Please find some of the Radio Frequency (RF) calculators and Electromagnetics related information that you might find it useful. More electromagnetics tool would be added as the time permits
In 1865 James Clerk Maxwell actually derived 20 equations governing theory of electromagnetism . Later in 1884, Oliver Heaviside using vector notation condensed 12 of the Maxwell's equations into famous four as shown above (Equations 1-4). Remaining eight deals with the circuit analysis.
-  Maxwell, J.C. (1865). VIII. A dynamical theory of the electromagnetic field. Philosophical Transactions of the Royal Society of London, [online] 155(155), pp.459–512. doi:https://doi.org/10.1098/rstl.1865.0008.