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An antenna element is comprised of two rectangular microstrip patch dipoles spaced by dielectric a predetermined distance above a ground plane conductor. One edge of each dipole is electrically shunted to the ground plane conductor. The dipole feedpoints are separated by a quarter wavelength of the

An antenna element is comprised of two rectangular microstrip patch dipoles spaced by dielectric a predetermined distance above a ground plane conductor. One edge of each dipole is electrically shunted to the ground plane conductor. The dipole feedpoints are separated by a quarter wavelength of the antenna resonant frequency. An isolated power splitter and phase shifter connects an antenna element port with the dipole feedpoints so that the signal at one feedpoint lags the signal at the other feedpoint by 90°. The antenna element will end fire through the dipoles in the direction of the lagging signal feedpoint. A low profile circular array antenna is comprised of eight such antenna elements arranged on the ground plane conductor equally spaced with their phase centers on a common phase center circle.

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A low profile circular array antenna resonant at a design frequency comprising: a ground plane conductor; a plurality of N antenna elements, each comprised of at least two patch dipoles, each said dipole being comprised of a flat rectangular conductive plate arranged parallel to said ground plane co

A low profile circular array antenna resonant at a design frequency comprising: a ground plane conductor; a plurality of N antenna elements, each comprised of at least two patch dipoles, each said dipole being comprised of a flat rectangular conductive plate arranged parallel to said ground plane conductor and spaced a predetermined distance which is less than a quarter wavelength of said design frequency above said ground plane conductor and electrically shunted along at least one edge of said plate to said ground plane, the dipoles comprising an antenna element being arranged on a radial line from a common center on said ground plane conductor, there being N equally spaced radial lines from said common center, one said line for each said antenna element, each said plate having a feedpoint, the feedpoints on the dipoles comprising an antenna element being separated along said line a predetermined distance equivalent to a phase shift of said design frequency; a plurality of N isolated power splitter means, one for each antenna element, having at least first, second and third ports, the power at said first port being split to said second and third ports, and including means for electrically isolating said second and third ports and additionally including first means for connecting said second port to the feedpoint of one of said dipoles of the associated antenna element and second means for connecting said third port to the feedpoint of the other of said dipoles of the same associated antenna element, each said power splitter means including means for shifting the phase of a signal of said design frequency at the feedpoint of said one dipole with respect to the signal of said design frequency at the feedpoint of said other of said dipoles by a phase angle equivalent to said predetermined distance.