背射天線 的英文怎麼說
中文拼音 [bēishètiānxiàn]
背射天線
英文
back fire antenna-
Topics include : planets, planet formation ; stars, the sun, " normal " stars, star formation ; stellar evolution, supernovae, compact objects ( white dwarfs, neutron stars, and black holes ), plusars, binary x - ray sources ; star clusters, globular and open clusters ; interstellar medium, gas, dust, magnetic fields, cosmic rays ; distance ladder ; galaxies, normal and active galaxies, jets ; gravitational lensing ; large scaling structure ; newtonian cosmology, dynamical expansion and thermal history of the universe ; cosmic microwave background radiation ; big - bang nucleosynthesis
課程的主題包含了：行星、行星形成；恆星、太陽、正常的恆星、恆星形成；恆星演化、超新星、緻密天體（白矮星、中子星及黑洞） 、波霎、雙x -射線源；星團、球狀及疏散星團；星際介質、氣體、塵埃、磁場、宇宙射線；距離階梯；星系、正常及活躍星系、噴流；重力透鏡；大尺度結構；牛頓宇宙學、宇宙的動力膨脹及溫度發展歷史；宇宙背景微波輻射；大霹靂核合成。A patch antenna with air holes in the substrate has been designed. the finite - difference time - domain ( fdtd ) method together with the perfectly matched layer ( pml ) boundary treatment has been used to study the performance of the antenna. it is shown that the surface waves are significiently suppressed, the frequency bandwidth is improved, the sidelobe levels are reduced and consequently the gain in the forward direction is improved by 14 db ( about 4 db higher than the value reported previously )
設計了一種基底鉆周期圓孔結構的電磁（光子）晶體貼片天線，用fdtd方法並結合pml吸收邊界條件對該天線進行了研究，結果表明本文所設計的基底鉆孔型電磁晶體貼片天線取得了多方面的性能改善，與普通天線相比，基底中的表面波受到很大抑制，天線的帶寬增加，遠場方向圖上天線的旁瓣和背瓣被明顯削弱，向前輻射的增益由原來的12db增加到26db ，增加了14db ，比文獻上報道的gonzalo等人的研究結果提高了4db 。This technique combines the edge - based finite - element method with physical optics ( po ) and physical theory of diffraction ( ptd ). the hybrid technique is applied to compute the scattering fields from the electrically large bodies with cracks and cavities on their surfaces. it is also used to analyze the scattering characteristics of microstrip antennas residing in a cavity mounted on metal objects with finite sizes
本文採用edge - basedfem為基本方法，結合物理光學法（ po ） 、物理繞射理論（ ptd ） 、邊界積分方程（ bi ） 、區域分解技術（ ddm ）和完全匹配層（ pml ）吸收邊界條件等求解方法構成的混合方法，對電磁散射和輻射問題進行了研究，主要包括以下內容：提出了一種edge - basedfem與物理光學方法和物理繞射理論相結合的混合方法? fem po - ptd方法，並將該混合方法應用於帶有腔體或槽縫的電大尺寸導體目標的電磁散射特性分析和位於有限導體目標上的背腔式微帶貼片天線的電磁散射特性分析。Scattering analysis of cavity - backed microstrip patch antenna based on finite - element method
基於有限元法的背腔微帶貼片天線的散射研究The radiation problems of microstrip antennas residing in a cavity are analyzed by the edge - based fem with perfectly matched layer ( pml ) absorbing boundary condition ( abc )
將edge七asedfem與完全匹配層吸收邊界條件相結合，分析了背腔式微帶天線和背腔式分形微帶天線的電磁輻射特性。A hybrid technique of fem with boundary integral ( bi ) technique is employed firstly for the evaluation of electromagnetic scattering by microstrip fractal patch antennas residing in a cavity. the calculated results show that the electromagnetic scattering of the microstrip fractal patch antennas residing in a cavity depends largely on the driven element rather than on the parasitic fractal elements
將edge一basedfem與邊界積分方程相結合，分析了背腔式分形微帶貼片天線的電磁散射特性，得出了分形微帶天線的電磁散射特性主要由分形微帶天線的激勵單元而不是由寄生單元決定的結論。Subsequently, the waves induced forces and their driven effects on currents are studied in detail. in the discussion of the effects of currents on waves, according to the wave radiation theory and the law of wave action conservation, the equivalence of none vorticity condition of the vector of wave number in constant wave field and fermat theory is testified. the dynamic and kinematics effects of background currents on waves are introduced concisely
在流對浪的作用討論中，依據波動的射線理論和由變分原理導出的波作用量守恆定律，闡明了穩定波場波數矢量的無旋條件與費馬原理的等價性，扼要討論了背景流場影響海浪的運動學效應和動力學效應，首次指出水位（包括天文潮位與風暴潮位）變化對海浪成長與消衰的影響，為流浪潮聯合數值模式的發展提供必要的理論依據。Over - the - horizon radar ’ s beam - frequency is high frequency band and its wavelength is so long that the annate ’ s characters are very complicated when applicated on the ship. the character of coupling between cells and the environment must be measured to compensate in the radar signal process step. the ship - based over - the - horizon radar uses cfa ( crossed field antenna ) as array antennas ’ cell
艦載超視距雷達使用高頻信號作為發射頻率，其波長較長，在艦船有限的空間內，陣列天線的陣元之間的耦合與陣元與背景之間耦合都十分嚴重，必須測量陣列天線通道的幅相一致性，作為雷達信號處理的補償參數。分享友人