MICROWAVE IMAGING OF THE BRIGHTNESS TEMPERATURE DISTRIBUTION OF EXTENDED AREAS IN THE NEAR AND FAR-FIELD USING 2-DIMENSIONAL APERTURE SYNTHESIS WITH HIGH-SPATIAL-RESOLUTION

Aperture synthesis is an attractive alternative to conventional passiv e microwave imaging systems for remote sensing applications. Whenever a high spatial resolution is desired or the imaging process should wor k like an optical camera or when microwave remote sensing in the near field has to be distance adaptive, conventional systems cause a lot of problems. However, aperture synthesis for practical applications requ ires a lot of single receivers and correlators. This can cause other p roblems because of the large number of possible imperfections. To get an estimation of such effects, the imaging expressions for the apertur e synthesis principle are developed for the near-and far-field conditi ons of a real system. To support the theory and to get an estimation o f the feasibility of this imaging method, a simple experimental system is described and experimental results of high spatial resolution for the near and far field are shown. For the near-field case a special re construction algorithm was developed and is described theoretically an d validated by the experiments. A discussion of the temperature resolu tion of aperture synthesis concludes the paper.