Research Of High Power Vivaldi Antenna

Ultra-wide spectrum high power microwave has a broad application prospects on ground penetrating radar, high-power microwave weapons, electronic countermeasures, electromagnetic compatibility and so on. Ultra-wideband vehicle stopper system is one of the non-lethal high power microwave weapon for destroying the engine electronic control system of a target vehicle, making the target vehicle stop or slow down. The system mainly consists of three parts: a Marx generator, an oscillation structure storing energy, an ultra-wideband high power antenna.The radiation part of Ultra-wideband vehicle stopper system is the high power and ultra-wideband antenna. The signal from the equipment forming high power pulse is a narrow pulse and has an ultra-wide spectrum. Its energy mainly distributes in the low frequency range, and the lowest frequency is from 300 MHz to 400 MHz. Therefore, the first step is to choose an ultra-wideband antenna as radiator and extend its bandwidth to lower frequency. The operating voltage of antenna is tens of kilovolts or higher, so it’s significant to prevent concentrated electromagnetic field from breakdown. The entire system must be compact and integrated on vehicle, requiring that the antenna is of planar and miniature structure. For the antenna directionally radiating to target vehicle, design of antenna with high gain and good directivity is difficult but significant. So the main content of the paper is to propose an ultra-wideband antenna with performance of high voltage resistance, high gain, low profile and miniaturization.At the start of this paper, it introduces working mechanism, application prospect and research status of ultra-wideband vehicle stopper system, proposes design index for radiation antenna, and then describes research background of high power ultra-wideband antenna. For these design requirements of the radiation antenna, the specific work of this paper includes the following aspects. Firstly, advantages and disadvantages of ultrawideband antenna including biconical antenna, horn antenna and slot antenna are synthetically considered, then Antipodal Vivaldi antenna with opposed structures is chosen as the radiator of the system. Secondly, the basic theory of Antipodal Vivaldi antenna design is introduced, its initial structure is designed by simulation, following physical manufacture and measurement. Thirdly, the modification with transverse slots loaded on the edge of every patch and longitudinal slots loaded on tail of the two patches from initial antenna above improves performance in the lower frequency range and reduces the size of the antenna, and circulated tips on the end of transverse slots structure for avoiding groove edge reflection reduces VSWR and increase gain slightly; without increasing the size of the antenna above, parasitic elliptical patch on the radiation aperture improves the gain to a certain level. Fourthly, for the final opposed Vivaldi antenna and coplanar Vivaldi antenna, their power capacity is estimated respectively by theoretical analysis and by simulated electric field distribution. Finally, the main research work and innovation of this paper are summarized, following that flaws of designed antenna and the next assignment are proposed.