White Paper: Designing Log Periodic Antennas

By Dr. Glen Dash, Ampyx LLC

In 1957, R.H. DuHamel and D.E. Isbell published the first work on what was to become known as the log periodic array. These remarkable antennas exhibit relatively uniform input impedances, VSWR, and radiation characteristics over a wide range of frequencies. In essence, log periodic arrays are a group of dipole antennas of varying sizes strung together and fed alternately through a common transmission line. Still, despite its simplicity, the log periodic antenna remains a subject of considerable study even today.