A comparison of sidelobe cancellation techniques using auxiliary horizontal and vertical antennas in HF surface wave radar

Sidelobe cancellation techniques are evaluated here using auxiliary horizontal and vertical antennas in a HF surface wave radar (HFSWR). The objective is to compare the pros and cons of using horizontal dipoles or vertical monopoles as auxiliary antennas in HFSWR. A radar experiment was carried out to facilitate this comparison. Four horizontal dipoles, configured in the form of two separate crosses, and six vertical monopoles of a HFSWR system were used in the experiment. In this paper, we use the central four monopoles as main antennas and either two of the horizontal dipoles or the other two vertical monopoles as auxiliary antennas. A target signal was synthesised and injected into the radar data. The effects of the cancellation techniques on the target signal are evaluated. As expected, if the target signal is coming from the same direction as the interfering signal, it is cancelled when the vertical monopoles are used as auxiliary antennas. The same target signal, however, is still visibly present when the auxiliary horizontal dipoles are used. This latter result was obtained in spite of the fact that the horizontal antennas also received the radar signal