Polarization characteristics of resistively loaded orthogonal dipoles excited by ultra wideband signals

Polarization characteristics of the radiated electric field in free space at far distances from resistively loaded thin half-wave orthogonal dipoles excited by short pulses are investigated. It is shown that the radiated field can become circularly polarized in the broadside direction when the exciting input voltage is sinusoidal and the input to the x-axis dipole is the same as the input to the z-axis dipole but delayed by a quarter cycle. The Wu-King loading profile (see Wu, T.T. and King, R.W.P., IEEE Trans. Antennas and Propagation, vol.13, p.369-73, 1965) is considered here. These results are compared with that of the radiated field of unloaded orthogonal dipoles excited by finite cycles of sinusoids.