Research On The High Power Microwave Power Dividing And Phase Shifting Devices And Leaky Wave Antenna Array

High power microwave(HPM)systems usually consist of pulsed power subsystems,HPM sources,transmission subsystems,and radiation subsystems.With the development of related technologies,the peak power of HPM sources continues to increase,and the performance requirements of the transmission and radiation subsystems are accordingly increased.At present,the relatively mature HPM radiating components are large-aperture reflector antennas.This kind of antennas has high gain and large operating bandwidth with simple configuration,but their mechanical beam scanning operation is slow and they are hard to be integrated into carrier platforms with conformal shape.Compared with the mechanically-scanned reflector antennas,the phased array antennas have the advantages of rapid beam scanning and agile beam shape adjusting.The operating characteristics such as gain,efficiency,scanning range and accuracy of the phased array are directly determined by the performance of the power divider,phase shifter,and transmitting antennas.It has a great theoretical significance and practical value to study high power low loss components,which include power-dividing/phase-shifting networks and high radiation efficiency antennas.In this thesis,at first,the design method of high power planar multiple channel divider is studied.According to the field distributing characteristics that the specific sectorial waveguide mode is uniform along the circumferential direction,a design scheme for multiple channel equally-divided power dividers is proposed.The output amplitude uniformity is improved by adjusting the central angle of the output channels,and the output phase consistency is improved by introducing phase adjusting structures.The theoretical analysis and simulation verification is given.According to the proposed design method,an X-band 48-channel planar waveguide power divider is designed and its transmission characteristics are experimentally studied.The results show that the transmission efficiency of the power divider reaches 95.7%,the output power consistency reaches 0.28dB,the phase balance is 4.6°,and the power capacity reaches 2.7GW.This scheme can realize planar multi-channel equal magnitude and in-phase power dividing in high power applications.Secondly,the design method of leaky waveguide antenna with high power capacity and high aperture efficiency is studied.The design theory of traditional leaky wave antenna is summarized.The design process is improved by considering the influence of the high aperture efficiency condition.The improved design method is employed to design the metal post side-loaded leaky waveguide antenna.An X-band 48-channel leaky waveguide antenna is designed.The antenna structure is fabricated and the radiation characteristics are experimentally verified.The return loss of the leaky wave antenna is better than 25 dB,the gain at the central frequency point is 38.75 dB,the corresponding aperture efficiency is 80.7%,and the power capacity is 3.1 GW.Afterwards,a non-contacting high power waveguide phase shifter design scheme is proposed based on the semiconductor photoconduction effect.The operating principle of the optically controlled phase shifter is theoretically analyzed.The mathematical formulae of the phase shift and insertion loss with respect to the semiconductor conductivity and structure dimensions are provided.Several available semiconductor materials and light sources are tested,and one combination is selected which can achieve the highest phase shift.The feasibility of the optically controlled phase shifter design scheme is verified.Finally,the design method of high-isolation waveguide combiner is theoretically analyzed.Based on the theory of network analysis,three design methods are proposed to improve the isolation of power combiners.The equivalent circuit modeling of waveguide-coaxial magic-T is performed,and the analytical expressions of the circuit element parameters are derived.Meanwhile,the design scheme of high isolation waveguide combiner with compact cross-sectional size is proposed on the basis of the conventional 3dB hybrid ring structure.A four-way coaxial-waveguide power combiner operating in the X-band is developed with a combining efficiency of 98.9%within a cross-sectional dimension of 0.71?×0.74?,the relative bandwidth is 12%,the isolation is better than 22 dB,and the power capacity of 13.7 kW.The above results show that the scheme realizes power combining function within a compact cross-section under high power conditions.