HF Antenna Optimization Study
Final technical rept. Oct 1966-Oct 1968
SYLVANIA ELECTRONIC SYSTEMS-WEST MOUNTAIN VIEW CA
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The report presents a summation of a study to determine the optimum log periodic dipole array design for a high gain, low coverage HF antenna over real andor ground screen covered earth. The major problem encountered is one of determining antenna electrical characteristics accurately in free space and in a real earth environment. The present state of the art in analytical antenna design does not allow the engineer to predict log periodic antenna electrical characteristics, especially over real earth, with sufficient accuracy to be valuable for strict system requirements. To solve this problem, a mathematical model of a log periodic antenna is set up and solved with the use of high speed digital computers. The model used allows one to obtain the current distribution on the antenna knowing only its physical dimensions and something about the conductivity of the material used in its construction. The theoretical model, which treats the antenna as a boundary value problem, automatically includes all the interactions or mutual coupling between elements. From the computed values of the currents on the antenna all electrical characteristics of the antenna, such as radiation patterns, absolute gain, and input impedance are calculated. Theoretical and measured UHF radiation patterns and gains are compared for evaluation of the technique. Free space and real earth calculations are presented and an optimum antenna design is chosen from this information.
- Electrical and Electronic Equipment