Design Of Ultra-wideband TEM Horn Antenna And Study Of Aperture Radiation Characteristics

The ultra-windcband TEM horn antenna is a typical high-power pulsed radiation antenna,which has the obvious advantages of good directivity,high peak power capacity and simple structure.However,due to the sudden truncation of the end of the TEM horn antenna aperture,a large end reflection current is gencrated,which makes the antenna's low-frequency radiation capability insufficient.This paper mainly studies the end reflection problem from two aspects:antenna port characteristics and time-domain radiation characteristics.The research work of the thesis mainly has the following points:1.The radiation charactcristies of aperiodic pulses are analyzed from the time domain perspective.Using the maximum Poynting vector and the integrated Poynting vector,the peak power and energy radiated into space are calculated,and then the peak power gain and energy gain of the pulsed radiation antenna are analyzed.2.In order to improve the peak power transmission efficiency of the unbalanced to balanced conversion balum,and improved gradient balum structure was designed.The S11 parameter of the balun structure is less than-10dB in the entire working band,and the peak power transmission efficiency is equal to 93.47%;3.In order to improve the defect of large reflected current at the end of the antenna aperture,a distributed end-loaded born antenna was designed.The simulation results show that compared with the born antenna without end loading,the low-frequency impedance bandwidth of the distributed end loading antenna is extended by 331MHz,the energy radiation efficiency is inerensed by 17.2%,the peak power radiation effiency is increased by 2.3%,and the antenna is miniaturized.