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Tomomi Research Inc.
RF Power Amplifier Tutorial (1)
2016/07/20Seong-Hun Choe
Tomomi Research Inc.
Gain
Power Amplifier (PA)
Gain (G) Pin Pout
𝐺 [𝑑𝐵 ]=10 𝑙𝑜𝑔10 (電力比 )=10 𝑙𝑜𝑔10( 𝑃𝑜𝑢𝑡
𝑃 𝑖𝑛)
10 dB
-3dB
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Gain written as a voltage
Let R1 = R2
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Gain written as a Current
Let R1 = R2
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Gain Summary
ExpressionPower [dB]
Voltage [dB]Current [dB]
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Transitor Data Sheet2sC3356 (Renesas Electronics)
http://jp.rs-online.com/web/p/bipolar-transistors/7724980/
トランジスタの入力側（ Base)にインピーダンス整合回路を設けずに、 50Ohmの信号発生器から 1GHzの信号を入力すると、(0.26)^2*100 = 6.8%の電力の反射が起こることを意味
http://amplet.tokyo/tu/pdf/2sc3356.pdf
Tomomi Research Inc.
Transitor Data Sheet2sC3356 (Renesas Electronics)
http://jp.rs-online.com/web/p/bipolar-transistors/7724980/
トランジスタの出力側（ Collector)にインピーダンス整合回路を設けずに、 50Ohmの信号発生器から 1GHzの信号を入力すると、 (0.266)^2*100 = 7.1%の電力の反射が起こることを意味
http://amplet.tokyo/tu/pdf/2sc3356.pdf
Tomomi Research Inc.
Transitor Data Sheet2sC3356 (Renesas Electronics)
http://jp.rs-online.com/web/p/bipolar-transistors/7724980/
トランジスタに電源を供給し、インピーダンス整合回路を設けずに、 50Ohmの信号を入力すると、 10log(3.744)^2=11.5 dBの利得（ゲイン）があることを意味する。
http://amplet.tokyo/tu/pdf/2sc3356.pdf
Tomomi Research Inc.
Transitor Data Sheet2sC3356 (Renesas Electronics)
http://jp.rs-online.com/web/p/bipolar-transistors/7724980/
トランジスタの出力側（ Collector)にインピーダンス整合回路を設けずに 50Ohm系の信号発生器から 1GHzの信号を入力すると、 10Log(0.236)^2=-17.3dBが減衰してトランジスタの入力側 (Base)に出力されることを意味する。http://amplet.tokyo/tu/pdf/2sc3356.pdf
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dB( デシベル）： 物理量のレベルを表す単位。無次元量である。dBm : 電力を表す単位である。要は Watt に変換ができる単位。 dB と混同しないように注意。0 [dBm] = 1 [mW]
dBmと dB
Power [mW] Power [dBm]
1 mW 0dBm=
10 mW 10dBm=
100 mW 20dBm=
1W 30dBm=
10W 40dBm=
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dBm と GainPower Amplifier (PA)
Gain (G)= 25 [dB]
Pin= 1 mW Pout= ?
