Research On Wideband High-power Microwave Planar Antenna Array

In recent years,with the development of high-power microwave(HPM)field,wideband high-power microwave technology has become one of the hotspots.High power microwave antennas are the most important part of high-power microwave radiation systems.Currently,most high-power microwave antennas are based on narrow-band high power microwave sources.Their bandwidth is usually less than 5%,which is not suitable for wideband HPM field.Therefore,there is an urgent need for high-gain,high-efficiency,miniaturized,low-profile wideband high power microwave antennas.In this context,this paper proposes two low-profile wideband antenna arrays for high-power microwave application,namely wideband high power microwave planar antenna array and wideband high power microwave aperture coupled microstrip antenna array respectively.A wideband power divider based on radial line waveguide is used as feeding network for the both antennas.The feasibility of the two design was verified by theoretical analysis,electromagnetic software simulation and experiments.The research content mainly includes the following aspects:1.Design and experiment of a wideband high-power microwave planar antenna arrayDue to the disadvantages of large transverse size,low aperture efficiency and complicated assembly problems of conventional planar antennas,this paper proposes a compact E-shaped planar antenna array whose center frequency is 2.1GHz,an innovatively method is proposed that connecting the sides of adjacent antenna elements and process them into a whole.By this way,the aperture efficiency of the antenna array is greatly improved,and the radiation characteristics of the antenna are improved.The antenna array achieves a relative bandwidth of 33%(1.72-2.42GHz,VSWR<2)in simulation,the gain in the whole bandwidth is greater than 22.4 d B,and the aperture efficiency is greater than 90%.In cold tests and high power microwave tests,the measured bandwidth of the antenna array is greater than 20%(1.97?2.39GHz),and the gain in the whole bandwidth is greater than 20d B.In addition,stable radiation of microwave signal is realized at 140MW peak power.2.Design and experiment of a wideband high-power microwave aperture coupled microstrip antenna arrayThis paper summarizes some methods and ideas for applying the microstrip antennas to the field of high power microwaves,and proposes a three-layer wideband H-shaped aperture coupled microstrip antenna array with back cavity,whose center frequency is 2.1GHz.The antenna array is composed of 10 identical sub-modules.Through special structure design,it not only overcomes the shortcomings of the conventional microstrip antenna,but also has the characteristics of low profile,light weight and easy to fabricate.The antenna array achieved a relative bandwidth of 51.2%(1.52-2.57GHz,VSWR<2)and the gain is greater than 29d B in the whole bandwidth,furthermore,the maximum gain is up to 32.1d B,which is basically consistent with the simulation result.As a summary,the system works stably at a peak power of 140MW and it is able to meet the needs of wideband high power microwave radiation.3.Design and experiment of a wideband high power microwave double-layer radial line power dividerThrough theoretical analysis and simulation,the proposed 60 ports double-layer radial line power divider realizes well transmission character of microwave signals from1.64GHz to 3.6GHz,solving the problem of narrowband of traditional radial line feeding system.In addition,the radial line waveguide is divided into two layers by a wavy disk structure,which not only further reduces the size,but also achieves the wideband impedance matching of the power divider.In simulation,the S₁₁ parameter reached-44 d B at 2.1GHz,and the power capacity is more than 200MW.Furthermore,cold tests and high power tests are carried out,its symmetry and coupling characteristics are verified,and it can meet the requirements of feeding the designed wideband antenna arrays.