《电磁场与电磁波》课程教学资源（文献资料）专业中英文词汇表

附录4专业中英文词汇表Ampere安培force安培力定律s circuital law安培环路定律AmperAntenna天线Antenna pattern天线方向图Antenna array天线阵Angle of incidence入射角Angle of reflection反射角Angle of refraction折射角Anisotropic各向异nas口径天线Aperture antennArray factor阵因子Array factor of uniform lineararray均匀直线阵的阵因子衰减常婴Attenuationonstantin parallel-platewaveguide平行波导板的衰减常数waveguide矩形波导板的衰减常数tterBeamwidth波瓣宽度Binominal array二项式阵Binomial antenna array二项式天线阵Biot-Savart"slaw毕奥-萨伐尔定律Bound charge束缚电荷Boundaryconditions边界条件Boundary-value problems边值间惠布儒斯特角wsBrillouin diagram布里渊图enna宽频带天线array边射天线阵Capacitance电容Capacitor电容器per unitlength单位长度电容capactances笛卡儿坐标系Cavityresonators谐振腔

附录4 专业中英文词汇表 A Ampere安培 Ampere’s law of force安培力定律 Ampere’s circuital law安培环路定律 Antenna 天线 Antenna pattern天线方向图 Antenna array天线阵 Angle of incidence入射角 Angle of reflection反射角 Angle of refraction折射角 Anisotropic各向异性 Aperture antennas 口径天线 Array factor阵因子 Array factor of uniform linear array均匀直线阵的阵因子 Attenuation constant衰减常数 Attenuation constant in parallel-plate waveguide平行波导板的衰减常数 Attenuation constant in rectangular waveguide矩形波导板的衰减常数 B Beamwidth波瓣宽度 Binominal array二项式阵 Binomial antenna array二项式天线阵 Biot-Savart’s law毕奥-萨伐尔定律 Bound charge束缚电荷 Boundary conditions边界条件 Boundary-value problems边值问题 Brewster angle布儒斯特角 Brillouin diagram布里渊图 Broadband antenna宽频带天线 Broadside antenna array边射天线阵 C Capacitance电容 Capacitor电容器 Capacitance per unit length单位长度电容 Cartesian coordinate systems笛卡儿坐标系 Cavity resonators谐振腔

Charge density电荷密度Characteristic impedance特性阻抗Characteristic value特征值Circulation环量Circular wwaveguide圆波导Circularly polarized wave圆极化波line同轴传输线Coersivefield intensity矫顽场强度ittivity复电容率ComplexConductance电导Conductivity电率Conduction current传导电流Conductance per unit length单位长度电导Conduction current density传导电流密度Convection current运流电流Convection current density运流电流密度Conservative field保守场Conservation of electric charge电荷的守恒性relations本构关系ConstitutiveCoulonb’s law库仑定律Critical angle临界角Cross product叉积Curie temperature居里温度Cur1旋度Current density电流密度Cutoff wavelength截止波长Cutoff frequency截止频率Cylindrical capacitor园柱形电容器Cyindrical cordinates圆柱坐标系Degenerative mode简并模Depthof penetration穿透深度Diamagnetism抗磁性Dielectrical介质Dielectric breakdow介质击穿Dielectric strength介质强度Differential form微分形式Dipole偶极子Dipoleantena振子天线Dipole moment偶极矩Directional pattern方向图Directive gain方向性增益Directive gain of Hertzian dipole赫兹偶极子的方向性增益

Charge density电荷密度 Characteristic impedance特性阻抗 Characteristic value特征值 Circulation环量 Circular waveguide圆波导 Circularly polarized wave圆极化波 Coaxial transmission line同轴传输线 Coersive field intensity矫顽场强度 Complex permittivity复电容率 Conductance电导 Conductivity电导率 Conduction current传导电流 Conductance per unit length单位长度电导 Conduction current density传导电流密度 Convection current运流电流 Convection current density运流电流密度 Conservative field保守场 Conservation of electric charge电荷的守恒性 Constitutive relations本构关系 Coulomb’s law库仑定律 Critical angle临界角 Cross product叉积 Curie temperature居里温度 Curl旋度 Current density电流密度 Cutoff wavelength截止波长 Cutoff frequency截止频率 Cylindrical capacitor园柱形电容器 Cylindrical coordinates圆柱坐标系 D Degenerative mode简并模 Depth of penetration穿透深度 Diamagnetism抗磁性 Dielectrical介质 Dielectric breakdown介质击穿 Dielectric strength介质强度 Differential form微分形式 Dipole偶极子 Dipole antenna振子天线 Dipole moment偶极矩 Directional pattern方向图 Directive gain方向性增益 Directive gain of Hertzian dipole赫兹偶极子的方向性增益

