Bogatin’s Practical Guide to Transmission Line Design and Characterization for Signal Integrity Applications

The following are a collection of videos and downloads that are associated with the textbook, Bogatin’s Practical Guide to Transmission Line Design and Characterization for Signal Integrity Applications, published by Artech, in 2020.

This textbook is the definitive guide to building your engineering understanding of the essential principles of how signals interact with transmission lines and how to engineer transmission lines to achieve target properties.

If you find any of these videos of value, you will want to purchase this textbook to gain that fundamental understanding all engineers need to excel as designers.

Section 1.1: Transmission Line book introduction 

This is an overview of the textbook. Why I wrote this textbook to provide engineering insight into the behavior of transmission lines and the organization of the book.

Section 2.3: ZIP File: Simulation tool download

This is a free tool you can download and use to build your engineering intuition about the dynamic nature of signals. Watch the signal as it propagates and interacts with impedance changes.

Simulation tool walkthrough

This is the user guide for using the very cool TDR animation tool to visualize the interactions of signal on interconnects. I show you how to set up a few cases which show propagating and reflecting signals.

Section 2.5: Instantaneous and Characteristic impedance of TR line analysis

This is the most important concept in the textbook. It reviews the concept of instantaneous impedance and what a signal sees as it encounters a real transmission line.

A.S. Gilmour ARTECH book site can be found here.

Section 2.11: Signal-return current waveform propagating down TR line

This video helps you visualize how a signal propagates on a transmission line and how the signal current and the return current propagates down a transmission line. It shows the displacement current propagating in a transmission line.

If you find any of these videos of value, you will want to purchase this textbook to gain that fundamental understanding all engineers need to excel as designers.

Section 4.5: The input impedance of a transmission line

This video explains what the input impedance of a transmission line and how a signal is launched as a voltage into a transmission line.

Section 5.2: The boundary conditions between two different transmission lines

I explain the conditions on the voltage and the current where two transmission lines connect. This is the basis of understanding why there are reflections.

Incident reflected and transmitted voltage and current

This video sets up the relationship for the currents and voltage in the two regions where two transmission lines meet. This is the next step to understand why there are reflections. 

Algebraic derivation of reflection and transmission coefficient

I answer the question why there are reflections and how we can calculate the reflection coefficient and the transmission coefficient, based on the boundary conditions. 

Section 5.3: Signal propagation in TR lines to and from interface

What happens when a signal encounters the interface between two transmission lines and a reflected signal is created and the transmitted signal is changed?

Section 5.7: Reflections from open and short w/ resulting dynamic voltage video on TR line

This video explains what happens to a signal when it encounters different impedances at the end of a transmission line. If you do not understand reflections, the behavior of the currents is very confusing. But I show you the inner workings of the current so it becomes obvious.

Section 5.8: TR Line analysis and steady-state simple source and load analysis

This video resolves the paradox. Why do we see a 2 v signal at the end of a transmission line if we only sent a 1 V signal into the line?

If you find any of these videos of value, you will want to purchase this textbook to gain that fundamental understanding all engineers need to excel as designers.

Section 6.1: Dynamic signal reflection example

This videos shows the dynamics of a signal coming from a low impedance driver and reflecting back and forth in a transmission line to illustrate the dynamics of the reflections.

Section 6.3: Dynamic reflection sim tool

Here, you can download the TDR reflection animation tool again, if needed.

Dynamic reflection tool intro

Here are some of the other features in this simple reflection tool to show off the dynamic nature of signals. 

Section 7.1: Scope probe compensation experiment walkthrough

I bring you into my lab to look at a signal measured by my scope, which seems to show that a longer cable increases the rise time of a signal. Don’t be fooled! 

Section 7.5: Verifying the explanation of the longer rise time with cable length

We look at the details of why the rise time SEEMS to increase with cable length and what is really going on using a few simple consistency tests.

If you find any of these videos of value, you will want to purchase this textbook to gain that fundamental understanding all engineers need to excel as designers.

Section 8.5: Quite Universal Circuit Simulator Download site

Here, you can download my favorite free high performance SPICE simulator, QUCS.

Chapter 8.8 Circuit files – AC transient simulation

Here, you can download a few circuit files to use with QUCS. These circuit files will allow you to simulate a TDR, just like a show in the videos.

QUCS & Simulation tutorial

Here, I get you started in building your first QUCS circuit and performing a simulation using the files you can download. 

Section 8.6: TR model comparison – measured vs ideal

I show you how you can compare the measured input impedance of a real transmission line and compare this to the simulated input impedance of an ideal transmission line.

Remember, all the details of the essential principles are described in the textbook. 

