Abstract
Time‐domain reciprocity theorems of the time‐convolution and the time‐correlation type for electromagnetic fields in linear, time‐invariant, and locally reacting media are discussed. Inhomogeneous, anisotropic, and arbitrarily dispersive, both active and passive, media are included. The analysis is entirely carried out in space‐time, without intermediate recourse to the frequency or the wave vector domain. The application to inverse source and inverse constituency (or inverse profiling) problems is briefly indicated.