Book Description

The feasibility of using physical optics approximation for computing radiation patterns of ground-based HF-VHF antennas in the presence of known ground irregularities is investigated. A computer program was written for physical optics formulation to evaluate the composite radiation patterns of a line source above an irregular, but deterministic, perfectly conducting surface. For the special case of a line source above a perfectly conducting plane with semicylindrical boss,the exact field expressions are derived, and the numerical results are compared with those obtained by physical optics for the same geometry. An error criterion that gives a meaningful error estimate at both the maxima and minima values of the radiation pattern is formulated and applied to the computed result. It is concluded that physical optics approximations can be used for predicting the radiation patterns of ground-based HF-VHF antennas.