIMETER-WAVE GUIDES AND DEVELOPMENT OF LEAKY-WAVE ANTENNAS WITH HIGH PERFORMANCE

研究了由金属波导或平面电路传输线构成的泄漏毫米波天线的发展，特别是短节加载的脊形矩形波导。为了设计天线，必须准确地分析短节加载波导的泄漏特性，因此我们首先提出了一种改进的模式匹配方法，适用于分析目前具有许多奇异场边缘的波导。然后计算了结构参数对泄漏的依赖关系，建立了低副瓣辐射高性能天线的设计方法。作为设计实例，设计并制作了副瓣电平为-30d B的泰勒分布天线。对其辐射方向图的测量充分证明了该天线的有效性。但是，fdtd分析表明，在Proo…中，高阶沟道导漏模略有被激发，同时也存在期望的漏模。导轨结构更加紧凑。从辐射方向图的角度来看，这一事实并不严重，但从激励效率的角度来看，这一事实是重要的。因此，对短节加载波导的结构进行了改进，将短节部分安装在脊部。改进后的导轨实现了单模运行。再次建立了基于该改进导轨的低副瓣天线设计方法，并通过实验验证了该方法的有效性。最后，设计并制作了包括馈电电路的阵列天线。测试结果证实了该阵列天线的实用性。而对于平面电路传输线，在接地平面和介质基板之间引入横向导体壁和空气层对于高性能的漏波天线是非常有用的。较少

The development of leaky millimeter-wave antennas, which is constructed by a metal waveguide or a planar-circuit transmission line, especially a stub-loaded ridge-rectangular waveguide, has been investigated. For designing antennas, we should analyze accurately the leakage properties of the stub-loaded waveguide and so we have first developed an improved mode-matching method suitable to the analysis of the present waveguie that has many singular-field edges. Then the dependence of the structural parameters on the leakage is calculated and a design method for high-performance antennas with low-sidelobe radiation is established. As a design example, an antenna with the Taylor distribution of -30dB sidelobe level has been designed and fabricated. The measurement of its radiation pattern fully proves the effectiveness of the present antenna. But, the FDTD analysis shows that the higher-order channel-guide leaky mode is a little bit excited, together with the desired leaky mode in the propo … More sed guide structure. This fact is not so serious from the viewpoint of the radiation pattern, but is important from the viewpoint of the excitation efficiency.Therefore the structure of the stub-loaded waveguide has been improved, of which the stub portion is installed into the ridge portion. As a result, the single-mode operation has been realized in the improved guide. The design method for a low-sidelobe antenna based on this improved guide has been again established and its effectiveness has been verified experimentally, too. Finally, the array antenna including a feeding circuit has been designed and fabricated. The measured results confirm the usefulness of the array antenna. These results provide the possibility for using the present leaky-wave antenna practically.While as for planar-circuit transmission lines, it is concluded that introducing lateral conductor walls as well as an air layer between the ground plane and the dielectric substrate is very useful for a high-performance leaky-wave antenna. Less