口径天线瞬态辐射特性的研究

为了在时域研究超宽带口径天线的瞬态辐射特性，利用时域有限差分方法在平面波正投射、斜投射及柱面波投射于不同尺寸和形状的口径面的情况下，对口径面上的场进行了计算，进而得出该口径天线的辐射场。将通常天线的方向图扩展为可用于超宽带天线的空时方向图，并在不同激励的情况下用空时方向图描述了激励脉冲在自由空间展布的宽度与天线口径几何尺寸、形状和主辐射面的辐射波形之间的关系，得出改变口径面的形状和大小可以改变口径面的辐射特性的结论，为理解超宽带口径天线辐射特性并为进一步设计该类天线提供了理论依据。

Research on Transient Radiated Characteristics of Aperture Antennas

In order to investigate the transient radiated characteristics of the ultra-wide-band (UWB) aperture antennas in time-domain, the finite-difference time-domain numerical method was used to calculate the aperture field under the condition that the plane waves had front, slanting, and cylindrical waves project on the aperture with various size and shape, and then the radiation field of the aperture could be obtained. The conventional antenna pattern was extended to the space-time pattern which can be used in UWB antennas, then the relationship between the radiated waveform in E-plane and H-plane and the impulse duration in free space and the aperture shape and size could be described by the space-time pattern in different exciting conditions. In the end, a conclusion that the aperture radiated characteristics could be changed through varying the aperture size and the shape was reached. The research provided a theoretical basis for understanding the transient radiated characteristics of aperture antennas and helping engineers to design this type of antennas.