Control of Electromagnetic Scattering by Antenna Impedance Loading

Control of Electromagnetic Scattering by Antenna Impedance Loading
Author: Shi-chuan Lee
Publisher:
Total Pages: 88
Release: 1974
Genre: Electromagnetic waves
ISBN:
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The application of impedance loading techniques for the reduction of backscatter from radar targets were studied. The hybrid methods which combine the GTD and the moment method were used to analyze the backscattering from various geometries such as impedance loaded infinite wedge and a two-dimensional wing model. The effect of both the trailing and the leading edge was considered by using a two-dimensional wing model. The edge diffraction source can be considerably reduced over a 3:1 frequency band for the two-dimensional case. The square plate with a loaded slot was analyzed by a wire grid model. The backscatter reduction of the square plate can be achieved at least over a 2:1 frequency band.

Control of Electromagnetic Scattering from Wing Profiles by Impedance Loading

Control of Electromagnetic Scattering from Wing Profiles by Impedance Loading
Author: J. A. Aas
Publisher:
Total Pages: 108
Release: 1975
Genre: Electromagnetic waves
ISBN:
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A computational technique has been developed to calculate the electromagnetic scattering from two-dimensional wing profiles loaded by impedance strips. These strips are represented by impedance boundary conditions. This report deals with the parallel electric polarization (TM polarization) while a similar study of the perpendicular polarization is contained in Reference (1). The effect of the impedance loading is studied for different shapes and sizes of the wing, and for different angles of incidence. The last part of the report deals with the relation between two- and three-dimensional scattering. Three-dimensional problems may in certain cases be solved at least approximately from the knowledge of the scattered field in two-dimensional problems. (Author).

Active Radar Cross Section Reduction

Active Radar Cross Section Reduction
Author: Hema Singh
Publisher: Cambridge University Press
Total Pages: 354
Release: 2015-03-02
Genre: History
ISBN: 1107092612
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This book discusses the active and passive radar cross section (RCS) estimation and techniques to examine the low observable aerospace platforms. It begins with the fundamentals of RCS, followed by the dielectric, magnetic and metamaterials parameters of the constituent materials and then explains various methods and the emerging trends followed in this area of study. The RCS estimation of phased array including the mutual coupling effect is also presented in detail in the book. The active RCS reduction is carefully touched upon through the performance of phased arrays, sidelobe cancellers and mitigation of multipath effect. Providing information on various adaptive algorithms like least mean square (LMS), recursive least square (RLS) and weighted least square algorithms, the authors also mention the recent developments in the area of embedded antennas, conformal load bearing antenna, metamaterials and frequency selective surface (FSS) based RCS reduction.

Continuation of the Investigation of Multi-frequency Radar Reflectivity and Radar Target Identification

Continuation of the Investigation of Multi-frequency Radar Reflectivity and Radar Target Identification
Author: D. L. Moffatt
Publisher:
Total Pages: 38
Release: 1975
Genre: Airplanes
ISBN:
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This report summarizes research during the period July 1, 1974 to June 30, 1975 under the contract on two technical objectives of the Air Force: improved detection and discrimination of radar targets and reduction of nonspecular scattering by wing geometries. The report is contained in two main sections. The first section outlines methods for deducing the complex natural resonances of arbitrary radar targets and the use of these resonances via predictor-correlator processing for detection and discrimination. Illustrative examples of both natural resonance extraction and discrimination are given for aircraft targets. The second section of the report summarizes the analysis of a loaded two-dimensional wind model for horizontal polarization. Hybrid techniques combining moment methods and the geometrical theory of diffraction are used and the loading consists of surface impedance patches. Examples of reduction of the nonspecular cross section are given. A 'folded dipole' like antenna is used as an alternate mechanism for controlling edge diffracted fields.