射頻知識講座频 础 识讲
浙江三维通信 开发部
电信和广播电视的工作频带分配
波长的定义
λ = λ0 =
C 3 × 10 8 ( m / sec) 30 cm = F F ( c / sec) F GHz
λ (G ) =
λ 0 ε eff
εeff
= 30 cm F
GHz
ε eff
RF通信系统
频 线
, 线
对
RF
10 ~ 15 级
比值的对数尺度表示-dB数
为KW (103W )级 pW (10 12 W ),
数 dB = 10 log(
Pa ) or Pb
Pa = 10 10 Pb
dB
压
Va Va 数 dB = 20 log( ) or = 10 20 Vb Vb
dB
绝对功率电平的对数尺度表示-dB数
PmW = 10
dBm 10
,
PW = 10
103
dBw 10
.
基本电路中的电流电压关系
Zr = R + j 0 =
V i
ZL = 0 + jXL =
V i
ZC = 0 jXC =
V i
无载Q值和有载Q值的定义
储
Q(
载)
=
Q(
载)
=
储
归一化
RF元件的复数串联阻抗
X S = X L = 2πF Hz L H = 2πF GHz L nH
XS = XC =
1 159 = 2πF Hz C F F GHz C pF
ZS = RS ± jXS
Q= XS RS
RF元件的复数并联导纳
BP = BC = 2πFHzCf = 0.00628 FGHzCpF
BP = BL =
1 0 .159 = 2π F Hz L H F GHz L nH
YP = GP ± jBP
Q = BP GP 1 RP = XP = 1 XP RP
串联谐振和并联谐……
