| 摘要 |
<p>A frequency selective reflector is provided for use in an electromagnetic antenna system, wherein the frequency selective reflector reflects electromagnetic waves having two or more frequencies. The reflector includes an inner portion which has a reflective surface which will reflect at least first and second frequencies. The reflector also includes an outer portion which will reflect electromagnetic waves having the first frequency in substantially the same direction as electromagnetic waves of the first frequency reflected from the inner portion. On the other hand, the outer portion is constructed to prevent the constructive reflection of electromagnetic waves of the second frequency in the same direction as electromagnetic waves of the second frequency reflected from the inner portion. By setting the diameter between the inner and outer circuit portions to have a predetermined relationship to one another, the reflector's electrical size in terms of wavelength can be substantially equalized for the first and second frequencies so that the beam width of the radiation patterns for the first and second frequencies will be superimposed and substantially equal to one another. <IMAGE> <IMAGE></p> |
