# Maxim 300MHz至450MHz发送器到小环形天线的匹配网络

## 基本的匹配网络

C1和环路电感在所要求的频率表现为正电抗，所以，可考虑用两个电容和环路电感作为“L”匹配网络(并联C，串联L)，此网络将小环路电阻变换到125Ω。从左往右看，它是一个低通、由高到低的匹配网络。偏置电感L1对于匹配不是关键元件，但作为直流通路，为PA提供工作电流是必须的，并可用来抑制高次谐波。

 At 315MHz At 433.92MHz C1= 2.82pf C1 = 1.47pf C2= 63pf C2 = 43pf L1= 36nH L1 = 27nH

 At 315MHz At 433.92MHz C1= 3.0pf C1 = 1.5pf C2= 33pf C2 = 27pf L1= 27nH L1 = 20nH

 At 315MHz At 433.92MHz C1= 3.3pf C1 = 1.65pf (2pf x 3.3pf in series) C2= 22pf C2 = 15pf L1= 27nH L2 = 20nH

## 具有高载波谐波抑制的匹配网络

 At 315MHz At 433.92MHz C1 = 3.0pf C1 = 1.5pf C2 = 33pf C2 = 30pf C3 = 12pf C3 = 8.2pf L1 = 51nH L1 = 33nH L2 = 47nH L2 = 33nH

 For 315MHz For 433.92MHz C1 = 3.3pf C1 = 1.65pf C2 = 22pf C2 = 18pf C3 = 12pf C3 = 8.2pf L1 = 51nH L1 = 33nH L2 = 47nH L2 = 33nH

## 总结和结论

1 Balanis, C, Antenna Theory, Analysis, and Design, Harper and Row, NY, 1982
2 Stutzman, W.A., G.A. Thiele, Antenna Theory and Design, Wiley, NY, 1981
3 Dacus, F., Van Niekerk, J., and Bible, S., "Introducing Loop Antennas for Short-Range Radios", Microwaves & RF, July 2002, pp. 80-88.