You are right!!! If you don't understand the return path of the signal, you can't draw a high-speed PCB well.

I have been reading a book on high-speed PCB design and PCB process published by JT recently. When I saw the return path, I thought of the questions about this knowledge point mentioned in two groups recently. The book is very good, but there will be some questions. With these questions, I also looked for relevant information. I want to combine the knowledge in the book and my own understanding as much as possible to explain this problem to everyone. If there is anything wrong, you are welcome to leave a message in the comment area. This article will explain the following five points: What is the return path of the signal? Why should we study the return path of the signal? What is the difference between the return path of the high-speed signal and the return path of the low-speed signal? How to understand that the return path of the high-speed signal is below the signal path? After understanding the return path, what should we pay attention to when designing PCB?

First of all, we need to learn the following 5 aspects:

What is the return path of the signal?

Why should we study the return path of the signal?

What is the difference between the return path of the high-speed signal and the return path of the low-speed signal?

How to understand that the return path of the high-speed signal is below the signal path?

After understanding the return path, what should we pay attention to when designing PCB?