Pout[dBm] = Pin [dBm] + Gain [dB] = 0 [dBm] + 25 [dB] = 25 [dBm] = 10 ^ (25/10) = 316.22 [mW]
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dBm と Gain
Power [mW] Power [dBm]
1 mW 0dBm=
10 mW 10dBm=
100 mW 20dBm=
1W 30dBm=
10W 40dBm=
http://www.ebay.com/itm/182194447106?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
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この表でゲインを計算（次のページ）
http://www.ebay.com/itm/141841663164?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
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14 MHzinput
power [W]input power
[Vpp]output
power [W]output power
[Vpp] Gain at 14 MHz [Power]
Gain at 14 MHz[Voltage ]
0.5 14.2 9.7 60.4 12.88 12.57 1 20 18.5 83.2 12.67 12.38 2 28 33 110 12.17 11.88 3 35 46 128 11.86 11.26 4 40 54 141 11.30 10.94 5 45 60 148 10.79 10.34
5.3 46 64 151 10.82 10.32
7 MHzinput
power [W]input power
[Vpp]output
power [W]output power
[Vpp] Gain at 7MHz [Power]
Gain at 7 MHz [Voltage ]
0.1 6.3 1.66 26.6 12.20 12.51 0.5 14 27 104 17.32 17.42 1 20 55 146 17.40 17.27 2 28 93 196 16.67 16.90 3 35 106 208 15.48 15.48 4 40 112 213 14.47 14.53 5 45 114 214 13.58 13.54
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0 1 2 3 4 5 60
2
4
6
8
10
12
14
16
18
20
12.88 12.67 12.17 11.86 11.30 10.79 10.82 12.20
17.32 17.40 16.67 15.48
14.47 13.58
Gain at 7MHz [Power] Gain at 14 MHz [Power]
input power [W]
Gain
[dB]
0 1 2 3 4 5 60
20
40
60
80
100
120
9.718.5
33
4654
6064
1.66
27
55
93
106112 114
output power at 7MHz [W]
output power at 14 MHz [W]
input power [W]
Out
put p
ower
[W]
Input power vs. Output powerこれがまっすぐだと Linear Ampと呼ばれる Input powerによる Gainの変化。まあまあまっすぐ
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Efficiency definitions in RF Power Amplifier
Matching Network
Matching Network Load
Driver Pin
Pout
Pdc
+Vdc
L
Gain : Gp
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Collector Efficiency
𝜂𝑐𝑜𝑙𝑙𝑒𝑐𝑡𝑜𝑟=𝑃𝑜𝑢𝑡
𝑃𝑑𝑐
Bipolar transistors (BJTs)Po : the RF output powerPdc: the input power supplied by the DC supply to the collector(Pdc = Vdc*Idc)
Gain : Gp
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OVERALL Efficiency
𝜂𝑜𝑣𝑒𝑟𝑎𝑙𝑙=𝑃𝑜𝑢𝑡
𝑃 𝑖𝑛+𝑃𝑑𝑐
𝑃𝑜𝑢𝑡=𝐺𝑝𝑃 𝑖𝑛
𝜂𝑜𝑣𝑒𝑟𝑎𝑙𝑙=𝑃𝑜𝑢𝑡
𝑃𝑜𝑢𝑡
𝐺𝑝+𝑃
𝑑𝑐
Gain, P_out, P_dcだけで、効率を表す。Gain : Gp
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POWER ADDED efficiency
𝜂𝑃𝑜𝑤𝑒𝑟 𝑎𝑑𝑑𝑒𝑑=𝑃𝑜𝑢𝑡−𝑃 𝑖𝑛
𝑃𝑑𝑐
𝑃𝑜𝑢𝑡=𝐺𝑝𝑃 𝑖𝑛
Gain, P_out, P_dcだけで、効率を表す。
𝜂𝑃𝑜𝑤𝑒𝑟 𝑎𝑑𝑑𝑒𝑑=𝑃𝑜𝑢𝑡−
𝑃𝑜𝑢𝑡
𝐺𝑝
𝑃 𝑑𝑐
Gain : Gp
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Example100W
150W
Gain , Gp = 10
equation Value
Collector efficiency 66.7% = 100/150
Overall efficiency 62.5%=100/(100/10+150)
Power added efficiency 60%=(100-100/10)/150
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Power output Capability
Matching Network Load
Pout
Pdc
+Vdc
L
Gain : Gp Vc,pk
Ic,pk
Collectorからいくら電力が取り出せるかを表すパラメータThe output power produced when the device has a peak collector voltage of 1[V] and a peak collector current of 1 [A].
𝐶𝑃=𝑃𝑜𝑢𝑡
𝑁 𝐼𝐶 ,𝑝𝑘𝑉 𝑐 ,𝑝𝑘
Cp : power output capabilityPout : output power [W]N : number of transistors in parallel or push pull designIc,pk : the peak collector current[A]Vc,pk : the peak collector voltage [V]
Important for cost effective design
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ExampleA single ended class E circuit : Theoretical power output capability Cp, class E = 0.0981
The designed the peak collector voltage Vc,pk = 100 [V]The peak current will be
𝐶𝑃=𝑃𝑜𝑢𝑡
𝑁 𝐼𝐶 ,𝑝𝑘𝑉 𝑐 ,𝑝𝑘
𝐼𝐶 ,𝑝𝑘=𝑃𝑜𝑢𝑡
𝑁 𝐶𝑃,𝑉 𝑐 ,𝑝𝑘
10.19 [A] = 100 / (1 * 0.0981 * 100)
