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AssigneeLitton Systems, Inc.
InventorsPeter J. Conroy, Nathan D. Curry, Derek R. Warner
Estimating the term…
A direction finding antenna system includes a plurality of monopole elements disposed symmetrically around a center of a circular ground plane at the same radial distance from the center and a multimode combiner connected to the monopole elements to provide one or more mode outputs. A phase difference detector determines phase differences between selected ones of the mode outputs to provide azimuth bearing of a detected object. Typically, four or eight monopole elements are used. Placement of the inherently narrowband monopole elements in a bicone structure having a polarizer grid extends the useful bandwidth. Multiband coverage is achieved with a plurality of such antennas connected by a feed cable positioned on the polarizer grid to avoid interference.
An antenna system comprising:
An antenna system as recited in 3, wherein said phase reference is a second of said selected mode outputs.
An antenna system comprising:
An antenna system comprising:
An antenna system comprising:
A mode former receiving outputs from monopole antenna elements symetrically disposed on a groundplane, said mode former comprising at least three tandem couplers, a first of said tandem couplers being connected to receive an output from ones of said monopole elements disposed at about 0.degree. and 90.degree. and having an output connected to provide a signal to one of two inputs of a third of said tandem couplers, a second of said tandem couplers being connected to receive an output from ones of said monopole elements disposed at about 180.degree. and 270.degree. and having an output connected to provide a signal to a second of said inputs of said third tandem coupler said third tandem coupler having a terminal producing a mode +1 output.
Dependencies are inferred from the claim text.