Edward F Kuester

US Patent:

53315677, Jul 19, 1994

Filed:

Aug 22, 1991

Appl. No.:

7/748577

Inventors:

Hugh T. Gibbons - Louisville CO
Edward F. Kuester - Boulder CO

Assignee:

The University of Colorado Foundation, Inc. - Boulder CO

International Classification:

G06F 1560

US Classification:

364481

Abstract:

Wall coverings for anechoic chambers are disclosed having an array of lossy pyramid cone material mounted on multiple backing layers of absorbing material. The number of backing layers to be used, their physical dimension (thickness) and their material properties (conductivity and permittivity) are selected so as not to modify the high frequency (UHF) behavior of the pyramid structure, while at the same time providing a greatly reduced low frequency (VHF) reflection coefficient for the composite absorbing wall. The physical dimension and the material properties of each of the multiple backing layers are selected by a constrained nonlinear optimization data processing procedure or method. The optimization method utilizes known S parameters of the pyramid array, and either known properties of the backing layers, or constrained backing layer properties that are defined by the wall designer. Optimization is achieved by mathematically sampling the wall's wave reflection at wave frequencies and wave incident angles that are defined by the designer.

US Patent:

50161857, May 14, 1991

Filed:

Mar 24, 1989

Appl. No.:

7/328409

Inventors:

Edward F. Kuester - Boulder CO
Christopher L. Holloway - Boulder CO

Assignee:

University of Colorado Foundation, Inc. - Boulder CO

International Classification:

G06F 1560
E04B 182

US Classification:

364481

Abstract:

A pyramidal cone absorber structure is equated to an effective absorbing layer model having effective permittivity and permeability properties. A Riccati equation, governing the coefficient of reflection of the effective absorbing layer is derived. A computer program solves the Ricatti equation for the coefficient of reflection using initial values of complex permittivity. Iterative solutions are then obtained using increasing values of complex permittivity until no further reduction in the maximum coefficient of reflection over a specified frequency range is obtained, thus indicating optimum performance of the pyramidal cone absorber structure for a given set of cone dimensions. Optimization of the pyramidal cone absorber structure may also be optimized for a fixed set of complex permittivity values by varying the cone length and backing layer dimensions while maintaining the sum of those two dimensions constant.