EFFECT OF DIMENSION OF CONDUCTING BOX ON RADIATION-PATTERN OF A MONOPOLE ANTENNA FOR PORTABLE TELEPHONE

The relation between the radiation pattern and the dimension of the co nducting box for a portable telephone is illustrated both theoreticall y and experimentally. The Galerkin-moment method using the Fourier ser ies expansion for the surface current of the conducting box, which has a great advantage of having a high accuracy, is employed to obtain th e radiation pattern. As an example of antennas, a quarter-wavelength m onopole antenna having a sinusoidal current distribution is used. As a result, it is pointed out that the radiation pattern of a monopole an tenna mounted on the box tends to tilt in a lower direction both in th eory and in experiment as well. The relation between the radiation pat tern and the location of the monopole antenna is also described. An as ymmetrical, or distorted pattern is observed when the monopole antenna moves away from the center of the top plane.