Polarimetry With Phased Array Antennas: Sensitivity and Polarimetric Performance Using Unpolarized Sources for Calibration
Journal article, 2012

Polarimetric phased arrays require a calibration method that allows the system to measure the polarization state of the received signals. In this paper, we assess the polarimetric performance of two commonly used calibration methods that exploit unpolarized calibration sources. The first method obtains a polarimetrically calibrated beamforming solution from the two dominant eigenvectors of the measured signal covariance matrix. We demonstrate that this method is sensitivity equivalent to the theoretical optimal method, but suffers from an ambiguity that has to be resolved by additional measurements on (partially) polarized sources or by exploiting the intrinsic polarimetric quality of the antenna system. The easy-to-implement bi-scalar approach assumes that the feed system consists of two sets of orthogonally oriented antenna elements, each associated with one polarization. We assess its sensitivity and polarimetric performance over a wide field-of-view (FoV) using simulations of a phased array feed system for the Westerbork Synthesis Radio Telescope. Our results indicate that the sensitivity loss can be limited to 4.5% and that the polarimetric performance over the FoV is close to the best achievable performance. The latter implies that the intrinsic polarimetric quality of the antennas remains a crucial factor despite the development of novel polarimetric calibration methods.

self-calibration

calibration

far-field radiation pattern

polarimetry

dynamic-range

wide-field

understanding radio polarimetry

Beamforming

phased array antennas

Author

S. J. Wijnholds

Netherlands Institute for Radio Astronomy (ASTRON)

Marianna Ivashina

Chalmers, Signals and Systems, Communication and Antenna Systems, Antennas

Rob Maaskant

Chalmers, Signals and Systems, Communication and Antenna Systems, Antennas

K. F. Warnick

Brigham Young University

IEEE Transactions on Antennas and Propagation

0018-926X (ISSN)

Vol. 60 10 4688-4698 6236092

Areas of Advance

Information and Communication Technology

Subject Categories

Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.1109/TAP.2012.2207340

More information

Latest update

4/3/2018 3