The separation distance between upper and lower plates,and the width of plates of TEM horn antenna with con-stant impedance changes linearly along the axial direction,while the wide ratio of driver port and terminal port is the same. Dif-ferent from constant impedance TEM horn antenna,the plate distance between upper and lower plates of the exponential tapered TEM horn antenna is exponentially graded along the axial direction. It is found in the research that when the different plate width gradient forms of exponential tapered TEM horn antenna are adopted,the best standing wave ratio and its VPP(peak to peak value of the far-field pulse in the axial direction)are the best. If the antenna length along the axial direction and the height of end port is a constant value,the TEM horn antenna''''VPP changes with the width of end port. When the end port impedance is 215 Ω,the VPP is the maximum.%恒阻抗TEM喇叭天线的上、下板之间的间距、板的宽度沿天线轴向呈线性渐变,且喇叭天线的驱动端口、末端端口的宽高比相同.与恒阻抗TEM喇叭天线不同,指数渐变型TEM喇叭天线上下极板之间的间距沿轴向呈指数渐变.研究发现,当指数渐变型TEM喇叭的极板宽度采用不同的渐变形式时,极板宽度线性变化型TEM喇叭天线的驻波比最佳,主射方向远场脉冲峰峰值最大.当天线轴向长度、末端端口高度一定时,天线主射方向远场脉冲峰峰值随着天线末端端口宽度的增大而增大;当末端端口宽度达到一定值时,脉冲峰峰值达到最大值,继续增大末端端口宽度,脉冲峰峰值减小;当天线主射方向远场脉冲峰峰值达到最大值时,天线末端端口阻抗值为215 Ω.
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