基地台自由空間輻射安全距離

•假設發射功率輸出為
–Po=43dBm=13dBW=2,000mW=20W
•假設發射天線增益為
–G=14dBi=25.1times (@900MHz)
–G=17dBi=50.1times (@1,800MHz)
•假設天線斜視損失為
–A=0dB=1times (@bore-sight in horizontal plane)
–A=3dB=2times (@±32.5°off bore-sight in horizontal plane)
–A=10dB=10times (@±60°off bore-sight in horizontal plane)
–A=20dB=100times (@±120°off bore-sight in horizontal plane)
•自由空間條件
–發射體周圍、接收體周圍、及發射體至接收體有效路逕以空氣為介質，且均無遮蔽物、反射物、折射物、繞射物、散射物
•輻射遠場與輻射近場條件(反之為感應近場條件)
–R>l/2p=(3e8/900e6)/(2x3.14159)=0.0531m (@900MHz)
–R>l/2p=(3e8/1800e6)/(2x3.14159)=0.0265m (@1,800MHz)
•計算自由空間輻射遠場與輻射近場之安全距離為
–R=[(30xPoxG/A)^(1/2)]/E=[(30x20x25.1/1)^(1/2)]/41.2=2.98m (@900MHz and bore-sight)
–R=[(30xPoxG/A)^(1/2)]/E=[(30x20x25.1/2)^(1/2)]/41.2=2.11m (@900MHz and ±32.5°off bore-sight)
–R=[(30xPoxG/A)^(1/2)]/E=[(30x20x25.1/10)^(1/2)]/41.2=0.943m (@900MHz and ±60°off bore-sight)
–R=[(30xPoxG/A)^(1/2)]/E=[(30x20x25.1/100)^(1/2)]/41.2=0.298m (@900MHz and ±90°off bore-sight)
–R=[(30xPoxG/A)^(1/2)]/E=[(30x20x50.1/1)^(1/2)]/58.2=2.98m (@1,800MHz and bore-sight)
–R=[(30xPoxG/A)^(1/2)]/E=[(30x20x50.1/2)^(1/2)]/58.2=2.11m (@1,800MHz and ±32.5°off bore-sight)
–R=[(30xPoxG/A)^(1/2)]/E=[(30x20x50.1/10)^(1/2)]/58.2=0.943m (@1,800MHz and ±60°off bore-sight)
–R=[(30xPoxG/A)^(1/2)]/E=[(30x20x50.1/100)^(1/2)]/58.2=0.298m (@1,800MHz and ±90°off bore-sight)