Performance evaluation of the adaptive sidelobe canceller system with various auxiliary configurations

In practical radar systems, the conventional adaptive sidelobe canceller (SLC) works very well as long as the input signal-to-interference-plus-noise (SINR) ratio is low or when the desired signal is known to be absent during certain time intervals. However, under high SINR, attenuation in the direction of the desired signal is inevitable. In this paper, the conventional sidelobe canceller is improved by replacing the separate auxiliary antennas by a number of existing elements of the main antenna array. This modification makes the proposed SLC different from the conventional one because the desired signal components of the main channel and auxiliary signals may be correlated. Such correlation may cause serious attenuation in the desired signal especially when the number of reused elements from both of the main array and auxiliary antenna is increased. The resulting malfunctioning of the desired signal cancellation is eliminated by adjusting the weights of the reused elements to produce a specific cancellation pattern. The required cancellation pattern should have two main features: first, it should have a level equal to that of the main array pattern at the interferer direction. Second, it should have a very low level or a null at the direction of the desired signal. The simulation results show that good performance for interference cancellation, maintaining a distortionless response for the desired signal, and low sidelobe level can be obtained by using the proposed technique. Besides the simplicity and low cost, the other advantage of the proposed SLC is that it can work effectively regardless of the strengths of the desired signal.