Section 8.8: Is a transmission line an inductor or a capacitor

This video explains why we can think of a transmission line as a capacitor or inductor at low frequency. This model breaks down at a frequency that depends on its length.

Section 8.10: How well can we model an ideal transmission line model with an LC model

An ideal transmission line model is NOT a collection of LC models. It is fundamentally different. This video shows why you should never model a transmission line as a collection of LC elements if you have an ideal transmission line model available. 

If you find any of these videos of value, you will want to purchase this textbook to gain that fundamental understanding all engineers need to excel as designers.

Section 9.6: Time Domain Reflectometer (TDR) to measure impedance profile of interconnects

I introduce you to a simple, easy to use TDR to measure the instantaneous impedance profile of a few transmission lines.

Remember, all the details of the essential principles are described in the textbook.

Section 9.8: Electrically long & short interconnect transition QUCS file

Here, you can download a collection of QUCS files to play along at home with the TDR simulations and measurements.

Electrically long and short interconnects

In this video, I explain the difference between an electrically long and an electrically short interconnect based on it length and the rise time being used to probe the transmission line.

Spatial resolution simulation

In this video, I show what it means to describe the resolution of a TDR. What does it take to resolve two adjacent discontinuities?

Section 10.1: Demonstration measurement with TDR

In this experiment, we use a TDR to measure the impedance profile of a transmission line and interpret the results.

Section 11.6: Calculator to calculate dielectric constant and correction factor for microstrips

Here is a link to a simple online tool to calculate the characteristic impedance of a microstrip transmission line. It is an approximation.

If you find any of these videos of value, you will want to purchase this textbook to gain that fundamental understanding all engineers need to excel as designers.

Section 12.3: Polar Instruments SI9000 commercial 2D field solver info site

Here is a link to the polar instruments SI9000 tool, one of the simplest to use transmission line designers that uses a 2D field solver.

Polar Instruments SI9000 free 2-week evaluation license contact link. Here, you can request a 2 week evaluation license to the polar tool to try it out.

Section 13.2: SI9000 design space mapping tutorial

Here, we explore design space to see how changing the dielectric thickness of a microstrip affects its characteristic impedance. This is the analysis of a design.

Section 14.2: Symmetrical stripline approximation online calculator

This is an example of another online impedance calculator.

Section 14.3: PCBway internet fab website

This is a link to a very popular PCB fab shop located in mainland China.

Section 15.3: Fundamental principle of differential impedance

I offer the best way of thinking about a differential pair and differential impedance. This will eliminate a lot of confusion you may have about differential pairs. 

Section 15.7: When one line is part of a differential pair

The original of the three different impedances one line has that is also in a differential pairs is identified in this video. Remember, the essential principles are covered in the textbook.

Section 15.8: Odd mode impedance

Here we see the origin of the odd mode impedance of a line that is part of a pair.

Section 15.9: A common signal

Here we see the impedance of one line in a pair when the pair is driven with a common signal. This is the origin of the even mode impedance.

If you find any of these videos of value, you will want to purchase this textbook to gain that fundamental understanding all engineers need to excel as designers.

Section 16.1: Differential TDR

In this video I introduce you to a differential TDR and what it really measures. 

Section 17.2: Tightly vs loosely coupled differential microstrip comparison video

In this video I answer the question, which is better, tightly or loosely coupled differential pairs.

Section 18.6: TDR measurement of diff pair with a large gap in the return path

What happens in a differential pair when the return path is removed from under the differential pair? See this analysis and measurement.

Section 19.3: Quite Universal Circuit Simulator (QUCS) source forge download link

Once again, here is the link to download QUCS so you can play along at home with the experiments.

Section 19.4: QUCS chapter 19 examples ZIP archive

Here, you can download the simulation files for QUCS.

Walkthrough of QUCS example archive circuit files

Here I walk you through how to begin the process of hacking some interconnects using QUCS.

Section19.6: Circuit A walkthrough

In this video you will see how to model a discontinuity as a C, L or short transmission line and simulate these behaviors in QUCS.

Simple TR DUT hacking example

In this video, I show you how to hack a circuit model to match the measured TDR response from an interconnect. 

Section 19.9: Multiple TR DUT hacking example

Here, we will hack a more complex equivalent circuit model to match the simulation with a measure TDR response. This is how we use a TDR measurement to build a model of a discontinuity of the structure under test.

Section 19.12: Thru-hole axial lead resistor + TR line hacking model

Here, we hack a model for a real terminating resistor using the measured TDR response. Using this model we can evaluate the useful bandwidth for using this resistor. 

BeTheSignal website

Here is a link to the Signal Integrity Academy website where there is a lot of additional content.

If you find any of these videos of value, you will want to purchase this textbook to gain that fundamental understanding all engineers need to excel as designers.