Accession Number : AD0720599

Title :   Low-Frequency Loop Antenna Arrays, Part II.

Descriptive Note : Final technical rept., Jul 69-Sep 70,

Corporate Author : TECHNISCHE HOCHSCHULE GRAZ (AUSTRIA) INSTITUT FUER THEORETISCHE PHYSIK

Personal Author(s) : Ledinegg,Ernst

Report Date : DEC 1970

Pagination or Media Count : 134

Abstract : The report on Loop Antenna Arrays draws heavily on the previous report AD 693271, particularly for the formalae describing the loop array radiation field. Diagrams 1 to 53 give the radiation characteristics of horizontal arrays consisting of 50 or 100 single co-linear loops for various values of the ground conductivity, distance the current phase between two adjacent loops. For the high gain arrays of Diagrams 19 and 20 gain is increased by a factor equal to the square root of the number of loops. Part B contains an unified derivation and numerical evaluation of the resistance equivalent to the ground reaction as compared to the radiation resistance for both electric and magnetic dipole antennas. The question as to what extent a metallic disc on the ground below the antenna reduces the ground reaction on a vertical electric dipole was given an extensive theoretical treatment in Part C. Part D deals with the influence of perturbations on the far radiation field of an antenna array. Among the cases treated there is one where the perturbation is assumed as a strip where the soil has a conductivity different from that in the remaining domain. The electromagnetic field before and beyond the strip is calculated with the help of the reciprocity theorem. (Author)

Descriptors :   (*ANTENNA ARRAYS, LOOP ANTENNAS), ANTENNA RADIATION PATTERNS, NUMERICAL ANALYSIS, LOW FREQUENCY, AUSTRIA

Subject Categories : Electrical and Electronic Equipment

Distribution Statement : APPROVED FOR PUBLIC RELEASE