Electronically Scanned Arrays (ESAs) and K-Space Gain Formulation

Electronically Scanned Arrays (ESAs) and K-Space Gain Formulation
Author: Roger A. Dana
Publisher: Springer
Total Pages: 114
Release: 2019-02-14
Genre: Technology & Engineering
ISBN: 3030046788

This book fills in details that are often left out of modern books on the theory of antennas. The starting point is a discussion of some general principles that apply to all electronic systems and to antennas in particular. Just as time domain functions can be expanded in terms of sine waves using Fourier transforms, spatial domain functions can be expanded in terms of plane waves also using Fourier transforms, and K-space gain is the spatial Fourier transform of the aperture weighting function. Other topics discussed include the Discrete Fourier Transform (DFT) formulation of antenna gain and what is missing in this formulation, the effect of sky temperature on the often specified G/T ratio of antennas, sidelobe control using conventional and novel techniques, and ESA digital beamforming versus adaptive processing to limit interference. Presents content the author derived when first asked to evaluate the performance of an electronically scanned array under design with manufacturing imperfections and design limitations; Enables readers to understand the firm theoretical foundation of antenna gain even when they must start from well-known formulations rather than first principles; Explains in a straightforward manner the relationship between antenna gain and aperture area; Discusses the relationship between sidelobe control algorithms and aperture shape, how to take advantage of it, and what the penalties are; Shows the equivalence of Minimum-Variance, Distortionless Response (MVDR) and Space-Time Adaptive Processing (STAP) and how these algorithms can be used with ESA subarrays to mitigate interference.

Electronically Scanned Arrays (ESAs) and K-space Gain Formulation

Electronically Scanned Arrays (ESAs) and K-space Gain Formulation
Author: Roger A. Dana
Publisher:
Total Pages:
Release: 2019
Genre: TECHNOLOGY & ENGINEERING
ISBN: 9783030046798

This book fills in details that are often left out of modern books on the theory of antennas. The starting point is a discussion of some general principles that apply to all electronic systems and to antennas in particular. Just as time domain functions can be expanded in terms of sine waves using Fourier transforms, spatial domain functions can be expanded in terms of plane waves also using Fourier transforms, and K-space gain is the spatial Fourier transform of the aperture weighting function. Other topics discussed include the Discrete Fourier Transform (DFT) formulation of antenna gain and what is missing in this formulation, the effect of sky temperature on the often specified G/T ratio of antennas, sidelobe control using conventional and novel techniques, and ESA digital beamforming versus adaptive processing to limit interference. Presents content the author derived when first asked to evaluate the performance of an electronically scanned array under design with manufacturing imperfections and design limitations; Enables readers to understand the firm theoretical foundation of antenna gain even when they must start from well-known formulations rather than first principles; Explains in a straightforward manner the relationship between antenna gain and aperture area; Discusses the relationship between sidelobe control algorithms and aperture shape, how to take advantage of it, and what the penalties are; Shows the equivalence of Minimum-Variance, Distortionless Response (MVDR) and Space-Time Adaptive Processing (STAP) and how these algorithms can be used with ESA subarrays to mitigate interference.

Electronically Scanned Arrays MATLAB® Modeling and Simulation

Electronically Scanned Arrays MATLAB® Modeling and Simulation
Author: Arik D. Brown
Publisher: CRC Press
Total Pages: 232
Release: 2017-12-19
Genre: Technology & Engineering
ISBN: 1439861641

