摘要
To distinguish the dielectric surface breakdown from the atmospheric breakdown, one method for atmospheric breakdown experiment by loading dielectric focusing lens is proposed. The focusing characteristics of dielectric focusing lens are investigated for the microwave frequency on the order of 1.3GHz to 9.3GHz, the lens focal length on the order of 0.3m to 0.9m and the dielectric constant on the order of 0.3 to 0.9. Simulations show that higher frequency, shorter focal length, and fitter dielectric constant result in better focus effect that the rising and falling edges of electric field strength change faster near the focus which is closer to the theoretical value. A dielectric focusing lens for the S-band is optimally designed with the polytetrafluoroethylene of 0.32 m thickness, 0.6m diameter,and 0.4m focal length. The focus indicator of dielectric lens is measured and the atmospheric breakdown experiment is carried out. The experimental values of atmospheric breakdown are consistent with the theoretical values. The electric field strength with the lens at the focus is 5–6times greater than that without focusing lens. The image of atmospheric breakdown by the dielectric lens focusing method experiment is clearer than that by the direct radiation method.
To distinguish the dielectric surface breakdown from the atmospheric breakdown, one method for atmospheric breakdown experiment by loading dielectric focusing lens is proposed. The focusing characteristics of dielectric focusing lens are investigated for the microwave frequency on the order of 1.3GHz to 9.3GHz, the lens focal length on the order of 0.3m to 0.9m and the dielectric constant on the order of 0.3 to 0.9. Simulations show that higher frequency, shorter focal length, and fitter dielectric constant result in better focus effect that the rising and falling edges of electric field strength change faster near the focus which is closer to the theoretical value. A dielectric focusing lens for the S-band is optimally designed with the polytetrafluoroethylene of 0.32 m thickness, 0.6m diameter,and 0.4m focal length. The focus indicator of dielectric lens is measured and the atmospheric breakdown experiment is carried out. The experimental values of atmospheric breakdown are consistent with the theoretical values. The electric field strength with the lens at the focus is 5–6times greater than that without focusing lens. The image of atmospheric breakdown by the dielectric lens focusing method experiment is clearer than that by the direct radiation method.
引文
[1]J.Zhang,Z.X.Jin,J.H.Yang,et al.,“Recent advance in longpulse HPM sources with repetitive operation in S-,C-,and X-Bands”,IEEE Transactions on Plasma Science,Vol.39,No.6,pp.1438-1445,2011.
[2]Y.Hidaka,E.M.Choi,I.Mastovsky,et al.,“Imaging of atmospheric air breakdown caused by a high-power 110-GHz pulsed gaussian beam”,IEEE Transactions on Plasma Science,Vol.36,No.4,pp.936-937,2008.
[3]J.K.Cao,D.F.Zhou,Z.X.Niu,et al.,“Air breakdown by repetition-rate high power microwave pulse”,High Power Laser and Particle Beams,Vol.18,No.1,pp.115-118,2006.
[4]A.M.Cook,J.S.Hummelt,M.A.Shapiro,et al.,“Observation of plasma array dynamics in 110GHz millimeter-wave air breakdown”,Physics of Plasmas,Vol.18,No.10,pp.724,2011.
[5]D.T.Hou,W.Zou,D.F.Zhou,et al.,“Characteristic of highpower microwave propagating through lower ionosphere”,High Power Laser&Particle Beams,Vol.17,No.8,pp.1239-1242,2005.
[6]Guidelines on the Assessment of installations Against Electromagnetic radiation(EMR)Exposure Limits(Edition September 2000),Australian Communications Authority.
[7]Q.X.Liu,X.Q.Li,C.W.Yuan,et al.,“Theoretical analysis and numerical simulation of a high power helical array antenna fed from double-layer radial waveguide”,Acta Electronica Sinica,Vol.33,No.12,pp.2231-2234,2005.(in Chinese)
[8]D.J.Yu,X.P.Zhang,Z.X.Niu,et al.,“Near-field region propagation model of typical plane antenna for HPM”,International Conference on Electronic Measurement and Instruments,IEEE,pp.2-100-2-103,2007.
[9]J.B.Shao,H.Q.Xie,Z.H.Li,et al.,“Study of a Ku-Band backward wave oscillator characteristics with low magnetic field of Acta Electronica Sinica 0.3T”,Acta Electronica Sinica,Vol.44,No.9,pp.2057-2061,2016.(in Chinese)
[10]D.F.Zhou,D.J.Yu,J.H.Yang,et al.,“Theoretical and experimental investigation of air breakdown on single high power microwave based on the mixed-atmosphere propagation model”,Acta Physica Sinica,Vol.62,No.1,pp.709-712,2013.
[11]H.C.Kim and J.P.Verboncoeur,“Transition of window breakdown from vacuum multipactor discharge to RFplasma”,Physics of Plasmas,DOI:10.1063/1.2403782,2006.
[12]S.K.Nam,C.Lim and J.P.Verboncoeur,“Dielectric window breakdown in oxygen gas:Global model and particle-in-cell approach”,Physics of Plasmas,Vol.16,No.2,DOI:10.1063/1.3068746,2009.
[13]B.P.Song,W.W.Shen,H.B.Mu,et al.,“Measurements of secondary electron emission from dielectric window materials”,IEEE Transactions on Plasma Science,Vol.41,No.8,pp.2117-2122,2013.
[14]X.Hao,S.Qiu,Q.Hou,et al.,“Damage phenomena of dielectric window material under X-band high power microwave”,High Power Laser&Particle Beams,Vol.21,No.1,pp.97-102,2009.
[15]G.Zhao,E.Yan,C.Chen,et al.,“Analysis and experimental study on threshold of air breakdown by high power microwave”,High Power Laser&Particle Beams,Vol.25,No.S1,pp.111-114,2013.