Accession Number : AD0693271

Title :   LOW-FREQUENCY LOOP ANTENNA ARRAYS.

Descriptive Note : Final technical rept.,

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

Personal Author(s) : Ledinegg,Ernst

Report Date : JUL 1969

Pagination or Media Count : 113

Abstract : The present report treats the radiation properties of loop antenna systems which are situated above the ground and are centrally excited by a source of current. The current reaction due to the earth, the mutual induction and the radiation reaction are taken into account. The theory considers two loop-systems, viz., 'the horizontal loop-system' and the 'vertical loop-system' where the surface normal of the loops is vertical and parallel to the earth, respectively. For both systems explicit formulae are derived which contain a number of typical geometrical and physical parameters. The work is divided into three main sections. Sections A and B deal with the theory of the current reaction of the ground for horizontal and vertical loop-antennas where the influence of the earth is described by a resistance induced into the loop. Further, the calculation of the mutual influence between the loops of the system is performed which is also to be characterized by resistance coefficients. Section C is directed to the calculation of the radiation fields for both systems and is performed on the basis of the antenna currents presented in sections A and B. The explicit representation of the radiation fields is effected by a systematic application of the saddlepoint method of first and second order with which the occurring Sommerfeld integrals are evaluated. In this context it has been shown that the radiation field for special loop-antenna systems near the ground can be calculated rigorously. (Author)

Descriptors :   (*RADIO TRANSMISSION, LOOP ANTENNAS), (*LOOP ANTENNAS, LOW FREQUENCY), ANTENNA ARRAYS, ANTENNA RADIATION PATTERNS, ELECTROMAGNETIC FIELDS, MATHEMATICAL ANALYSIS, DIPOLE MOMENTS, STEEPEST DESCENT METHOD, LOW FREQUENCY

Subject Categories : Electrical and Electronic Equipment
      Radio Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE