1. Multichannel Link Path Analysis
Mikheil Tsiklauri, James Drewniak
Missouri S&T EMC Laboratory

2. Objectives Multichannel Link Path Analysis 2D Cross sectional Analysis
Passivity & Causality Checking/Enforcing
A modeling and S-parameters extraction tool for multilayer via transitions
Z to S-Parameters, Single-ended to Differential Convertion
The paradigm for the FEMAS development is to allow engineers performing link-path analysis, power-integrity analysis, and EMI analysis to do so in a convenient way , with commercial software quality, robustness, good computational speed, cross-platform solution, and a professional, user - friendly intuitive Graphical User Interface (GUI)

3. Outline Objectives; Link Path Analysis;
Equalization for improving eye parameters;
Cascading of S-Parameters sequence;
A passivity & causality tool;
A de-embedding tool for extracting an unknown block part of S-parameters in a cascade of blocks;
2D cross-sectional analysis;
A modeling and S-parameters extraction tool for multilayer via transitions;
A network parameters tool for conversion of S-parameters in Z-parameters, single-ended S-parameters to hybrid-mode and vice versa;

4. Link Path Analysis: Description of the scheme
Let us model the following structure (5 pieces):
- 2 Boards with microstrips; 1 Connector; 2 Cables
cable
cable
Cable
Board
Connector

5. Link Path Analysis Step 1. Load Board and connector s-parameters
Model cable s-parameters using 2D cross sectional analysis
Step 3.
Connect all blocks with channels

6. Link Path Analysis Step 4. Define source with input signal
Define input signal parameters:
VHigh/VLow
Rise/fall time
Bit rate
Bit pattern
Step Connect source, terminate port and add probe

7. Link Path Analysis
Step 6.
Run simulation

8. Link Path Analysis Step 7. View results: Channel response
It is possible to export channel response
into csv file.
Step View results: Eye diagram

9. Outline Objectives; Link Path Analysis;
Equalization for improving eye parameters;
Cascading of S-Parameters sequence;
A passivity & causality tool;
A de-embedding tool for extracting an unknown block part of S-parameters in a cascade of blocks;
2D cross-sectional analysis;
A modeling and S-parameters extraction tool for multilayer via transitions;
A network parameters tool for conversion of S-parameters in Z-parameters, single-ended S-parameters to hybrid-mode and vice versa;

10. Transmission and Receiver Side Equalization
Equalization of a channel is very important for ensuring signal integrity in a lossy channel. Several equalizer types are implemented in the current version of FEMAS. Both user-defined equalizers, and optimized equalizer parameters are implemented.
Equalization of a channel is very important for ensuring signal integrity in a lossy channel. Several equalizer types are implemented in the current version of FEMAS. Both user-defined equalizers, and optimized equalizer parameters are implemented.
Pre-emphasis and De-emphasis are implemented as a part of the transmitter, and FFE and DFE are implemented as a part of the receiver. A CTLE can be applied between any two S-parameters blocks, or at the end of the channel.
Pre-emphasis and De-emphasis are implemented as a part of the transmitter, and FFE and DFE are implemented as a part of the receiver. A CTLE can be applied between any two S-parameters blocks, or at the end of the channel.

11. FFE – Feed Forward Equalization
FFE equalization. The FFE is implemented as a multi-tap FIR filter.
Before equalization
FFE – Least square method
The optimization finds such pre-taps, post-taps and cursor coefficient that minimize the difference between a training signal at the input, and the equalized output signal. The two optimization methods applied are the Least Squares method and the Widrow-Hoff method. The eye diagram of the output signal after equalization for both methods is shown in Figure
FFE – Widrow-Hoff method
cursor, 3 Post taps, pre taps
 Equal
EH(mV)
EW(ps)
Before 46 48
LSM
114 78 WH
113 76
Eye diagrams of signal with optimized FFE equalization.

