I have defined Planck's constant from electromagnetic fields. I've done this by describing a shear wave oscillation that looks like a pendulum process. The wave halves accelerate in a sinusoidal process back and forth from positive half the wavelength to negative half the wavelength. The distance, angle and velocity match what is needed to describe Planck's constant as an electromagnetic process. See my website for the Microsoft Word, Excel and C# function files.
edit (8/2/2021) I've updated the files with current fine structure constant calculations.
edit (8/4/2021) Improved the accuracy of the fine structure constant to 6.5 digits using wave pendulum effect.