Accession Number : AD0455624


Title :   A STUDY OF SUPERGAIN ARRAYS.


Descriptive Note : Final rept.,


Corporate Author : EDO CORP COLLEGE POINT NY


Personal Author(s) : Winder, Alan


Report Date : 07 Jan 1965


Pagination or Media Count : 1


Abstract : A supergain array is one designed for maximum directivity index (MDI). For a linear array of N point elements spaced equally at integral halfwavelengths, with uniform in-phase excitation, the MDI equals 10 log N. For element spacings less than one-half wavelength, MDI requires outof-phase excitation and a relatively large range of amplitudes which must be controlled with extreme accuracy. The aplitude shading required for MDI in wide-band reception may be determined by considering the space noise correlation function. The presence of self-noise in the individual elements of an array or their preamplifiers may seriously reduce the effective gain of the array designed for MDI. This degradation of performance is particularly enhanced if the amplitude shading of any of the elements is considerably larger than the overall value required for uniform shading. The synthesis problem for realizing supergain is discussed. Finally, the noise figure of a piezoelectric hydrophone-cableamplifier circuit and the source impedance required to minimize it, is calculated. (Author)


Descriptors :   *PIEZOELECTRIC TRANSDUCERS , GAIN , BROADBAND , BANDWIDTH , NOISE(RADIO) , MATHEMATICAL ANALYSIS , CORRELATION TECHNIQUES , CAPACITANCE , ELECTRIC CABLES , PREAMPLIFIERS , EXTREMELY LOW FREQUENCY


Distribution Statement : APPROVED FOR PUBLIC RELEASE