| 摘要 |
A parasitic antenna array (Yagi-Uda or loop type) for multiple frequency bands has its driven and parasitic elements interlaced on a single support boom. In a first aspect of the invention, series resonant circuits are located in one or more parasitic director elements in order to minimize the deleterious mutual coupling effect between directors of different frequency bands. In a second aspect of the invention, an inductance is placed across the feed point of the driven element of one or more non-selected frequency bands in order to minimize the bandwidth narrowing effect of closely-spaced driven elements and to provide a desired feed point impedance at the driven element of the selected frequency band. Although the two aspects of the invention may be used without one another, they are advantageously employed together. In addition, the second aspect of the invention may be applied to closely-spaced driven elements that are not part of a parasitic array.
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