西安电子科技大学射频微波电路实验

R
=
ห้องสมุดไป่ตู้
RH Q2 +
1
,
X P2
=
RL Q
, XS2 = Q⋅R
图 2-4(a) Π型匹配电路
Q1 =
RS − 1 R
,
X P1
=
RS Q1
, X S1 = Q1 ⋅ R
L= X , C= 1
2πfC
2πfC ⋅ X
Matching Network Design5
设计一个工作中心频率400MHz，频宽40MHz的50-75Ω之T型阻抗匹配 器。（Rs = 50Ω ， RL = 75Ω）
Pout
RL
RL
QL = RL / XL
QS = QL =
RL −1 RS
X S = QS ⋅ RS
,
XL
=
RL QL
RS
XL
Vs
XS
RS
RL
圖 2-2(b) L型匹配电路 （ Rs > RL ）
Pout
RL
QS = QL =
RS −1 RL
XS
=
RS QS
, X L = QL ⋅ RL
Matching Network Design2
b2
b2
S参数 b1 = S11 a1 + S12 a 2
b2 = S 21 a1 + S 22 a 2
IRL = 20 log S11 Gain / Loss = 20 log S 21 Isolation = 20 log S12 ORL = 20 log S 22
Matching Theory1
TEM
TE
TM
9
传输线理论2
Equivalent Circuit of a transmission line:
RL
G
C
R, L, G, C: for unit length
Propagation constant（ γ） and characteristic impedance（Zo）:
dV = − ( R + jωL ) I Λ (1) dI = − (G + jωC )V Λ (2)
j
complex Γ plane
|Γ|=1
-1
1
-j 14
Smith Chart3
1.05
x=0.5
|Γ|=1
Smith Chart
x=1
Γr i( 0, θ )
+jx Γr i( 0.5, θ )
Γr i( 1, θ )
Γr i( 2, θ )
Γx i( 2, θ )
Γx i( 1, θ )
Γx i( 0.5, θ )
,
CS
=
1 2πfC ⋅
XL
图2-2(f) Lp-Cs高通式L型匹配电路
Matching Network Design3
RS
XS1
Pout
XS2
Rsmall = MIN( RS，RL )
Vs
RS
XP
R
XP2
1
RL
RL
R = Rsmall ⋅ (Q2 + 1)
, X S1 = Q ⋅ RS
,
X P1
r=0 Γx i( 0.5, θ )
Γx i( 1, θ )
Γx i( 2, θ )
Γ r( 0.1, θ )
Γ r( 0.5, θ )
- jx
|Γ|=0.5
|Γ|=0.1
r=0.5
r=1
r=2
x=2 r=∞
x=-0.5
1.05
x=-2
x=-1 1.05 Γr r( 0, θ ) , Γr r( 0.5, θ ) , Γr r( 1, θ ) , Γr r( 2, θ ) , Γx r( 2, θ ) , Γx r( 1, θ ) , Γx r( 0.5, θ ) , Γx r( 0.5, θ ) , Γx r( 1, θ ) , Γx r( 2, θ ) , Γ i( 0.1, θ ) , Γ i( 0.5, θ ) 1.05
X P1
=
0.79 pF
LS 2
=
X S1 2πf C
= 243nH
,
CP2
=
1 2πf C ⋅ X P2
= 0.64 pF
Attenuator(Pad)1
RS
RS2
Z1
RS
Z2
Z1 1
Z2
Rp
Rp1
Rp2
(a)
(b) p
(a) 「T型」功率衰减器；(b) 「Π型」功率衰减器
T-type Attn Rs Rp 3dB 9 433 6dB 17 67 10dB 26 35 15dB 35 18 20dB 41 10
90.371
0.440
1.92
10
10
90
2.0
0.3333
9.54
11.11
88.89
0.511
infinite
1
0
100
0
11
传输线理论4
常见传输线结构图
同轴线（coaxial cable） 微带线（microstrip） 带线（stripline） 平面波导（coplanar waveguide） 狭缝传输线（slot line）
Frequency
Impedance
Analyzer
Scalar / Vector
Impedance
Network Analyzer
Impedance Transformers Matching Networks Antenna
Spectrum Analyzer
Power
Power Meter
Attenuators ( PADs) Power Splitters Couplers
+jx
Γi Γ = Z L − Z o = r + jx − 1
Z L + Z o r + jx + 1
|Γ|
∠θ
r
Γr
z = r + jx = Z L = 1 + Γ Zo 1− Γ
-jx
13
Smith Chart2
Constant Re[ZL] circles
Constant Im[ZL] circles
dz
dz
from (1), (2), d 2V = ( R + jωL )(G + jωC )V = γ 2V dz 2
γ = ± ( R + jωL )(G + jωC ) , Z o = V / I = ( R + jωL )/(G + jωC )
10
传输线特性3
常用反射损耗 （RL）& 电压驻波比 （VSWR）对照表
射频电路实验
西安电子科技大学 电工电子实验教学中心
1
TOPIC 1
系统简介
2
射频前端收发机
Up-Mixer
Tx ANT PA
IF BPF IF AMP
Base Processor Unit (BPU)
PLL
VCO
IF AMP IF BPF
RF BPF PreAMP
Coupler
PAD
Gain Controller
99.773 99.174
0.010 0.036
1.22
20
1.3
0.1304
17.70
0.1 1.700
99.9 98.300
0.074
1.4
0.1667
15.56
2.779
97.221
0.122
1.43
15
1.5
0.2000
