Microwave Amplifier Design Preview

1
Microwave Amplifier Design Preview

• Design considerations
• Systematic procedure
• Transistor
• stability
• compromise between gain and noise
• Design IMN and OMN
• Testing with the software, (Puffetc)
• Biasing
• Electronic Workbench(Protel PCB Schematic)

2
Transistor

• MGF1402
• Reliable, HF Low Noise applications
• Higher electron mobility
• S-Parameters
• Noise Parameters

S21
a1
a2
S22
Two Port
S11
b2
b1
Output Port
Input Port
S12
3
TOOLS

• Transmission line concepts
• Smith Chart
• Microwave Design Package
• Microstrip Design Package

4
STABILITY(assuming S11lt1 S22lt1)
Stab_circle
2
1
1. Unconditionally Stable
Smith Chart
Kgt1
2. Conditionally Stable
2
1
3. Always Unstable
2
1
5
The effect of source inductance

• Changes the S-parameters
• Slightly changes the noise parameters

MESFET
6
1. Compromise between Noise and Gain
0.8dB noise circle
16dB gain circle
N
G
7
Matching Networks

• Input Matching Networks
• Output Matching Networks

IMN
OMN
Transistor
8
Biasing

• Operating Point
• Id 10mA
• Vds 3V