WIP - High frequency circuits

Recall that all the circuit-analysis techniques you might be familiar with from the DC domain (multi-nodal analysis, KCL, KVL, voltage divider, etc) work just as well for AC circuits. You only need to express current, voltage, and impedance values in the frequency domain through phasors which have a real and imaginary component (or else are expressed by a magnitude and an angle). Also note that signals of differing frequencies do not interact with each other and ought to be separated through Laplace transformation if necessary. One significant complication is how the category of 'impedances' expand from just resistance to capacitance and inductance as well:

Taken from slideset notes for ELEC 202, replace with a better-formated image?

One important consequence of the above is that inductors increase in overall impedance at high frequencies while capacitors decrease in overall impedance at high frequencies. This is significant because ALL conductive materials have some parisitic capacitance with other conductive materials meaning they will leak current at high enough frequencies.

Parisitic Capacitance Mitigation Strategies:

• More spacing between elements

• Less parallel geometry between elements

• Use shielding (grounded material) in between elements

• Decrease trace width, thinner traces have less capacitance

• Remove sections of the grounded plane in a PCB

• Reduce amplification (miller capacitance)