"[Contains] more lengthy mathematical derivations than most {comparable books] ... for arrays, provides for a unique, stand-alone mathematical description that can be adopted by anyone trying to communicate the theoretical foundation for their array design...has insights from a practitioner that are unique. The MATLAB® scripts alone are worth the price." —Daniel C. Ross, Ph. D, Northrop Grumman Corporation Electronically Scanned Arrays: MATLAB® Modeling and Simulation is considered the first book to provide comprehensive modeling/simulation programs used to design and analyze Electronically Scanned Arrays (ESA), a key technology internationally in the scientific and engineering communities. Several books have been written about ESAs, but most cover only fundamental theory. Few, if any, provide the insightful, easy-to-use simulation tools found in this book. Obviously, MATLAB® is one of the greatest tools available for exploring and understanding science and engineering concepts, and we use MATLAB functions to easily and instantly calculate ESA patterns. However, to achieve a truly insightful and in-depth analysis of subarray architectures, conformal arrays, etc., it is imperative that users first develop a firm grasp of ESA fundamentals. Covers largely unexplored topics, such as reliability aspects and the application of ESAs in space This volume helps readers build that elemental understanding of how ESAs work. It also provides code to run as an aid, so that readers don’t have to start from scratch. The book expands on ESA principles and provides a modeling framework, using MATLAB to model applications of ESAs (i.e. pattern optimization, space-based applications, and reliability analysis). Presented code serves as an excellent vehicle to help readers master the analysis and simulation of ESAs. Exploring how difficult problems can be simplified with short, elegant solutions, this is an invaluable resource for students and others new to ESAs, as well as experienced practicing engineers who model ESAs at the systems level.

Principles of Modern Radar

Principles of Modern Radar
Author: Mark A. Richards
Publisher: SciTech Publishing
Total Pages: 0
Release: 2023-02-17
Genre: Technology & Engineering
ISBN: 9781839533815

Principles of Modern Radar: Basic Principles is a comprehensive text for courses in radar systems and technology, a professional training textbook for formal in-house courses and for new hires; a reference for ongoing study following a radar short course and a self-study and professional reference book.

NASA SP.

NASA SP.
Author:
Publisher:
Total Pages: 350
Release: 1962
Genre: Aeronautics
ISBN:

Use of Services for Family Planning and Infertility, United States, 1982

Use of Services for Family Planning and Infertility, United States, 1982
Author: Gerry E. Hendershot
Publisher:
Total Pages: 982
Release: 1988
Genre: Birth control
ISBN: 9780840602220

The 1982 statistics on the use of family planning and infertility services presented in this report are preliminary results from Cycle III of the National Survey of Family Growth (NSFG), conducted by the National Center for Health Statistics. Data were collected through personal interviews with a multistage area probability sample of 7969 women aged 15-44. A detailed series of questions was asked to obtain relatively complete estimates of the extent and type of family planning services received. Statistics on family planning services are limited to women who were able to conceive 3 years before the interview date. Overall, 79% of currently mrried nonsterile women reported using some type of family planning service during the previous 3 years. There were no statistically significant differences between white (79%), black (75%) or Hispanic (77%) wives, or between the 2 income groups. The 1982 survey questions were more comprehensive than those of earlier cycles of the survey. The annual rate of visits for family planning services in 1982 was 1077 visits /1000 women. Teenagers had the highest annual visit rate (1581/1000) of any age group for all sources of family planning services combined. Visit rates declined sharply with age from 1447 at ages 15-24 to 479 at ages 35-44. Similar declines with age also were found in the visit rates for white and black women separately. Nevertheless, the annual visit rate for black women (1334/1000) was significantly higher than that for white women (1033). The highest overall visit rate was for black women 15-19 years of age (1867/1000). Nearly 2/3 of all family planning visits were to private medical sources. Teenagers of all races had higher family planning service visit rates to clinics than to private medical sources, as did black women age 15-24. White women age 20 and older had higher visit rates to private medical services than to clinics. Never married women had higher visit rates to clinics than currently or formerly married women. Data were also collected in 1982 on use of medical services for infertility by women who had difficulty in conceiving or carrying a pregnancy to term. About 1 million ever married women had 1 or more infertility visits in the 12 months before the interview. During the 3 years before interview, about 1.9 million women had infertility visits. For all ever married women, as well as for white and black women separately, infertility services were more likely to be secured from private medical sources than from clinics. The survey design, reliability of the estimates and the terms used are explained in the technical notes.