(LNA)
RF
I1
V1
1.
RF
IF
I2
I1
Vn1
Vn2
I2
V2
V1
NOISELESS
TWO-PORT
NETWORK
(b)
V2
NOISY
TWO-PORT
NETWORK
(a)
(a)
(b)
Vn1
Vn2
In1
In2
2
5
6
=
I Y V Y V In
1
1
12 2
11 1
+
+
—
(
1a)
2
In1
In2
7
8
=
I Y V Y V I n
2
22 2
21 1
+
+
2
(
(
(
(
5)
6)
7)
8)
Vn1 Vn2
(
1b)
Vn1 Vn2
1b
1
2
=
=
+
+
+
+
V Z I Z I Vn
1
1
12 2
11 1
V Z I Z I Vn
2
22 2
21 1
2
Z
(
(
1
2
Vn1 Vn2
(I1 = I2 = 0)
(
3
4)
V
n1
=
V I
1 1
=
I
2
=
0
V
n2
=
V I
2 1
=
I
2
=
0
(
(
Vn1 Vn2
=
I V V
1
2
1
=
I V V
2
2
1
=
0
=
0
=
I
n1
=
I
n2
1b
2
I1
V1
In1
NOISELESS
TWO-PORT
NETWORK
In2
I2
V2
2.
In1
In2
1)
2)
3)
4)
12
(
3)
ABCD
9
10
3
−
V AV B I
1
2
=
+
(
2
+
)
Vn
=
−
I CV D I
1
2
+
(
2
+
)
In
9
10
Vn
In
I1
V1
3
In
Vn
In
Vn
1b
I2
V2
NOISELESS
TWO-PORT
NETWORK
(
(
9)
10)
I n
V n
In2
In1
n = −
V
2
I
n
Y
21
=
I
n
I
n
1
−
Y
11
Y
21
I
n
2
(
4)
Vn1 Vn2
Ys
I2
sc)
(I2
s)
F
= 2
I
I
SC
2
S
3.
(
1b
Z
−
+
I
n
)
=
V Z I
(
11 1
1
Vn
In
)
3
V n1 V n2
3
Vn
In
Vn
Ys
Is
I2
V2
In
NOISELESS
TWO-PORT
NETWORK
INPUT
PORT
+
Z I V Z I Z I
12 2
12 2
11 1
n
=
+
+
(
−
V Z I
11
n
)
n
(
11)
4.
2
(
(
17)
18)
(
F
(
19)
Isc
=
V Z I
(
21 1
2
−
+
I
n
)
Z I Z I Z I
22 2
22 2
21 1
=
+
−
)
n
Z I
21
(
1
2
11
=
1
V
n
12
−
V Z I
11
n
n
= −
V
n
2
Z I
21
n
13
14
Vn
In:
n=
V V
n
1
−
I
n2
Z
Z
11
21
= −
I
n
2
V
n
Z
21
(
(
(
(
12)
13)
14)
15)
16)
13
= −(
+
I
s
2
I
sc
20
20
Isc = -Is + In + VnYs
20
) −
2
2
+
I V Y
n
s
n
) =
2
+(
I
2
s
+
I V Y
n
s
n
(
I I V Y
s
s
+
n
n
)
(
(
(
(
20)
21)
22)
23)
)
2
(
I I V Y
s
n s
+
n
) = 0
2
I
sc
=
I
2
s
+(
+
I V Y
n
s
n
19
= +
1
F
(
)
2
+
I V Y
n
s
n
2
s
I
Vn
In
In
—
Vn
(Inu)
34
Vn
(Inc)
=
I
n
I
nu
+
I
nc
(
24)
Yc
Inc Vn
=
I
nc
Y V
c n
24
=
I
n
I
nu
+
Y V
c n
25
(
(
25)
26)
Yc
26
Vn*
InuVn
*= 0
(
27)
Gs
* =
I V
n n
Y V
c
2
n
26
= +
1
F
23
(
I
nu
+
(
Y
c
= *
V I
n n
2
V
n
F
Y Y V
n
)
s
+
2
s
c
I
)
2
(
(
(
(
(
(
28)
29)
30)
Gu
31)
32)
33)
+
1
kT G B
0
s
