Common-mode resonances in ultra wide band connected arrays of dipoles: Measurements from the demonstrator and exit strategy

A 6-9 GHz prototype array of dual-polarized connected dipoles has been manufactured. The array is composed by two orthogonal sets of 8 times 8 elements for each polarization (128), arranged in an egg-crate configuration. Preliminary measurements highlighted the presence of unpredicted common-mode resonances excited in the vertical feeding lines. An analysis of the common-mode excitation is carried out and exit strategies for a design of a resonance-free connected array are presented.