Accession Number : AD0283687

Title :   ON INCREASING THE EFFECTIVE APERTURE OF ANTENNAS BY DATA PROCESSING

Corporate Author : ILLINOIS UNIV URBANA ELECTRICAL ENGINEERING RESEARCH LAB

Personal Author(s) : MACPHIE,ROBERT H.

Report Date : JUL 1962

Pagination or Media Count : 1

Abstract : DESCRIPTORS: *Antennas, *Antenna radiation patterns, Linear systems, Low pass filters, Radiofrequency filters, Voltage, Temperature, Equations, Integral transforms, Least square method, Polynomials, Theory, Measurement, Data processing systems. It was established that although a finite antenna acts as a perfect low pass filter of the spatial frequency spectrum of remote sources, it is theoretically possible to deduce the entire frequency spectrum from the output of the antenna. The spectrum is a band-limited analytic function, its values for the frequencies outside the pass band could be obtained by a process of analytic continuation of the function from within the band where it could be measured. It was shown that the process of expanding a function on a finite interval by an orthogonal Fourier series is not only very convenient but it is the only one of any practical value since the expansion of the non-orthogonal series is accompanied by the extreme error sensitivity described in Chapters 5 and 6 of this report. The similarity between this problem and that of a supergain antenna is noted. (Author)

Descriptors :   *ANTENNA RADIATION PATTERNS, *ANTENNAS, DATA PROCESSING, ELECTRIC POTENTIAL, EQUATIONS, INTEGRAL TRANSFORMS, LEAST SQUARES METHOD, LINEAR SYSTEMS, LOW PASS FILTERS, MEASUREMENT, POLYNOMIALS, RADIOFREQUENCY FILTERS, TEMPERATURE, THEORY

Distribution Statement : APPROVED FOR PUBLIC RELEASE