4=
I
2
s
Gs = Re [Ys]
Rn
V
2
n
4=
I
2
nu
4=
29
30
31
kT R B
0
n
kT G B
0
u
28
+
=
Y G jB
c
c
c
=
Y G jB
s
s
s
+
4
= +
1
F
kT G B G jB G jB
0
u
s
+
+
4
s
+
+
c
kT G B
0
s
2
4
c
kT R B
n
0
=
= +
1
G
u
G
s
+
R
n
G
s
[
(
G G
c
+
s
) +(
2
B B
c
+
s
]
)
2
(
34)
Ys
34
F
= −
B
c
B
s
F
Bs
= − = +
1
Bc
G
u
G
s
+
(
R
n
G
s
34
Gs
+
G G
c
s
(
(
35)
36)
)
2
(
+
G G
s
)
)
2
c
(
(
=
0
38)
39)
dF
= −
Bs
dG
s
Bc
= 0
(
37)
(
2
dF
= −
Bs
dG
s
Bc
= −
G
u
2
G
s
+
R
n
(
G G G
s
s
+
)−
c
G
2
s
=
G
s
G
+2
c
G
R
u
n
39
35 Gs Bs
)
(
Yopt = Gopt + jBopt
Y
opt
=
G
opt
+
jB
opt
=
+
G
2
c
G
R
u
n
−
jB
c
(
40)
36
F
min
=
F
=
Ys Yopt
= +
1
u
+
G
G
opt
3 9
G u / G o p t
Fmin
(
n
opt
R
G
G
)
2
+
G
c
opt
(
41)
4 1
R G
n
−
opt
42
=
(
G
2
opt
+
2
G G G
opt
c
+
) =
2
c
Fmin
n
R
G
opt
+
G
G
2
c
opt
(
R G
n
)
+
G
c
opt
(
42)
+
1 2
34
(
=
F F
−
min 2
+
c
n
R G G
) +
+
(
2
G G
s
c
)+
G
G
opt
−
B B
s
opt
u
s
)
+
2
(
43)
(
R
n
G
s
14
opt
=
g
opt
+
jb
opt
(
47)
LNA
(
50)
Smith
−
4
F F
r
n
min
+
1
Γ
opt
2
=
−
Γ
s
−(
1
Γ
opt
Γ
2
s
2
)
=
N
−
Γ
s
−(
1
Γ
opt
Γ
2
s
2
)
with N
=
−
4
F F
r
n
min
2
+
1
Γ
opt
2
Γ
opt
Γ Γ
s opt
Γ
2
s
+
)
2
1
−(
) =
2
Γ
s
Γ
s
2
−
Γ Γ
s opt
2
+
Γ
opt
2
)
Γ
s
2
=
N
+
Γ Γ −−
s opt
2
−(
N
1
+(
1
N
2
=
Γ
s
N
+(
1
N
) +
2
Γ
s
−
Γ
s
) +
−
Γ Γ
2
s opt
+(
1
N
Γ
opt
+(
1
N
2
) =
) −
Γ Γ
2
s opt
+(
N
1
2
Γ
opt
+(
1
N
2
) −
2
N
1
+(
N
1
)
2
2
)
N
Γ
opt
Γ
opt
+(
1
Γ
) =
opt
+(
1
N
−
1
N
+
2
2
2
2
Γ
opt
+(
1
)
N
N
+(
1
N
Γ
opt
2
) −
=
O
N
Γ
opt
+(
N
1
)
with N
= −
F F
4
r
n
min
2
+
1
Γ
opt
=
R
N
1
+(
N
1
)
2
N N
+
(
51)
−
1
2Γ
opt
(
52)
51
52
Smith
LNA
(SNR)
(
)
Yopt = Gopt + jBopt
Fmin
F
2
Γ
s
=
N
−
39
Gu
43 F
−
G G
s
) +
2
(
opt
−
B B
s
)
2
opt
(
44)
+
R
n
G
s
(
F
=
F F
min
44
Ys
=
F F
min
+
R
n
G
s
−
y
y
s
opt
2
=
+
rn
F
min Re (
al y
)
s
−
Y Y
s
opt
2
rn = Rn/Z0
:
=
y
s
=
Y
s
Y
0
G jB
s
s
+
Y
0
(
45)
ys = YsZ0
=
g
s
+