12. CTLE - Continuous Time Linear Equalization
CTLE. A CTLE is implemented as a rational transfer function with real poles and zeros.
Before equalization
The optimization gives a 2-pole 1-zero CTLE for a given DC gain, peak frequency, and peak gain with the narrowest bandwidth. The eye diagram of the output signal after the CTLE is shown in Fig
CTLE equalization
2 poles 1 zero
EH(mV)
EW(ps)
Bef. Equal 46 48
LSM Equal
227 80
WH Equal
222

13. Outline Objectives; Link Path Analysis;
Equalization for improving eye parameters;
Cascading of S-Parameters sequence;
A passivity & causality tool;
A de-embedding tool for extracting an unknown block part of S-parameters in a cascade of blocks;
2D cross-sectional analysis;
A modeling and S-parameters extraction tool for multilayer via transitions;
A network parameters tool for conversion of S-parameters in Z-parameters, single-ended S-parameters to hybrid-mode and vice versa;

14. Cascading
Cascade s-parameters blocks to obtain one equivalent s-parameters matrix from a sequence of s-parameters:
Choose “S-parameters simulation”
and define frequency samples for total s-parameters matrix
One total s-parameters will be created

15. Cascading
Cascading result:
Equivalent schemes after cascading:

16. Plot S-Parameters from LPA tool
Plot S-Parameters components

17. Outline Objectives; Link Path Analysis;
Equalization for improving eye parameters;
Cascading of S-Parameters sequence;
A passivity & causality tool;
A de-embedding tool for extracting an unknown block part of S-parameters in a cascade of blocks;
2D cross sectional analysis;
A modeling and S-parameters extraction tool for multilayer via transitions;
A network parameters tool for conversion of S-parameters in Z-parameters, single-ended S-parameters to hybrid-mode and vice versa;

18. Check S-Parameters for passivity & Causality
Open S-Parameters block in Passivity & Causality tool

19. Check S-Parameters for passivity & Causality

20. Check S-Parameters for passivity & Causality
Check S-Parameters for causality

21. Check S-Parameters for passivity & Causality
Results

22. Outline Objectives; Link Path Analysis;
Equalization for improving eye parameters;
Cascading of S-Parameters sequence;
A passivity & causality tool;
A de-embedding tool for extracting an unknown block part of S-parameters in a cascade of blocks;
2D cross-sectional analysis;
A modeling and S-parameters extraction tool for multilayer via transitions;
A network parameters tool for conversion of S-parameters in Z-parameters, single-ended S-parameters to hybrid-mode and vice versa;

23. Simple De-embedding Tool
For de-embedding task we have 2 tools. The first is simple, where user can load any number of s-parameters with the same number of ports, define location of unknown block and tool will extract the unknown s-parameters. Extracted block can be plotted or exported in touchstone file.

24. De-Embedding Tool Define Channel Define Unknown Block
User can create any complicated channel, load blocks with different number of ports. Connect them to each other by different way. “Cascaded Block” should be defined as a total block. Also in the channel should be exactly one unknown block.
Define Total Block
De-embedding Task:
There is given some complicated channel
There is given S-parameters for total channel
All s-parameters blocks in the channel is known except one
We need to find unknown s-parameters block

25. De-embedding Results Extracted block can be
The result s-parameters can be plotted, checked for causality/passivity and exported in touchstone file.
Extracted block can be
Exported into touchstone file
Opened in plot tool
Checked with passivity/causality tool

26. Outline Objectives; Link Path Analysis;
Equalization for improving eye parameters;
Cascading of S-Parameters sequence;
A passivity & causality tool;
A de-embedding tool for extracting an unknown block part of S-parameters in a cascade of blocks;
2D cross-sectional analysis;
A modeling and S-parameters extraction tool for multilayer via transitions;
A network parameters tool for conversion of S-parameters in Z-parameters, single-ended S-parameters to hybrid-mode and vice versa;

27. 2D Cross-Sectional Analysis
Define geometry: microstrip with 2 traces
During last years in our Lab there were developed algorithms for multilayer via transition calculation, by Yaojiang, Dr. Fan and others. Based on these algorithms A modeling and S-parameters extraction tool for multilayer via transitions was added. Right now input geometry is loaded from txt file. Later some interface will be created to define geometry. It is possible to load multiple input files and run all cases simultaneously. The result s-parameters will be loaded in the results section.

