The Experimental System PALES: Signal Separation with a Multibeam-System Based on a Rotman Lens

The experimental system PALES is described: a multi-functional array antenna in the X band with broadband beamforming by a Rotman lens. Studies that have been conducted about possible broadband antenna elements have implied the use of flared-notch antennas (Vivaldi antennas), which are specified in the paper. A short description of the Rotman lens design used is given. The receiver branch of the PALES system, the applied signal model, and different broadband array-processing methods, which can be applied to the received signals of a multibeam system, are discussed. To separate broadband signals with a small angular separation, the ICA (independent component analysis) method shows superior performance compared to ML (maximum likelihood) estimation, based on superresolution by the STCM (steered covariance matrix) method.