Directivity方向性系数Directivity of half-wave dipole半波振子的方向性系数Directiviture radiator口径辐射器的方向性系数Dirichlet problems狄里赫里问题Dispersion色散Displacement current位移电流Distributed parameters分布参数Distortionlesstransmission line无失真传输线Divergence散度Dot product点积Double-stub双短截线E-plane pattern E面方向图Effective area有效面积Eigenvalue本征值Elemental factor元因子Electric charge电荷Electrolytic current电解电流Electric dipole电偶极子Electricdipolemoment电偶极矩Electric displacement电位移Electricfieldintensity电场强度Electric flux density电通密度Electrichertzpotential电赫兹位Electric potential电位tank电解槽ElectrolyticElectromagnetism电磁学ield电磁场ElectElectromagneticforces电磁力induction电磁感应ElectromaElectromagnetic model电磁模型Electromagnetic power电磁功率Electromagnetic theory电磁理论Electrostatic energy静电能Electrostatic energy of continuous charge distribution连续电荷分布的静电能Electrostatic energy of discrete charge distribution离散电荷分布的静电能Electrostatic emsof fiequantities以场能表示的静电能Electrostatic forces静电力staticfield静态电磁场Electromagtromotiveforce电动势（简称emf）Electromotarrelecdipole电基本振子ElemeEllipticallypolarized wave植圆极化液Endfire array端射式天线阵

Directivity方向性系数 Directivity of half-wave dipole半波振子的方向性系数 Directivity of aperture radiator口径辐射器的方向性系数 Dirichlet problems狄里赫里问题 Dispersion色散 Displacement current位移电流 Distributed parameters分布参数 Distortionless transmission line无失真传输线 Divergence散度 Dot product点积 Double-stub双短截线 E E-plane pattern E面方向图 Effective area有效面积 Eigenvalue本征值 Elemental factor元因子 Electric charge电荷 Electrolytic current电解电流 Electric dipole电偶极子 Electric dipole moment电偶极矩 Electric displacement电位移 Electric field intensity电场强度 Electric flux density电通密度 Electric hertz potential电赫兹位 Electric potential电位 Electrolytic tank电解槽 Electromagnetism电磁学 Electromagnetic field电磁场 Electromagnetic forces电磁力 Electromagnetic induction电磁感应 Electromagnetic model电磁模型 Electromagnetic power电磁功率 Electromagnetic theory电磁理论 Electrostatic energy静电能 Electrostatic energy of continuous charge distribution连续电荷分布的静电能 Electrostatic energy of discrete charge distribution离散电荷分布的静电能 Electrostatic energy in terms of field quantities以场能表示的静电能 Electrostatic forces静电力 Electromagnetostatic field静态电磁场 Electromotance or electromotive force电动势（简称emf） Elemental electric dipole电基本振子 Elliptically polarized wave椭圆极化波 Endfire array端射式天线阵

Energy density能量密度Endfire antenna array端射天线阵Equation of conductance连续性方程Equiangular spiral antenna等角螺旋天线Equipotential lines等位线surfaces等位面Equipotentiaon等效的磁化电流密度Evanescent mode迅衰模nce外电感xterFar-zone field远区场Far-zone fields of electric dipole电偶极子的远区场Far-zone fields of magnetic dipole磁偶极子的远区场Farad法拉（电容的单位）induction法拉第电磁感应定律Faraday s law of eleFerrites铁氧体Ferromagnetism铁磁体Flow source流量源Flux lines通量线Forces力Free space自由空间Frequency-independent antenna非频变天线Frequency-scanning antenna array频率扫描天线险Fresnel's equation非涅尔方程Friis transmission formula佛里伊斯传输公式Fundamental Units基本单位Gauss's law高斯定建Gradient梯度Groupvelocity群速Guided electromagnetic wave导行电磁波H-plane pattern H面方向图ndow半波长介质窗HalfielectrHalf-wave sections of Transmission line半波长传输线Harmonic function调和函数Helmholtz equation亥姆霍兹方程Henry亨利Hertz dipole赫兹偶极子Hertz potential赫兹位Homogeneous均匀ation齐次波动方程omogHysteresis沸后

