A critical study of the circuit relations of two distant antennas

In this work, we present a critical study of the circuit relations for two distant coupled antennas: either both are transmitting, or one is transmitting and one is receiving. We found that Carter´s two mutual impedances, Z₁₂ and Z₂₁, are not applicable to these two cases. Two sets of circuit relations have been formulated, with two sets of wave impedances, to characterize these new circuit relations. It is shown that the coupled wave impedances are not equal to each other, and they satisfy a conjugate relation with a negative sign. Such a relation also applies to Carter´s Z₁₂ and Z₂₁.