Some Key Techniques For Stealth UAV

From the theoretical analysis and practical application, the key issues of radar crosssection reduction of the UAV are detailedly studied. This dissertation is mainly involved in ofthe basic models scattering computation, the scattering analysis of the electric large modelsfor UAV, the testing of scattering targets, two-dimensional imaging models and the stealthmaterial design and using for the UAV. The analysis conclusion and results are identical facetesting results. By using the synthesis method for the UAV radar cross section reduction, itcan reduce6dB.The main contribution the dissertation can be summarized as follows:1. According to our experience in engineering applications, the electromagnetic scatteringtheory and the computing methods of calculation are discussed, which include numericalmethods (the method of moments (MOM) and the finite difference time domain (FDTD)algorithm), high-frequency algorithms such as physical optics (PO). According to ourpractices, a hybrid high-frequency algorithm (PO+IMEC) for rapid prediction estimates isprovided. In this dissertion, the real testing is finished for various scattering methods. Theadvantages and disadvantages of various algorithms for the same simulation targets aresummarized and analyzed. By Using the high-frequency hybrid algorithm the RCS predictionof the convex and concave bodies is discussed. It will become the fundation for the rapidcalculation of the UAV.2. From the scattering source and the scattering theory of the UAV, body parts of theUAV, such as the wing leading edge and the wing leading edge wedge structure, coated coverwing leading edge wedge andwing airfoil structure design, are analyzed. The process ofsimulation caculation for UAV is discussed. Finally, two different types of whole planemodels are simulated.3. The far-field test conditions, step-scan test method and the measurement data of timedomain and frequency domain noise cancellation processing are discussed. We focused on thelow frequency measurement techniques and measurement of all polarization information andprocessing technology. In order to improve the measurement data of the chamber and the usemade of information, the turntable laboratory imaging theory are discussed and analyzed. Inour anechoic chamber, two-dimensional imaging of the relevant algorithms and processes arefinished for two UAV targets. By imaging of the target will be converted intoone-dimensional scattering from two-dimensional image information. It can improve ourunderstanding of the scattering target and help to further improve the target shapingoptimization. 4. From the absorbing mechanism of the absorbing function materials, the application ofexisting conditions and absorbing materials on the principle of electromagnetic waveabsorption are discussed. Nano-thin metal films under the transmission effect ofelectromagnetic waves are presented. A thin metal film with the structural compositeabsorbing function materials is designed. Resonance (interference) absorbing principle ofmonolayer and multi-layer (double layer) are analyzed and tested. Finally, three patterns arecompared. The absorbing rate of three patterns is10dB. By using the synthesis reductionmethods, the numerical value reduction results of UAV achieve6dB.