Energy density能量密度 Endfire antenna array端射天线阵 Equation of conductance连续性方程 Equiangular spiral antenna等角螺旋天线 Equipotential lines等位线 Equipotential surfaces等位面 Equivalent current densities of magnetization等效的磁化电流密度 Evanescent mode迅衰模 External inductance外电感 F Far-zone field远区场 Far-zone fields of electric dipole电偶极子的远区场 Far-zone fields of magnetic dipole磁偶极子的远区场 Farad法拉（电容的单位） Faraday’s law of electromagnetic induction法拉第电磁感应定律 Ferrites铁氧体 Ferromagnetism铁磁体 Flow source流量源 Flux lines通量线 Forces力 Free space自由空间 Frequency-independent antenna非频变天线 Frequency-scanning antenna array频率扫描天线阵 Fresnel’s equation菲涅尔方程 Friis transmission formula佛里伊斯传输公式 Fundamental Units基本单位 G Gauss’s law高斯定律 Gradient梯度 Group velocity群速 Guided electromagnetic wave导行电磁波 H H-plane pattern H面方向图 Half-wave dielectric window半波长介质窗 Half-wave sections of Transmission line半波长传输线 Harmonic function调和函数 Helmholtz equation亥姆霍兹方程 Henry亨利 Hertz dipole赫兹偶极子 Hertz potential赫兹位 Homogeneous均匀 Homogeneous wave equation齐次波动方程 Hysteresis滞后

Ideal current source理想电流源[deal voltageource理想电压源Impedance阻抗ching阻抗匹配mpedImpedance matched of Transmission line传输线的阻抗匹配Impedai阻抗变换器Incidence入射Index of refraction折射率Inductance电感Inductance per unit length单位长度电感Input impedance输入阻抗Instantaneous power density瞬时功率密度Insulators绝缘体Integral form积分形式Internal impendence 内阻抗Internalinductance内电感units国际单位制InternationalstemIntrinsic impedance本征阻抗Intrinsic impedance of good conductor良导体的本征阻抗Intrinsicimpedanceof low-lossdielectric低损耗电介质的本征阻抗Inverse point反演点Irrotational field无旋场Isotropic各向同性Joule'slaw焦耳定律rrent law基尔霍夫电流定律Kirchhoff'Kirchhoff's voltage law基尔霍夫电压定律Laplace s equation拉普拉斯方程Laplacian拉普拉斯算符Legendre equation勒让德方程inction勒让德函数Legendre furLegendre polynomials勒让德多项式Lenz's law楞次定律Line charge density线电荷密度integral线积分ineiLineardipoleantenna线性振子天线Linearly polarizedwave线极化波Logarithmic spiral antenna对数螺旋天线Log-periodicantenna对数周期天线Longitudinal propagation纵向传播

I Ideal current source理想电流源 Ideal voltage source理想电压源 Impedance阻抗 Impedance matching阻抗匹配 Impedance matched of Transmission line传输线的阻抗匹配 Impedance transformer阻抗变换器 Incidence入射 Index of refraction折射率 Inductance电感 Inductance per unit length单位长度电感 Input impedance输入阻抗 Instantaneous power density瞬时功率密度 Insulators绝缘体 Integral form积分形式 Internal impendence 内阻抗 Internal inductance内电感 International system of units国际单位制 Intrinsic impedance本征阻抗 Intrinsic impedance of good conductor良导体的本征阻抗 Intrinsic impedance of low-loss dielectric低损耗电介质的本征阻抗 Inverse point反演点 Irrotational field无旋场 Isotropic各向同性 J Joule’s law焦耳定律 K Kirchhoff’s current law基尔霍夫电流定律 Kirchhoff’s voltage law基尔霍夫电压定律 L Laplace’s equation拉普拉斯方程 Laplacian拉普拉斯算符 Legendre equation勒让德方程 Legendre function勒让德函数 Legendre polynomials勒让德多项式 Lenz’s law楞次定律 Line charge density线电荷密度 Line integral线积分 Linear dipole antenna线性振子天线 Linearly polarized wave线极化波 Logarithmic spiral antenna对数螺旋天线 Log-periodic antenna对数周期天线 Longitudinal propagation纵向传播

