Calibration of smart antenna systems: measurements and results

Abstract

Smart antennas (SAs) are viewed as a candidate enabling technology for modern wireless communication systems to increase network capacity and facilitate location-based services. By conducting measurements on an SA test-bed, the signal distortion introduced by the implementation of a practical system can be analysed. This distortion can have significant impact on the estimation of signal wavefronts. Measurements have been conducted at the system, sub-system and component levels, using an SA developed for this purpose and employing a uniform circular array. This has enabled the error introduced by an implemented system to be examined. Calibration procedures are developed to overcome these implementation limitations. The cause and effects of these errors are examined, and system manufacturing tolerances and temporal thermal effects on the analogue sub-systems are shown to be the major contributor to this error; these results are presented and analysed.