In the past documents, I’ve explained how inductors and capacitors behave at high/low frequencies with respect to impedance/reactance. The issue is, that explanation was based on theoretical assumptions about inductors and capacitors. Essentially, we were assuming ideal components.
Since we’re dealing with such high frequencies, it’s important to understand just how our components are going to behave. For this reason, this document will attempt to explain how our passives can behave at high frequencies in a non-ideal sense. We will also see how this affects our component selection.
Before understanding how capacitors and inductors behave at high frequency, we should first understand what they are physically. Both are energy storage devices, but they accomplish this energy storage in two very different ways.
You've probably already learned about this if you’ve already taken a circuits course. However, I’ll go over it as a quick refresher because it's something that's easy to forget when getting caught up in all the math behind them.
Capacitors use electric fields to store energy. They are constructed from 2 parallel plates (electrode) with an insulator in between (dielectric). This can be seen in the figure below.