Lorentz s force equation洛仑兹力方程Lorentzs gauge洛仑兹规范Loss angle损耗角Lumped parameter集总参数Magnetic charge 磁荷xlinkage磁通链fluxMagnetic circuits磁路ipole磁偶极子lagMagneticdipole moment磁偶极矩Magnetic domainsm/Magnetic energy 能Magnetic forces磁力Magnetic field intensity磁场强度MagneticfluxsMagnetic flux density磁通密度s of mutualinductance以磁感抗表示的磁力MagneticforceMagnetic force in terms of stored magnetic energy以磁储能表示的磁力Magnetic matals磁性材料Magnetic materialsof antifrrimagnetic抗铁磁性的磁性材料Magnetic materials of diamagnetic抗磁性的磁性材料Magnetic materials of ferromagnetic铁磁性的磁性材料Magnetic materials of paramagnetic顺磁性的磁性材料Magnetic potential磁位Magnetic susceptibility磁化率Magnetic torque磁转矩Magnetization curve磁化曲线ctor磁化强度失量MagnetizationMagnetomotance or magnetomotive force磁动势（简称mmf）波束（主瓣）Main beamMainmode主模nator谐振腔的主模Main mode focavlty res(Main modefparallel-platewaveguide平行板波导的主模angular waveguide矩形波导的主模Main mode fc1Matched condition forransmission line传输线的匹配条件Maxwell'sequations麦克斯韦方程组Medium媒质Method of images镜像法Method of images of pointcharge and conducting plane点电荷和导体板的镜像法Method of images of line charge and conducting cylinder线电荷和圆柱导体的镜像法Method of imagessof point charge and conducting sphere点电荷和导体球的镜像法Methodofseparationofvariables分离变量法Metric.coefficient度量系数

Lorentz’s force equation洛仑兹力方程 Lorentz’s gauge洛仑兹规范 Loss angle损耗角 Lumped parameter集总参数 M Magnetic charge 磁荷 magnetic flux linkage磁通链 Magnetic circuits磁路 Magnetic dipole磁偶极子 Magnetic dipole moment磁偶极矩 Magnetic domains磁畴 Magnetic energy磁能 Magnetic forces磁力 Magnetic field intensity磁场强度 Magnetic flux磁通 Magnetic flux density磁通密度 Magnetic force in terms of mutual inductance以磁感抗表示的磁力 Magnetic force in terms of stored magnetic energy以磁储能表示的磁力 Magnetic materials磁性材料 Magnetic materials of antiferrimagnetic抗铁磁性的磁性材料 Magnetic materials of diamagnetic抗磁性的磁性材料 Magnetic materials of ferromagnetic铁磁性的磁性材料 Magnetic materials of paramagnetic顺磁性的磁性材料 Magnetic potential磁位 Magnetic susceptibility磁化率 Magnetic torque磁转矩 Magnetization curve磁化曲线 Magnetization vector磁化强度矢量 Magnetomotance or magnetomotive force磁动势(简称mmf) Main beam主波束（主瓣） Main mode主模 Main mode for cavity resonator谐振腔的主模 Main mode for parallel-plate waveguide平行板波导的主模 Main mode for rectangular waveguide矩形波导的主模 Matched condition for Transmission line传输线的匹配条件 Maxwell’s equations麦克斯韦方程组 Medium媒质 Method of images镜像法 Method of images of point charge and conducting plane 点电荷和导体板的镜像法 Method of images of line charge and conducting cylinder线电荷和圆柱导体的镜像法 Method of images of point charge and conducting sphere点电荷和导体球的镜像法 Method of separation of variables分离变量法 Metric coefficient度量系数

