A Systematic Approach to Optimize Calibration of Active Phased Array Structures
(Room 203)
18 Oct 18
4:00 PM
-
4:30 PM
Tracks:
Test & Measurement
Calibration is required for phased array systems with the aim of steering antenna beam to desired direction. In the process of steering the beam, each antenna elements is fed by a definite phase shift and amplitude level with respect to other elements. In the case of phase and amplitude errors, antenna pattern may diverge from required in such a way that beam direction squints and side lode levels increase, which directly reduce the performance of the systems. Several different calibration techniques are listed in the literature to optimize the performance for phase array systems. One of them is the pre-instalment calibration known as factory calibration, which is a challenging issue for very large active phased array systems when the transmitter/receiver blocks are required to be integrated with its antenna array and it's a prerequisite even if online-characterization in the field is realizable for the systems. During factory calibration, there are several issues complicates the calibration algorithm and extends measurement time such as wide frequency band, huge element numbers, temperature variations, driving power levels, beamformer resolutions etc. Subject of the proposed paper offers a consistent calibration method to optimize these functional and environmental effects for different array performances. The method starts from the antenna array pattern analysis to define the desired max phase/amplitude errors, defines required measurement conditions by examining each of these effects and ends with the optimum measurement time for factory calibration. The method also suggest a way to handle factory calibration update without measuring the whole structure in case of part replacement in the field. It is realized for a ground based active phased array radar including the factory calibration and online characterization.