Connected arrays of dipoles for broad band, wide angle scanning, dual polarized applications : a novel solution to the common mode problem

Wideband connected arrays of dipoles are a very promising solution for broadband, wide-angle scanning phased arrays. Unlike tapered slot antennas, connected arrays can operate over wide bandwidth maintaining polarization purity. However, an open issue for the practical implementation of these arrays is the propagation of common-mode currents along the differential feeding lines. A solution for this problem is here proposed and is constituted by a loop-shaped transformer that acts as common-mode rejection circuit. Simulated results are presented for connected arrays of dipoles for both linear and dual polarization, with 30% relative bandwidth (from 10.7 to 14.5 GHz) and scanning capability up to 45° for any azimuth