TEM喇叭天线辐射机理分析和优化设计

在频域和时域研究了TEM喇叭天线的辐射机理。在频域，高频信号激励的TEM喇叭表现为口径天线的辐射特性，具有良好的方向性；低频信号激励的TEM喇叭可视作偶极子天线，具有全向辐射特性；在时域，脉冲激励的TEM喇叭天线辐射场由四个子波叠加构成，在不同方向上，各个子波的波形和相对时序不同，导致不同方向上辐射场波形也不相同。根据辐射机理研究结果，提出了一种TEM喇叭天线末端加载设计并给出了其优化设计方法，有效地改善了天线主轴辐射性能，提高了辐射因子和天线效率。

Radiation mechanism analysis and optimized design of TEM horn antennas

The radiation mechanism of a TEM horn antenna both in time and frequency domain is researched. The TEM horn fed by the high-frequency signal behaves as an aperture antenna with favorable directional radiation capability and the TEM horn fed by the low-frequency signal behaves as a dipole antenna with omnidirectional radiation field. In time domain, the radiation field of TEM-horn antenna fed by a short impulse consists of four sub-waves. The waveform and comparative time sequence of every sub-wave is different in every direction, and that leads to dissimilar radiation waveform to every direction of antenna. Based on the research result, we propose an end-loading optimizing method for TEM-horn-antenna design. In this way, the radiation performance on boresight and the efficiency of the TEM horn are observably improved.