mopole单极振子Mutualinductance互电感Near-zone field近区场Neper奈培（衰耗单位）Neumann formula纽受公式Nonhomogeneous wave equation非齐次波动方程Nonuniform plane wave非均勺平面波Normal component法向分量Ohm's law欧姆定律Open-circuited开路Orthogonal coordinate systems正交坐标系Parallel-platecapacitor平行板电容器Paramagnetism顺磁性Permeability磁导率Permittivity电容率Permittivity of free space自由空间的电容率Phase.constant相位常数Phase constant of good conductor良导体的相位常数-loss dielectric低损耗电介质的相位常数Phase constatoflowPhase constant of transmission line传输线的相位常数Phase velocity相速Phasors相量cidence入射面PlaneinPlane wave平面波ation泊松方程PoissorPolarization极化Polarizing angle极化角Polarization of planewave平面波的极化Polarization of a uniform planewave均匀平面波的极化Potential位Power density功率密度Power gain功率增益Poynting”stheorem坡印廷定理Principle of duality对偶原理Principleofpatternmltiplication方向图乘积定理Propagation constant传插播常数Quantities量Qualityfactor品质因素（Q）Quarter-wave transformer四分之一波长变换器

Monopole单极振子 Mutual inductance互电感 N Near-zone field近区场 Neper奈培（衰耗单位） Neumann formula纽曼公式 Nonhomogeneous wave equation非齐次波动方程 Nonuniform plane wave非均匀平面波 Normal component法向分量 O Ohm’s law欧姆定律 Open-circuited开路 Orthogonal coordinate systems正交坐标系 P Parallel-plate capacitor平行板电容器 Paramagnetism顺磁性 Permeability磁导率 Permittivity电容率 Permittivity of free space自由空间的电容率 Phase constant相位常数 Phase constant of good conductor良导体的相位常数 Phase constant of low-loss dielectric低损耗电介质的相位常数 Phase constant of transmission line传输线的相位常数 Phase velocity相速 Phasors相量 Plane of incidence入射面 Plane wave平面波 Poisson’s equation泊松方程 Polarization极化 Polarizing angle极化角 Polarization of plane wave平面波的极化 Polarization of a uniform plane wave均匀平面波的极化 Potential位 Power density功率密度 Power gain功率增益 Poynting’s theorem坡印廷定理 Principle of duality对偶原理 Principle of pattern multiplication方向图乘积定理 Propagation constant传播常数 Q Quantities量 Quality factor品质因素(Q) Quarter-wave transformer四分之一波长变换器

Quasi-static field准静态场Radiation efficiency辐射效率Radiation field辐射场Radiationntensity辐射强度Radiation pattern辐射方向图辐射电阻Radofhalf-wavedipole半波偶极子的辐射电阻RadiationRadiaipole赫兹偶极子的辐射电阻Radiation resistance ove monopole四分之一波长单极振子的辐射电阻fquarter-wayReceivin接收天线Receiving cross section接收截面ty relation互易关系ReciprocitRectangular矩形Reflection反射Reflection coefficient反射系数平面分界面上的反射系数Reflectiefficientsplalion line传输线终端的反射系数Reflection coefficient of terminated tRefraction折射Relative permittivity相对电容率Relaxation time驰豫时间Reluctance磁阻sidualfluxdensity剩余磁通密度RemanentdensitResistance电阻Resistance per unit length单位长度电阻Resistivity电阻率Retarded potential滞后位Saturation饱和material磁性材料的饱和batulScalar标量ential标量电位Scalarelectricpotential标量磁位calarmagnet标量积Scalartriple product标量三重积Scattering cross section散射截面Self- Inductance自感S半导体SemicorSeries connection of Capacitor电容器的审联Short-circuited短路SI system国际单位制Sidelobes旁瓣Single-stub单短截线

Quasi-static field准静态场 R Radiation efficiency辐射效率 Radiation field辐射场 Radiation intensity辐射强度 Radiation pattern辐射方向图 Radiation resistance辐射电阻 Radiation resistance of half-wave dipole半波偶极子的辐射电阻 Radiation resistance of hertzian dipole赫兹偶极子的辐射电阻 Radiation resistance of quarter-wave monopole四分之一波长单极振子的辐射电阻 Receiving antenna接收天线 Receiving cross section接收截面 Reciprocity relation互易关系 Rectangular矩形 Reflection反射 Reflection coefficient反射系数 Reflection coefficient at plane interface在平面分界面上的反射系数 Reflection coefficient of terminated transmission line传输线终端的反射系数 Refraction折射 Relative permittivity相对电容率 Relaxation time驰豫时间 Reluctance磁阻 Remanent flux density or residual flux density剩余磁通密度 Resistance电阻 Resistance per unit length单位长度电阻 Resistivity电阻率 Retarded potential滞后位 S Saturation饱和 Saturation of magnetic material磁性材料的饱和 Scalar标量 Scalar electric potential标量电位 Scalar magnetic potential标量磁位 Scalar product标量积 Scalar triple product标量三重积 Scattering cross section散射截面 Self- Inductance自感 Semiconductors半导体 Series connection of Capacitor电容器的串联 Short-circuited短路 SI system国际单位制 Sidelobes旁瓣 Single-stub单短截线

