Antennas for a 19 MHz groundwave radar

High-frequency (HF) radars operate in the frequency band 3-30 MHz to obtain performance that in some respects conventional microwave radars cannot achieve. The design of a typical antenna system for a small HF radar is described. Conventional antenna methods are used in conjunction with computer-aided design using an optimisation algorithm in general use. The conventional small HF radar tends to use a single transmit antenna illuminating the entire area of coverage with a high radiation efficiency, in conjunction with a broadside array of relatively small, slightly lossy, and cheap elements to provide narrowbeam reception. In the present case, the narrow bandwidth (10.5%) allowed the use of Yagi-Uda antennas both for the transmit antenna and for each element of the receive array