A simple polarimetric calibration method which utilizes a reference target

A polarimetric measurement radar can be calibrated with a simple, single calibration target method rather than the more complex multiple calibration target method if the transmit matrix and receive matrix are symmetric and identical. Because of the presence of nonreciprocal devices such as switches and circulators in the RF network, the matrices are usually different and nonsymmetric. However, the symmetry can be restored and the effective transmit and receive matrices can be made identical through the use of a reference target. In addition, this method has no phase ambiguity associated with the cross-polarized terms as with other single target methods. When the test object measurement matrix elements are defined by target/reference ratios, the effective antenna matrix can be obtained, inverted, and applied on both sides of the measurement matrix to provide calibrated polarimetric data. Application of the method to the measurement of a 12" sphere is shown.<>