Vertically Polarized Dipoles and Monopoles, Directivity, Effective Height and Antenna Factor

Abstract

The effective length (Le) of linear antennas like dipoles and the effective height (He) of monopoles shorter than a wavelength are determined using a transmitting Hertz Dipole as a reference. Effective Receiving Area (AeR) has been calculated in the receiving mode and hence the Antenna Receiving Directivity (DR) or Gain (GR)) can be determined. From these calculations, it can be seen that the Received Power (WR) in a link between two dipole antennas in free space or between two monopole antennas over a perfect ground is of the same value in the far field region. As a result, the directivity or gain of the ideal dipole antenna in free space has the same value in transmission and reception; but, a different value for monopole and dipole antennas installed over a perfect ground plane. This result is fulfilled in the ideal as well as the real case where losses and mismatchings are involved.