Retarded potentials — delayed EM potentials from time-varying sources
What retarded potentials are: electromagnetic scalar/vector potentials evaluated at the delayed time $latex t-R/c$, and why causality appears in antenna theory.
maxwell's equations
From Maxwell’s equations to antenna array – part 1
Antenna models — reading order Maxwell’s equations (this article) Retarded potentials Near-field / far-field boundary Far-field retarded potentials Array pattern multiplication Dipole power gain patterns Introduction Antenna theory is Maxwell’s equations plus boundary conditions and a far-field approximation. Before retarded potentials and array factors, write the four laws carefully—especially Ampère’s law with Maxwell’s displacement current. … Read more