Research On Some Key Technologies Of High-Power Microwave Array Antenna

With the rapid development of high-power microwave?HPM?technology,the output power of HPM sources has increased from the Megawatt level to the Gigawatt level.At the present,the common HPM antennas are facing many problems that need to be solved urgently.In particular,traditional mechanical beam scanning is hard to be competent to the rapidly changing modern battlefield situation,which also poses new challenges to HPM antenna technology.Due to differences between HPM technology and traditional microwave in term of sources,transmission waveguides,power dividers,phase shifters,antennas,etc.,problems may be encountered in following the traditional microwave antenna design method,such as power capacity.Based on the actual application requirements,this paper conducts research on several key technologies of HPM array antennas in order to solve the problems of HPM antennas in terms of gain,efficiency,electronic beam scanning,and power capacity.The main content includes the following five parts:1.Research of Planar Reflectarray and Compact Slot Array Antenna for HPM ApplicationThe basic theory of planar reflectarray antenna is described.The formula of phase compensation of planar reflectarray is deduced,and common methods for designing reflectarray elements are introduced.The critical slot width is derived from the slot aperture field distribution as a guidance to increase the gap power capacity.The phase distribution of the compact slot array is studied,and a fast optimization algorithm based on analytic hierarchy process?AHP?is proposed.2.Research and Design of Circular Aperture Compact HPM Antenna Based on Phase Cancellation TechnologyInspired by the radial line slot array antenna,a low-profile coaxial cavity was proposed as the feed waveguide for a compact HPM feed antenna,the radial size of the antenna is 0.7?,and it achieves a low profile.The critical slot width is calculated,and power capacity is enhanced by wide slot array.The TM₀₂₀mode is selected as the feed mode for achieving compact aperture,mode-coupling-based principle eliminates discontinuities caused by overmoded coaxial waveguides,and improves the impedance matching of the antenna.From the perspective of the aperture efficiency of the circular aperture reflector and reflectarray antenna,a phase cancellation technique that can realize shaped beam on a compact aperture is proposed.This technology is mainly designed based on the edge illumination level of the feed,the gain of the reflector antenna is increased by 1.9dB compared with the traditional HPM feed,so the aperture efficiency of the reflector antenna is higher.3.Research and Design of Rectangular Aperture Compact HPM Feed Antenna Based on Asymmetric High-Order ModeA checkerboard method is proposed to realize the rapid analysis of the resonant mode of the rectangular cavity,and it is used for the compact structure design of HPM feed based on the mode coupling idea.As a HPM feed,the antenna does not require additional power dividers and mode converters,and its radial length is only 0.82?.The power capacity of wide slot array equipped with the horn cavity has improved 122%compared with the ordinary wide slot array.The Research on symmetry of the asymmetric high-order mode and the alternating arranged slot array of the far-field pattern is carried out.Conformal array technology is used to significantly improve the aperture efficiency of the reflectarray antenna through its shaped beam.Finally,based on the compact structure of the HPM feed,a multi-feed array is proposed to improve the damage effect of the high-power microwave reflector antenna.4.Research and Design of HPM Reflectarray Antenna Based on Energy TunnelingArtificial electromagnetic materials have extraordinary electromagnetic properties has not been found in natural materials,which breaks through the limitations of conventional materials on power capacity.Through the analysis of the equivalent medium theory and the scattering parameter inversion method to analyze the perforated metal film in the microwave band,a sandwiched material with zero dielectric constant is proposed,and the energy tunneling characteristics of this structure are revealed.The robustness to the incident angle and polarization direction of the sandwiched material is studied and analyzed,the structure features frequency and polarization selectivity,wide angle,and phase delay.It can be used for frequency selective surfaces with wide angle and low cross polarization,and a low-profile phase shifter is designed.Based on this,an HPM planar reflectarray antenna is proposed,simulation results show that the power capacity of the unit is 1.6GW/m²,which has the potential for HPM applications.5.Research and Design of Plasma-Reconfigurable HPM Reflectarray Antenna for Electronic Beam ScanningThe interaction between one-dimensional non-magnetized plasma and microwave is studied,the simulation has verified the reconfigurable characteristics of plasma,and a plasmatuning switch based on low-pressure argon discharge is proposed as a HPM RF switch.By adjusting the bias voltage,the state of plasmatuning switch can be switched,and the purpose of controlling the propagation path of incident electromagnetic waves is achieved.A Method of plasmareconfigurable HPM planar reflectarray unit of 1-bit,2-bit and 3-bit are proposed,and is verified by a 1-bit reflectarray unit.A testing platform is built for determining the power capacity of the unit,and the measurement results show that the unit has the application value of a HPM planar reflectarray.Finally,the 13×8reflectarray based on this plasma-reconfigurable unit with electronic beam scanning was verified,the simulation results show that the reflectarray can achieve scan range of±38°.