-
- News
- Books
Featured Books
- pcb007 Magazine
Latest Issues
Current IssueAdditive Manufacturing
In this month’s issue, we explore additive manufacturing technology for the PCB fabricator: where it stands today, the true benefits, and where it seems to be headed.
The Growing Industry
In this issue of PCB007 Magazine, we talk with leading economic experts, advocacy specialists in Washington, D.C., and PCB company leadership to get a well-rounded picture of what’s happening in the industry today. Don’t miss it.
The Sustainability Issue
Sustainability is one of the most widely used terms in business today, especially for electronics and manufacturing but what does it mean to you? We explore the environmental, business, and economic impacts.
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - pcb007 Magazine
Estimated reading time: 1 minute
Contact Columnist Form
How Electromagnetic Fields Determine Impedance, Part 1
We talk a lot about trace dimensions and relationships when discussing signal integrity issues. In particular, we like to talk about how close traces are to underlying planes and how close traces are to each other. But there is another way to think about things that is sometimes much more practical and intuitive, and that is by thinking about the electromagnetic field around the trace(s) we are considering. The position and shape of the electromagnetic field can tell us a lot about trace impedance, EMI and crosstalk coupling, and signal propagation speed.
When a current flows down a conductor an electric field and a magnetic field radiates away from that conductor. Collectively, this is called the electromagnetic field. What is important to note is that this field always exists. Furthermore, the electromagnetic field and the current are inseparable. That is: (a) the electric field can’t move ahead of the magnetic field; (b) the magnetic field can’t move ahead of the electric field; and (c) neither field can get ahead of or fall behind the current itself. They all have to move together along the conductor.
Read the full column here.
Editor's Note: This column originally appeared in the August 2013 issue of The PCB Design Magazine.
More Columns from Brooks' Bits
Brooks' Bits: Internal Trace Temperatures—More Complicated Than You ThinkBrooks' Bits: Electromagnetic Fields, Part 3 - How They Impact Coupling
Brooks' Bits: Electromagnetic Fields, Part 2: How They Impact Propagation Speed
Brooks' Bits: How Electromagnetic Fields Determine Impedance, Part 1
Trace Currents and Temperature, Part 4: Via Heat
Trace Currents and Temperature, Part 3: Fusing Currents
Trace Currents and Temperature, Part 1: The Basic Model
The Skinny on Skin Effect, Part 3: Crossover Frequency