| With the continuous improvement of theory and the uninterrupted progress of modern technology,the output power of a single high-power microwave source has reached the level of GW or even more than ten GW.Limited by the inherent physical mechanism,the output power of the high-power microwave source has fallen into a bottleneck in further improvement.In order to achieve higher radiation efficiency,space power coherent combining technology has become a hot research topic in the field of high-power microwaves in recent years.In response to this development trend,combined with the application requirements of high-power microwave technology,the current design and development of high-power microwave antennas mainly focus on four aspects: arraying,compactness,beam scanning capability,and cost control.Compared with the high-power microwave antennas commonly used for beam scanning at present,waveguide slot antennas are widely used due to their low profile,easy conformal,compact structure and easy array,simple processing and low cost.However,the waveguide slot antenna is affected by the mutual coupling between the slot array elements,and the beam scanning range is slightly narrower than other antennas.Based on this,this article aims to expand the beam scanning range of the waveguide slot array antenna,and carries out the research on the high-power waveguide slot array antenna with wide-angle phase scanning function.The main contents are as follows:1.First,analyze the radiation principle of different forms of slot elements,and select the narrow-side oblique slot as the radiation element of the array antenna in this paper according to the needs.Aiming at the two different forms of slot normalized conductance extraction models of traveling wave array and standing wave array,the normalized conductance expressions of the two arrays are deduced by equivalent circuit method and power transmission method.Through simulation and comparison,it is found that the conductance function obtained by using traveling wave extraction is more accurate when designing a large slot array antenna.The influence of the structural parameters of the narrow-side oblique slot on the radiation characteristics of the slot unit is studied and summarized,which provides a certain reference for the selection of structural parameters in the subsequent design of the narrow-side slot array antenna.2.Then,in order to solve the problem of the complicated and lengthy power division feed network of the current high-power microwave waveguide slot antennas due to the end feed,which causes a part of energy waste,the corresponding intermediate feed joints are designed for the traveling wave array and the standing wave array to form an intermediate feed.Electric line/standing wave slot array.At the same time,a new type of additional structure—isolation barrier is introduced into the array,which can not only suppress the cross polarization of the narrow-side oblique slit,but also improve the isolation between the slit array elements.Finally,set 8.4GHz as the center frequency,when the port reflection coefficient is less than-10 d B and the gain is reduced by 3d B,the 4m standing wave array can achieve ±42° scanning on the H surface,and the 4m traveling wave array can achieve ±45° scanning on the H surface.3.Finally,a compact rotating waveguide phase shifter is designed to realize one-dimensional scanning of the waveguide slot array antenna.The phase shifter is composed of a waveguide narrow-side slot bridge,a stepped metal diaphragm line circular polarization converter,and a circular polarization reflector.The simulation results show that the phase shifter can achieve continuous linear phase adjustment.At the center frequency-8.4GHz,the energy transmission efficiency at the point is greater than 99.5%,and the power capacity in vacuum is about 80 MW.It solves the problem of resonant operating frequency and sudden drop in power capacity of the existing rotary waveguide phase shifter.Finally,a radial power divider is designed according to the microwave source output microwave mode and the required feed mode of the antenna array.This power divider realizes the mode conversion and also completes the constant amplitude power division of the input microwave,and the mode conversion at the center frequency point The efficiency is greater than 99%,and the power capacity under vacuum conditions is about 4.2 GW. |
