On the radiation self-impedance and mutual impedance of horn appertures

Precise tables of self-impedance and mutual impedance for dipole antennas are available, but those for horn antennas are still in need, With the development of auto-tracking, phased arrays and beamstacks, a new demand for sets of tables and curves for aperture feeds arises. In this paper, formulas for self-impedance and mutual impedance of waveguide radiators are derived by the plane wave angular spectrum method. Thirty sets of self- and mutual impedance curves for different apertures are worked out with the aid of electronic computers. These results fit well with the experiments on standard wave guide feeds. A set of mutual impedance curves for narrow aperture antennas is also plotted out according to the plane wave angular spectrum concepts. By duality, very good coincidence occurs between these curves and classical half wave dipole curves. Some relations on antenna parameters and linear aperture antenna correlations are also derived.