Design and Modeling of the SuperDARN HF Log Periodic Array at the South Pole

SuperDARN is a network of some 35 high-frequency (HF) Doppler radars located in the high-latitude and midlatitude regions of the northern and southern hemispheres. The radars detect backscatter from ionospheric electron density irregularities and deduce various parameters. This paper will discuss replacement of the present array consisting of 20 HF horizontal log periodic antennas at the South Pole. These current log periodic antennas cover a frequency range of 8 to 20 MHz and maximize radiation in takeoff angles from 5 to 35 degrees. The present antennas have backlobes in the same takeoff angular sector only down 10 to 15 dB from the front main beam. It is desirable to have a much higher rejection of the backlobes (more than 25 dB) that will be shown is possible with new design methods. Furthermore, the new design will incorporate crossed-diagonal dipole elements to provide polarization measurements that are not found in any of the other SuperDARN systems around the world. The log periodic dipole elements will be formed from wires supported by insulated catenary cables and a system of support towers. Extensive modeling results are shown using FEKO antenna software for antenna performance characteristics of VSWR, gain, radiation patterns, polarization, etc.