An independently-fed log-periodic antenna for directed pulsed radiation

An antenna capable of radiating a band-limited pulse with minimal distortion, negligible loss and significant directivity is reported. A design was derived by modification of the conventional log-periodic dipole array to permit independent feeding of each dipole. This was modelled with an electromagnetic field computation program using the time-domain integral equation method and iterated to find a design that minimised phase dispersion across the operating frequency band. The antenna constructed was found to give a good-quality radiated pulse in the main beam direction, with weaker and dispersed waveforms in other directions, indicating significant directive gain.