13.98
4.000
96.000
0.177
1.9
0.3103
10.16
9.629
•S11/S21测量功能
•功率测量功能 •频率测量功能 •PC连线功能 •18个电路模组
电路测量
RF 2000
射频微波电路导论
MOTECH
设计方法 MathCAD®
•电路设计公式 •*.mcd files •TRL •CAD-MsANT •RFGuide •WinSmith
•布线软件 •教学课程
MPIToSw刻er板P机CB
Smith Chart4 +jx
r =0 g= ∞
-jx
-jb
r =∞ g=0
+jb
Smith Chart5
Zs
ZL
Zo=75
Smith Chart6
Zo=50
Zs
ZL
Network Parameters for 2-port Network
I1 V1
2-Port Network
I2 V2
a1
VSWR
1.0
|Γ|
0.0000
Return Loss(dB)
infinite
Reflection Power(%)
0.000
Transmission Transmission
Power(%)
Loss(dB)
100.00
0.000
1.1
0.0476
26.45
1.2
0.0909
20.83
0.227 0.826
Power Splitter
PAD
RF BPF
LNA
Rx ANT
Down-Mixer
3
射频铁三角
Frequency Counter
Filters ( LPF, BPF, …) Oscillators
Voltage-controlled Oscillator(VCO)
Freq. Doublers / Multipliers/ Dividers Mixers ( Frequency Converter)
R = Rsmall ⋅ (Q2 + 1) = 5050
X P1
=
R Q
=
505
, X S1 = Q ⋅ RS = 500,
Q2 =
R − 1 = 8.145 RL
X S2 = Q2 ⋅ RL = 610.8
,
X P2
=R Q2
= 620
LS1
=
X S1 2πf C
= 198.9nH
,
C P1
=
1 2πfC ⋅
微带线（suspended microstrip）
方形波导（rectangular waveguide） 圆波导（cylindrical waveguide）
翼片波导（fin line） 介质波导（dielectric waveguide） 光纤（optical fiber)
12
Smith Chart1
Zs Vg
2-Port Network
a2
ZL
H参数 V1 = h11 I 1 + h12V 2 I 2 = h21 I 1 + h22V 2
Y参数 I 1 = y11V1 + y12V 2 I 2 = y 21V1 + y 22V 2
Z参数 V1 = z11 I 1 + z12 I 2 V 2 = z 21 I 1 + z 22 I 2
图(b)：输出功率与阻抗比例关系图
Matching Theory2
Zs
Pout
Vs
ZS ZL
ZL
广义「阻抗匹配」关系图 当ZL = ZS*，即是「匹配」( Matched )
Matching Network Design1
QS=Xs / Rs
Rs
Vs RS
Xs XL
圖 2-2(a) L型匹配电路 （ Rs < RL ）
Pi-type Rp Rs 292 18 130 45 96 71 72 136 61 248
（a）「T 型同阻抗式」( Z1 = Z2 = Zo )
（b）「Π型同阻抗式」
Z1 = Z 2 = Zo ，
A
α = 1010 Rp = Zo 2 ⋅ α
α −1
α −1 Rs1 = Rs2 = Zo ⋅
α +1
倍频器
Topic 11
混频器
Topic 12
天线
Topic 13
射频发射机
Topic 14
射频接收机
7
TOPIC 2
教材内容简介
8
传输线理论1
confine E and H fields between signal line and ground
Poynting Factor P = E x H Guided modes of EM waves:
Rs Vs
Vout RL
图(a)：输入输出功率关系图
1
Pout
=
I2
⋅ RL
=
VS 2 (RS + RL )2
⋅ RL
RL = k ⋅ RS
Pin
=
VS 2 RS
⇒
Pout
=
k (1 + k )2
⋅ Pin
Output Power
0.75
Pout ( k ) 0.5
0.25
0 k
ratio of RL to Rs ( k = RL / Rs )
A
α = 1010 Rs = Zo α − 1
电路模拟
Serenade®
•电路设计举例 •AnSoft_SV
布线制板
6
十二设计方案
Topic 1
传输线理论
Topic 2
阻抗匹配
Topic 3
功率衰减器
Topic 4
功率分配器
Topic 5
耦合器
Topic 6
滤波器
Topic 7
放大器
Topic 8
振荡器
Topic 9
压控振荡器
Topic 10
LS
=
XS 2πfC
,
CP
=
1 2πfC ⋅
XL
图 2-2(c) Ls-Cp低通式L型匹配电路
CS
=
1 2πfC ⋅
XS
,
LP
=
XL 2πfC
图 2-2(d) Cs-Lp高通式L型匹配电路
CP
=
1 2πfC ⋅
XS
,
LS
=
XL 2πfC
图 2-2(e) Cp-Ls低通式L型匹配电路
LP
=
XS 2πfC
=
R Q
图 2-3(a) T型匹配电路
Q2 =
R −1 RL
,
X P2
=
R Q2
, X S2 = Q2 ⋅ RL
L= X
2π f C
, C= 1
2πfC ⋅ X
RS
Vs RS
Matching Network Design4
XS1 XP1
XS2
R
XP2
RL
Pout
RH = MAX( RS，RL )
RL
Amplifiers ( SSA, LNA, PA )
4
射频训练教学 五大要素
设计理论 教材规划
电路测量
测试设备
设计方法
设计工具
布线 制板
刻布板线机软件
模拟软件
电路模拟
5
五大要素 解决方案
•包含十二个设计单元
設計理論
•传输线理论 •匹配理论 •功率衰减器 •功率分配器 •定向耦合器 •滤波器
•放大器 •振荡器 •压控振荡器 •微带天线 •射频发射机 •射频接收机