Chapter 4

advertisement
ELCT564
Spring 2013
Chapter 4: Microwave Network
Analysis
4/13/2015
ELCT564
1
Equivalent Voltages and Currents
Voltage is proportional to the transverse electric field
Current is proportional to the transverse magnetic field
The product of equivalent voltage and current is the power flow
The ratio of the voltage to the current should be equal to the characteristic
impedance of the line
4/13/2015
ELCT564
2
Impedance Matrices
Reciprocal Networks
Lossless Networks
4/13/2015
ELCT564
3
Example
4/13/2015
ELCT564
4
The Scattering Matrix
4/13/2015
ELCT564
5
The Scattering Matrix
4/13/2015
ELCT564
6
The Scattering Matrix
Reciprocal Networks
4/13/2015
Lossless Networks
ELCT564
7
Example: The Scattering Matrix
A two port network is known to have the following scattering matrix:
Determine if the network is reciprocal, and lossless. If port two is terminated
with a matched load, what is the return loss seen at port 1? If port two is
terminated with a short circuit, what is the return loss seen at port 1?
-0.452
6.9dB
4/13/2015
ELCT564
8
Reference Plane
4/13/2015
ELCT564
9
The Transmission (ABCD) Matrix
4/13/2015
ELCT564
10
The ABCD Parameters Examples
4/13/2015
ELCT564
11
ABCD Parameters Relation to Impedance Matrix
4/13/2015
ELCT564
12
ABCD Parameters Relation
4/13/2015
ELCT564
13
Signal Flow Graph
Nodes: Each port, I, of a microwave
network has two nodes, ai and bi. Node
ai is identified with a wave entering port I,
while node bi is identified with a wave
reflected from port i. The voltage at a
node is equal to the sum of all signals
entering that node.
Branches: A branch is a directed path
between two nodes, representing signal
flow from one node to another. Every
branch has an associated S parameter
or reflection coefficient.
4/13/2015
ELCT564
14
Signal Flow Graph Representations
4/13/2015
ELCT564
15
Signal Flow Graph Rules
Series rule
Parallel rule
Self-loop rule
Splitting rule
4/13/2015
ELCT564
16
Signal Flow Graph Example
Use signal flow graphs to derive expressions for Гin and Гout for the two-port
network shown in the above Figure.
4/13/2015
ELCT564
17
Signal Flow Graph Example
Use signal flow graphs to derive expressions for Гin and Гout for the two-port
network shown in the above Figure.
4/13/2015
ELCT564
18
TRL Network Analyzer Calibration
4/13/2015
ELCT564
19
Microstrip Discontinuities
4/13/2015
ELCT564
20
Download