lart史密特圆图SmitiSnell'slaw ofreflection斯涅耳反射定理Snell'stion斯涅耳折射定律Solenoidal field管形场Source源Source-free无源Spherical capacitor球形电容器Spherical coordinates球坐标系Standingwave驻波Standing-wave ratio驻波比theorem斯托克斯定理StokesStriplines带状线Stub tuner短截线调谐器Surface charge density面电荷密度sity面电流密度SurtSurface impedance表面阻抗Surface integral面积分Surface wave表面波Tangential component切向分量Tesla特斯拉Time-averdensity时间平均功率密度erageTime-harmonic时谐Time-harmonic electromagnetism时谐电磁学Time-harmonic electromagnetic field时谐电磁场fields时谐场Torgue转矩Total reflection全反射Transformer变压器f变压器电动势Transmission coefficient传输系数Transmission line传输线Transmission-line equations传输线方程组ic(TEM）wave横电磁波TransTransverse electric(TE)wave横电波ansverse magnetic(TM)wave横磁波avelingwave行波enna行波天线Triple product三重积Tuners调谐器Two-element antenna array两元天线阵Two-wiretransmission line双线传输线ansversedistribution横向分布

Smith chart史密特圆图 Snell’s law of reflection斯涅耳反射定理 Snell’s law of refraction斯涅耳折射定律 Solenoidal field管形场 Source源 Source-free无源 Spherical capacitor球形电容器 Spherical coordinates球坐标系 Standing wave驻波 Standing-wave ratio驻波比 Stokes’s theorem斯托克斯定理 Striplines带状线 Stub tuner短截线调谐器 Surface charge density面电荷密度 Surface current density面电流密度 Surface impedance表面阻抗 Surface integral面积分 Surface wave表面波 T Tangential component切向分量 Tesla特斯拉 Time-average power density时间平均功率密度 Time-harmonic时谐 Time-harmonic electromagnetism时谐电磁学 Time-harmonic electromagnetic field时谐电磁场 Time-harmonic fields时谐场 Torgue转矩 Total reflection全反射 Transformer变压器 Transformer emf变压器电动势 Transmission coefficient传输系数 Transmission line传输线 Transmission-line equations传输线方程组 Transverse electromagnetic(TEM) wave横电磁波 Transverse electric(TE) wave横电波 Transverse magnetic(TM) wave横磁波 Traveling wave行波 Traveling-wave Antenna行波天线 Triple product三重积 Tuners调谐器  Two-element antenna array两元天线阵 Two-wire transmission line双线传输线 Transverse distribution横向分布

ray均匀直线天线阵nifore均匀平面酒uniformplanigueUnits单信quantities导出量单位位4tants通用常数Vector失量失量加法和减法Vector identities失量恒等式Vectorproduct量积Vector potential矢量位Velocity速度Velocityofwave propagation波的传插播速度ualdisplacement虑位移lirtiVolume charge density体电荷密度ty体电流密度VoluVolume integral体积分Vortexsource旋涡源Waveequation波动方程Wave impedance波阻抗Wavefront波前Waveguide波导Wavelength波长Wavenumber波数aantenna八木天线Yagi-Uo

U Uniform linear antenna array均匀直线天线阵 uniform plane wave均匀平面波 Unigueness theorem唯一性定理 Units单位 Units of derived quantities导出量单位 Unit vector单位矢量 Universal constants通用常数 V Vector矢量 Vector addition and subtraction矢量加法和减法 Vector identities矢量恒等式 Vector product矢量积 Vector potential矢量位 Velocity速度 Velocity of wave propagation波的传播速度 Virtual displacement虚位移 Volume charge density体电荷密度 Volume current density体电流密度 Volume integral体积分 Vortex source旋涡源 W Wave equation波动方程 Wave impedance波阻抗 Wavefront波前 Waveguide波导 Wavelength波长 Wavenumber波数 Y Yagi-Uda antenna八木天线