## Abstract

A Newton-type method for the reconstruction of inhomogeneous 3-D complex permittivity variation of arbitrary shaped materials loaded in a rectangular waveguide is presented. The problem is first formulated as a system of integral equations consist of the well-known data and object equations, which contain the dyadic Green's function of an empty rectangular waveguide. Two unknowns of this system are solved in an iterative fashion by linearizing one of them, i.e., the data equation in the sense of the Newton method, which corresponds to a first-order Taylor expansion of the related integral operator. Since the problem is severely ill posed by nature, a regularization in the sense of Tikhonov is applied to the data equation. A detailed numerical implementation of the method, together with some numerical examples are also given to show the capabilities and validation limits of the method.

Original language | English |
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Article number | 5445022 |

Pages (from-to) | 1290-1296 |

Number of pages | 7 |

Journal | IEEE Transactions on Microwave Theory and Techniques |

Volume | 58 |

Issue number | 5 PART 1 |

DOIs | |

Publication status | Published - May 2010 |

### Funding

Manuscript received August 04, 2009. First published April 08, 2010; current version published May 12, 2010.This work was supported by The Scientific and Technological Research Council of Turkey (TUBITAK) under Grant 108E146. E. Kılıç, F. Akleman, D. Merve Özaltın, Ö. Özdemir, and A. Yapar are with the Department of Electronics and Communication Engineering, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey (e-mail: [email protected]). B. Esen is with the Electrical and Electronics Engineering Department, Balıkesir University, 10100 Balıkesir, Turkey. Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. Digital Object Identifier 10.1109/TMTT.2010.2045528

Funders | Funder number |
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TUBITAK | 108E146 |

Türkiye Bilimsel ve Teknolojik Araştirma Kurumu |