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 GHzλ (G ) =λ 0 ε effεeff= 30 cm FGHzε effRF通信系统频 线, 线对RF10 ~ 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 PbPa = 10 10 PbdB压Va Va 数 dB = 20 log( ) or = 10 20 Vb VbdB绝对功率电平的对数尺度表示-dB数PmW = 10dBm 10,PW = 10103dBw 10.基本电路中的电流电压关系Zr = R + j 0 =V iZL = 0 + jXL =V iZC = 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 nHXS = XC =1 159 = 2πF Hz C F F GHz C pFZS = RS ± jXSQ= XS RSRF元件的复数并联导纳BP = BC = 2πFHzCf = 0.00628 FGHzCpFBP = BL =1 0 .159 = 2π F Hz L H F GHz L nHYP = GP ± jBPQ = BP GP 1 RP = XP = 1 XP RP串联谐振和并联谐……