电子科技大学：《无线系统中的微波与射频 Microwave and RF Design in Wireless Systems》课程教学资源（课件讲稿）ch04 Antennas and Propagation for Wireless System

●●● ●●●● ●●●●● ●●●● ●●●●0 ●●●0 ●●●● ●● The poynting vector for electromagnetic field: 电磁场的坡印廷矢量 §=ExH'W/m2 The time-average poynting vector 平均坡印廷矢量 Sww-Re(S}Rexi的wm 11

The poynting vector for electromagnetic field: * 2 S=E H W/m     The time-average poynting vector : 平均坡印廷矢量    * 2 avg 1 1 S = Re S = Re E H W/m 2 2      11 电磁场的坡印廷矢量

●●● ●●●● ●●●●G 2.Far-zone field distance远区场距离 ●●●● ●●●●0 ●●●0 ●●●● ● 2D2 R= △Φ=Π/8=22.50 见 D=300mm,入=8mm,R=22.5m For electically small (kD<1)ant.R=2 针对电小天线 EXAMPLE 4.1,page 114. 12

2. Far-zone field distance 远区场距离 For electically small (kD<1) ant. R f  2  D=300mm, =8mm, R f=22.5m △Ф=Π/8=22.5 o  2 2 D R f  EXAMPLE 4.1, page 114. 12 针对电小天线

●●● ●●●● ●●●●● 3.Radiation Intensity(辐射强度)： ●●●● ●●●● ●●●● Giving the variation in radiated power versus position around the antenna,also means the power in per unit solid angle.表示天线周围辐射功率随 指向的变化，即单位立体角内的功率。 (a)=7=r5F2Re(E万xH+,xH可列 [e+]F2[Ef+]w） =习 The total radiated Power: sin aa=Ia,小nuu4 13

3．Radiation Intensity（辐射强度）： Giving the variation in radiated power versus position around the antenna, also means the power in per unit solid angle. 表示天线周围辐射功率随 指向的变化，即单位立体角内的功率。 The total radiated Power:               P S rr d d U d d rad avg ˆ sin , sin 2 0 0 2 2     0 0            2 2 2 2 2 2 2 0 0 , Re 4 2 1 ( ) 2 2 avg P r U rS E H E H r E E F FW                                   13

●●● ●●●● 4.Radiation Patterns ●●●●● ●●●0 ●●●●0 ●●●● ●●●● 10gU(0,φp) ●● Main 个3dB beam sidelobe ldE,I dE. 900 Pencil beam Omnidirectional antenna Point-to-point satellite link Broadcast or handheld cellular 点对点卫星链路 14 广播或手持电话

4．Radiation Patterns 10lg U  , Pencil beam Point-to-point satellite link 点对点卫星链路 Omnidirectional antenna Broadcast or handheld cellular 广播或手持电话 14

●●● ●●●● ●●●●● ●●●0 ●●●●0 Legend Phi(horn_0)(E)_0 Phi(horn_90)(E)_0 0.0 5.0 10.0 -15.0 号 20.0 25.0 -30.0 35.0 .40.0 -180.0-120.0-60.0 0.060.0 120.0180.0 Angle 15

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