jb
s
(
46)
yopt
=
y
opt
Y
opt
Y
0
G
opt
=
jB
+
Y
0
ys
yopt
y
s
= −
1
+
1
Γ
s
Γ
s
← →
Γ
s
= −
1
+
1
y
y
s
s
=
y
opt
−
+
1
1
Γ
opt
Γ
opt
← →
Γ
opt
=
−
+
1
1
y
y
opt
opt
(
48)
ys
yopt
(
LNA
45)
LNA
Gopt
S
Γ
s
Γ
opt
−
Γ
opt
2
−(
1
=
F F
min
+
4
rn
+
1
Smith
2
)
2
Γ
s
(
49)
F (
49)
15
LNA (
)
MAX2656
)
LNA
LNA
(
Rollet
1 (K
(K)
)
LNA
(ΓL)
LNA
Γ
L
=
S
+
22
S
1
21
−
Γ
s
S
11
S
12
Γ
s
*,
(
53)
ΓS
(
LNA
MAX2656——
LNA (
5)
ΓL)
(IP3)
PCS
(14.5dB
VCC = 3V
1
3
RBIAS
L1 = 1.2nH
C2 = 1.5pF
Cb
4
BIAS
MAX2656
2
5
RF
C1 = 1.8nF
5. MAX2656 LNA
0V : HIGH GAIN
VCC : LOW GAIN
10kΩ
6
C3 = 3.6pF
RF OUTPUT
0.8dB
(
MAX2656
IP3
)
1.9dB
RBIAS
) MAX2655/
(RBIAS)
5
MAX2656 LNA
1960MHz
)
PCS
MAX2656
(RBIAS)
2dB
50Ω
(
715Ω 1960MHz
(Fmin = 1.79dB)
Γopt
Γ
opt
=
°
0 130 124 48
.
/
.
(
54)
RN = 43.2336Ω
1960MHz MAX2656 LNA
S
(
/
)
• S11 = 0.588/-118.67°
• S21 = 4.12/149.05°
• S12 = 0.03/-167.86°
• S22 = 0.275/-66.353°
(K = 2.684)
5
)
2dB
3dB 3.5dB
2dB
50Ω
ΓS = 0.3/150°
arc ΓSA (
arc BO (
C1
ΓS
L1
Smith
( 6)
(
2.5dB
)
)
arc Γ SA
0.3
50 x 0.3 = 15Ω
[2π x (1.96 x 109)] = 1.218nH
Z =
L1 = 15/ω = 15/(2πf) = 15/
1.2nH
arc BO
1/Y = Z =
50 /0.9 = 55.55Ω
C2 = 1/(55.55 x ω) = 1/
(55.55 x 2πf) = 1/[55.55 x 2π x (1.96 x 109)] = 1.46pF
0.9
1.5pF
16
6. Smith
MAX2656 PCS LNA
(
)
2dB
17
13dB
Constant
Gain Circle
ΓL = 0.236 / 70.5°
O
13.6dB Desired
Constant Gain
Circle
7. MAX2656 PCS LNA
2dB
18
C1
ΓS
LNA
5 LNA
Γ
L
=
S
+
22
S
1
21
−
Γ
s
S
11
S
12
Γ
s
=
*
°
0 236 70 5
.
.
/
(
55)
C3
MAX2656
50Ω
50Ω
7
ΓL
arc OΓL (
C3
arc OΓL
Z =
50 x 0.45 = 22.5Ω
C3 = 1/(22.5 x ω ) =
1 / (22.5 x 2πf ) = 1/ [22.5 x 2π x (1.96 x 109) ] =
3.608pF
3.6pF
)
0.45
1. Gonzalez, Guillermo; Microwave Transistor
Amplifiers, Analysis & Design ;
,
Prentice Hall, Upper Saddle River, New
Jersey 07458.
2. Bowick, Chris; RF Circuit Designs ; Howard
W. Sams & Co., Inc., ITT
19