28. 2D Cross-Sectional Analysis
Set simulation setings
During last years in our Lab there were developed algorithms for multilayer via transition calculation, by Yaojiang, Dr. Fan and others. Based on these algorithms A modeling and S-parameters extraction tool for multilayer via transitions was added. Right now input geometry is loaded from txt file. Later some interface will be created to define geometry. It is possible to load multiple input files and run all cases simultaneously. The result s-parameters will be loaded in the results section.

29. 2D Cross-Sectional Analysis
RLGC Matrices
During last years in our Lab there were developed algorithms for multilayer via transition calculation, by Yaojiang, Dr. Fan and others. Based on these algorithms A modeling and S-parameters extraction tool for multilayer via transitions was added. Right now input geometry is loaded from txt file. Later some interface will be created to define geometry. It is possible to load multiple input files and run all cases simultaneously. The result s-parameters will be loaded in the results section.

30. 2D Cross-Sectional Analysis
Export S-parameters
During last years in our Lab there were developed algorithms for multilayer via transition calculation, by Yaojiang, Dr. Fan and others. Based on these algorithms A modeling and S-parameters extraction tool for multilayer via transitions was added. Right now input geometry is loaded from txt file. Later some interface will be created to define geometry. It is possible to load multiple input files and run all cases simultaneously. The result s-parameters will be loaded in the results section.

31. Outline Objectives; Link Path Analysis;
Equalization for improving eye parameters;
Cascading of S-Parameters sequence;
A passivity & causality tool;
A de-embedding tool for extracting an unknown block part of S-parameters in a cascade of blocks;
2D cross-sectional analysis;
A modeling and S-parameters extraction tool for multilayer via transitions;
A network parameters tool for conversion of S-parameters in Z-parameters, single-ended S-parameters to hybrid-mode and vice versa;

32. Multilayer Via Transitions Tool
Load input data from txt file and run simulation
During last years in our Lab there were developed algorithms for multilayer via transition calculation, by Yaojiang, Dr. Fan and others. Based on these algorithms A modeling and S-parameters extraction tool for multilayer via transitions was added. Right now input geometry is loaded from txt file. Later some interface will be created to define geometry. It is possible to load multiple input files and run all cases simultaneously. The result s-parameters will be loaded in the results section.

33. MVTT Results
The result s-parameters can be plotted and exported in touchstone file.

34. Outline Objectives; Link Path Analysis;
Equalization for improving eye parameters;
Cascading of S-Parameters sequence;
A passivity & causality tool;
A de-embedding tool for extracting an unknown block part of S-parameters in a cascade of blocks;
2D cross-sectional analysis;
A modeling and S-parameters extraction tool for multilayer via transitions;
A network parameters tool for conversion of S-parameters in Z-parameters, single-ended S-parameters to hybrid-mode and vice versa;

35. Convert S-parameters to Z-arameters
Convert S-parameters to Z-parameters and vice versa
In a network parameters tool we have added functionality for s to z and z to s parameters conversion. Multiple input files are allowed. The results blocks will be loaded in results table and can be plotted or exported in touchstone file.

36. Convert Single-Ended to Hybrid-Mode
Convert single ended parameter to hybrid mode
Single-ended
Hybrid-mode
In the same network parameters tool there was added conversion functionality from single ended to hybrid-mode. User will define port definition for output s-parameters. Some ports can be coupled and some can be still single ended. For each hybrid-mode port user will choose the type (single-ended or Pair). In case of pair corresponding coupled ports should be defined; In case of single-ended corresponding single-ended port number should be assigned.

37. Thank you for your attention
Questions ?
Thank you for your attention