Broadband and robust adaptive antenna under correlation constraint

This paper deals with a robust adaptive antenna which suppresses the interference with good protection of the broadband desired signal under imperfect setting of directional constraint. The new guiding principle adopted to control the adaptive antenna is to minimise the output power under the constraint on the cross correlation between the desired signals at the input and output of the array. Accordingly, the principle is named correlation-constrained minimisation of power (CCMP) method. The constraint to protect the desired signal is determined by the a priori knowledge of the characteristics of the desired signal in terms of its direction of arrival and frequency spectrum. The performances of CCMP and its modified version (improved CCMP) are demonstrated by numerical calculation. The results show that the improved CCMP method achieves high SINR (signal-to-interference-plus noise ratio) and low distortion of the output desired signal even when the desired signal is broadbanded and signal direction is not exact. The limit of the pointing error where the system can function satisfactorily is also discussed.