Direct S₂₁ Calculation Using Infinitesimal Dipole Modeling

The infinitesimal dipole modeling (IDM) technique represents the current density of the antenna under test as an array of infinitesimal dipole moments. Using the IDM concept, complicated structures of antennas and scatterers can be replaced with compact infinitesimal dipoles. With the rapid progress of antenna technology, antenna coupling analysis applicable to both near-field and far-field has become essential. The coupling phenomenon can be easily analyzed with IDM. Existing studies required additional mutual admittance calculations, and verification at the measurement level needed to be improved. In this paper, we propose an equation that directly calculates S21 from the extracted infinitesimal dipoles of the transmitter and receiver using IDM. The proposed method is demonstrated through comparison with both the numerical simulation results and measurements.