Patent ID: 6154180
Filing Date: 2000-11-28
Classification: H01Q

Abstract:
A parasitic antenna array for at least two frequency bands, comprisingone or more driven elements for said at least two frequency bands,separate parasitic elements for each of said at least two frequency bands, each of said separate parasitic elements operative as a director on one of said at least two frequency bands, respectively, at least the parasitic element or elements for the frequency band or bands other than the highest frequency band having at least one series resonant circuit in each half of the respective parasitic element when the parasitic element is a yagi element and including a series resonant circuit in each quarter of the parasitic element when the parasitic element is a loop element, the resonant circuit having a resonant frequency substantially in the frequency band in which the respective parasitic element functions as a director, thereby acting as a short circuit in said frequency band and as an open circuit in the other frequency band or bands, the series resonant circuits being located at positions substantially symmetrically spaced along the element such that for the frequency band or frequency bands other than the frequency band in which the parasitic element functions as a director, the parasitic element is electrically broken into portions that reduce the effect of the parasitic element on the radiation pattern of the antenna array in said other frequency band or bands.