Reduction of the anomalous resonances of symmetric log-periodic dipole antennas

Computer analysis reveals that the anomalous behavior of symmetric log-periodic dipole antennas (LPDA) is mainly due to the radiation of the dipole elements in the anomalous radiating region which is excited by the transmission line resonance of the feed structure. By replacing the cylindrical dipole elements in the LPD antennas with wide-angle triangular-outline dipoles with central wires, the computed anomalous back lobe peaks are reduced to negligible levels. LPD antennas were constructed using wide-angle triangular-outline dipoles with central wires, and they were found to exhibit satisfactory performance.