“Rather than depend on luck and many hours spent in the EMC laboratory trying various circuit combinations, up front design and consideration of the parasitic circuit elements, the possible resonances, and the overall equivalent circuits will help the designer be successful the first time” (Page 21)
Why I Read This
I was designing a flight computer PCB following routing guidelines and common practices for PCB Design, but I wanted to know exactly why I was doing these things. So, I found this book that provides a theoretical backing to why these common practices exist so I can understand what’s really going on to make informed design tradeoffs.
What I Learned
Two coupling mechanisms: Electric Field and Magnetic Field
- Electric Field: Occurs through displacement current which has a parasitic capacitance effect
- Magnetic Field: Occurs through current and inductance
These get dangerous when they offer a lower impedance return path than the intended one.
High frequencies radiate more than lower frequencies. Often it is not the fundamental frequency that is the problem, it is the higher harmonics.
Inductance:
- At high frequencies, inductance dominates
- Lots of formulas to calculate inductance of different geometries