在超宽带TEM喇叭天线的设计中，如何改善天线的低频性能是目前研究的关键问题。通过分析天线的阻抗渐变特性与时域辐射特性，设计了一种新型TEM喇叭天线，解决了天线末端反射的问题，提高了天线低频性能。与传统的TEM喇叭天线相比，新型TEM喇叭天线在全频段减小了方向图后瓣，提高了低频时天线辐射主轴增益，拓展了低频带宽。验证实验表明，该天线带宽为160 MHz~2.5 GHz，180 MHz主轴增益2.3 dB，全频段方向图后瓣小于-2 dB，尺寸为48.5 cm×38.1 cm×35 cm，同时兼顾了天线的小型化与低频带宽。

Improving antenna performance at low frequency is the focus of TEM horn antenna research. A new TEM horn antenna was designed by analyzing the impedance gradient and time-domain radiation characteristics of the antenna, to solve the reflection problem at the end of the antenna and improve the low-frequency performance of the antenna. Compared with the typical TEM horn antenna, the new TEM horn antenna designed in this paper reduces the pattern back lobe in the full frequency band, improves the antenna radiation spindle gain at low frequency, and expands the low frequency bandwidth. The antenna size is 48.5 cm×38.1 cm×35 cm. The experimental results show that the return loss at 160 MHz, 2.5 GHz is less than -10 dB and the pattern back lobe is less than -2 dB.