The Design of an Antenna Array Used for the Suppression of Es Layer Clutter

There has Es layer clutter in the high frequency surface wave radar, and the Es layer clutter has the difference polarized characters with the signal. Horizontally polarized antennas can be added as auxiliary antennas in the high frequency surface wave radar system that uses vertically polarized antennas to suppress the Es layer clutter. The clutter-to-signal ratio in the outputs of the auxiliary antennas will affect the suppression of the Es layer clutter in the main antennas. The bigger of the clutter-to-signal ratio in the outputs of the auxiliary antennas, the better suppression result of the Es layer clutter in the main antennas achieved. In order to increase the clutter-to-signal ratio in the outputs of the auxiliary antennas, an antenna array consists of three horizontally polarized antennas is proposed in this paper. Using the superdirective synthetically method, the mainlobe of the auxiliary horizontally polarized antenna array is put on the direction of the Es layer clutter arrival direction, and a low sidelobe is put on the direction of the signal arrival direction. Then the auxiliary horizontally polarized antenna array will have a big gain on Es layer clutter and a little gain on signal. So the clutter-to-signal ratio in the outputs of the auxiliary horizontally polarized antenna array will be increased, the suppression of the Es layer clutter in the main antennas which use the horizontally polarized antenna array as auxiliary antenna will be more effective.