Application of Fourier Transforms for Microwave Radiometric Inversions

John J. Holmes, Constantine A. Balanis, William M. Truman

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Existing microwave radiometer technology now provides a suitable method for remote determination of the ocean surface's absolute brightness temperature. To extract the brightness temperature of the water from the antenna temperature, an unstable Fredholni integral equation of the first kind is solved. Fourier transform techniques are used to invert the integral after it is placed into a cross correlation form. Application and verification of the methods to a two-dimensional modeling of a laboratory wave tank system are included. The instability of the ill-posed Fredholm equation is examined and a restoration procedure is included which smooths the resulting oscillations. With the recent availability and advances of fast Fourier transform (FFT) techniques, the method presented becomes very attractive in the evaluation of large quantities of data. Actual radiometric measurements of sea water are inverted using the restoration method, incorporating the advantages of the FFT algorithm for computations.

Original languageEnglish (US)
Pages (from-to)797-806
Number of pages10
JournalIEEE Transactions on Antennas and Propagation
Issue number6
StatePublished - Nov 1975
Externally publishedYes

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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