Accession Number : ADP006391

Title :   Millimeter Wave Polarimetric Scatterometer Systems: Measurement and Calibration Techniques,

Corporate Author : MICHIGAN UNIV ANN ARBOR DEPT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE

Personal Author(s) : Kuga, Y. ; Sarabandi, K. ; Nashashibi, A. ; Ulaby, F. T. ; Austin, R.

Report Date : SEP 1991

Pagination or Media Count : 5

Abstract : The target and system phase-stability during the time to measure the scattering matrix is a major problem for millimeter wave polarimetric radars. This is particularly true for network analyzer-based systems. To circumvent this phase-stability problem, we have developed new fully polarimetric radars at 35 and 94 GHz. The system is based on a relatively inexpensive network analyzer and is capable of operating in either the coherent or the incoherent polarimetric measurement mode. In the coherent mode, the scattering matrix can be measured within 2 ms. In the incoherent mode, the average Mueller matrix is measured directly by transmitting four different polarizations and measuring the Stokes vector of the backscattered signal. To compare the performance of the true measurement modes, the average Mueller matrix and the statistics of the phase difference of the two co-polarized signals were measured for a rhododendron tree and for a metallic tree. The average Mueller matrices obtained from the coherent and incoherent polarimetric measurement modes were similar. The target motion during the data acquisition period did not change the average Mueller matrix in the incoherent measurement mode. The probability density function of the phase difference of the two co-polarized signals computed from the average Mueller matrix is essentially the same as the one measured with the coherent polarimetric measurement mode.

Descriptors :   *TARGET DETECTION, *POLARIMETRY, *RADAR, ACQUISITION, ANALYZERS, DATA ACQUISITION, DENSITY, FUNCTIONS, MEASUREMENT, MILLIMETER WAVES, MOTION, NETWORKS, PHASE, PROBABILITY, PROBABILITY DENSITY FUNCTIONS, SCATTERING, SIGNALS, STABILITY, STATISTICS, TARGETS, TIME, TRANSMITTING, TREES, SCATTEROMETERS, LAND USE, GROUND CLUTTER, MILITARY EQUIPMENT, COHERENT RADAR, FORESTS, VEGETATION.

Subject Categories : Active & Passive Radar Detection & Equipment
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE