Electrical and Computer Engineering
Department of Electrical and Computer EngineeringUniversity of Illinois Urbana-Champaign


Current distribution calculations

Antenna design and simulations

Sensor modeling

RCS & Bi-RCS computations

Current distributions on metallic plates

Inverse scattering simulations

Radargrams of buried pipes

Experimental inverse scattering

Borehole measurements





Monostatic and Bistatic RCS Computations: Hybrid Finite-Element Boundary-Integral Method for 3D Scattering

The main idea of this hybrid method is to use a Finite-Element formulation in the interior region of the discretized scattering object and a Boundary-Integral Equation formulation in the exterior region. For more information about this technique, please refer to Prof. Jianming Jin's book, ``The Finite Element Method in Electromagnetics '', whose description can be found here.

In the following, numerical simulation results will be shown. The problems are solved using the Multi-Level Fast Multipole Algorithm (MLFMA), and matrix inversions are using a Conjugate Gradient (CG) method. If you want to know more about the MLFMA, check this page.

The first Figure shows the test object, a coated sphere. The second one shows the normalized residual norm versus the number of iterations in the CG solution of scattering by a coated sphere, for both interior resonant and non-resonant cases. Then, the two following Figures show the bistatic RCS of the coated sphere, for both resonant and non-resonant cases. Good results are obtained using the new hybrid formulation (labeled TENENH).

Coated sphere

Normalized residual norm, non resonant case

Normalized residual norm, resonant case

Bistatic RCS of the coated sphere, non resonant case

Bistatic RCS of the coated sphere, resonant case

The following two Figures compare the accuracy of the computed RCS with the analytical Mie-series solution as a function of the number of levels in the Fast Mulipolt Method.

RCS of the coated sphere with a 4-level FMM

RCS of the coated sphere with a 5-level FMM

The final two Figures show the computation of the monostatic RCS of two real objects: a Northrop wing and a NASA almond. More information about these results are self-contained in the Figures.

RCS of the Northrop wing

RCS of the NASA almond

The above work is a collaboration between X.Q. Sheng, Dr. JinMing Song, Dr. Caicheng Lu, Prof. Jianming Jin, and Prof. Weng Cho Chew. Please send suggestions, comments, and inquiries to: song@sunchew.eceuiuc.edu.