Electrically end coupled parasitic microstrip antennas

Claim 1

An electrically end coupled parasitic microstrip antenna for providing high gain in the end fire mode, comprising: a. a thin ground plane conductor; b. a driven microstrip radiating element having a feedpoint thereon; c. said driven radiating element being fed from a microwave transmission line at said feedpoint; d. at least one parasitic microstrip radiating element being spaced apart from one end of said driven radiating element in an end-to-end arrangement; e. said driven microstrip radiating element and said at least one parasitic microstrip radiating element being equally spaced apart from said ground plane and separated from said ground plane by a dielectric substrate; f. said driven microstrip radiating element being electrically coupled end-to-end to said at least one parasitic microstrip radiating element by the electric field generated in said driven element when excited to radiate by energy fed to said feedpoint; both said driven element and said at least one parasitic element being excited to radiate, the energy in the end fire direction adding between the end-to-end coupled microstrip elements to provide high gain; g. the antenna radiation pattern being determined by the phase relationship and amplitude distribution between said excited driven element and said at least one parasitic element, the phase relationship and amplitude distribution being governed by the end-to-end separation between the driven element and said at least one parasitic element and the length of said at least one parasitic element; the mutual coupling impedance and the input impedance of the driven element which together form the antenna impedance also being governed by the end-to-end separation between the driven element and said at least one parasitic element.