介质透镜加载的渐变槽线天线的脉冲时空域聚焦研究

Tapered slot antenna, which is featured by wide impedance bandwidth, high gain, good time-domain performance, and etc., has great potential for UWB impulse systems. However, at the high end of the operating frequency band, the antenna radiation pattern varies dramatically with frequency and eventually leads to the split in the main lobe of the radiation pattern. The unstable radiation characteristics cause distortion of the radiation impulses. All of these defects restrain the overall bandwidth and impulse application of the antenna. The project will undertake investigation on impulse excited tapered slot antenna loaded with dielectric lens. By loading dielectric lens for focusing the radiation pulses simultaneously in the time and space domain, the antenna will have an ultra-wide bandwidth and high waveform fidelity and therefore the aforementioned problems will be solved. The research can be divided into five progressive parts, including the impulse radiation characteristics of the tapered slot antenna, the time-space domain impulse focusing of dielectric lens, the time-space domain impulse focusing of tapered slot antenna loaded with dielectric lens, the time-space domain impulse focusing of tapered slot antenna array loaded with dielectric lens, the time-space domain impulse focusing of reflector antenna excited by tapered slot antenna loaded with dielectric lens. Through the investigation on the time-space impulse focusing of the tapered slot antenna loaded with dielectric lens, this project aims to design some tapered slot antennas with ultra-wide impedance bandwidth, high pulse fidelity and stable radiation performance, and realizes systematic and in-depth analysis, design and application for the tapered slot antenna loaded with dielectric lens.

渐变槽线天线具有阻抗频带宽、增益高、时域特性好等优点，在超宽带脉冲系统中具有较大应用潜力。然而，在阻抗频带的高频端，该天线的方向性图随频率剧烈变化且主瓣发生分裂，辐射特性的不稳定导致辐射信号存在严重波形失真，限制了天线的整体工作带宽和脉冲应用。本项目对脉冲激励的介质透镜加载的渐变槽线天线展开研究，通过加载介质透镜对辐射脉冲在时域和空域同时聚焦，使加载天线具有超宽带高保真的脉冲辐射，从而解决上述问题。研究内容包括层层递进的五部分：渐变槽线天线的脉冲辐射特性；介质透镜的脉冲时空域聚焦；介质透镜加载的渐变槽线天线的时空域聚焦；介质透镜加载的渐变槽线天线阵列的时空域聚焦；介质透镜加载的渐变槽线天线馈电的反射面天线的时空域聚焦。本项目旨在通过研究介质透镜加载的渐变槽线天线的脉冲时空域聚焦，设计出超宽带、高保真、稳定辐射的渐变槽线天线，实现对介质透镜加载的渐变槽线天线系统而深入的分析、设计和应用研究。

为研究并解决渐变槽线天线在阻抗频带的高频段波瓣发生分裂、脉冲辐射场波形存在严重波形失真的问题，本项目对脉冲激励的介质透镜加载的渐变槽线天线展开了研究。以介质透镜加载的渐变槽线天线的时空域聚焦特性为关键研究内容，本项目研究了渐变槽线天线的脉冲辐射特性、介质透镜的脉冲时空域聚焦特性、介质透镜加载的渐变槽线天线的时空域聚焦特性、介质透镜加载的渐变槽线天线阵列的时空域聚焦特性等内容。在对渐变槽线天线的脉冲辐射特性和介质透镜的脉冲传输特性进行理论分析和仿真验证的基础上，本项目设计、加工并测试了几款介质透镜加载的不同渐变形状的渐变槽线天线。其中金属柱-空气孔人工介质透镜加载的高斯渐变槽线天线，相比较无加载的同尺寸天线，在工作频带的高频端9-24.7GHz的范围内实现了最高为6.4 dB的增益提高，将主辐射方向的偏移抑制在2度以内，明显改善了天线高频段的波瓣分裂现象，实现了超宽带、高保真、稳定的脉冲辐射。由于加载天线在工作频带的高频段主辐射方向基本没有偏移，因此加载天线作为天线阵列单元时，可以有效降低单元之间的互耦，保证天线阵列辐射主向的稳定性。