Log-periodic longitudinal slot antenna array excited by a waveguide with a conductive ridge

Claim 1

A broadband antenna comprising a closed electrically conductive TE-mode ridged waveguide linearly longitudinally tapered between a first end having a maximum cross-sectional dimension and a second end having a minimum cross-sectional dimension, said waveguide having a first wall from which a conductive ridge projects and a second wall opposite said first wall and being adapted to longitudinally propagate TE-mode electromagnetic waves having a transverse electric (E) field vector, a transverse magnetic (H T ) field vector component orthogonal to said E-field vector and a longitudinal magnetic (H L ) field vector with the E-field vector normal to said first and second walls, said waveguide having orthogonal central E and H planes parallel to said E-field and to said transverse H T -field components, respectively, at least one of said walls having a plurality of longitudinally spaced slots formed with both the spacing between longitudinally adjacent slots and the slot dimensions decreasing in increments of a predetermined ratio from said first end of the waveguide to said second end, each of said slots being longitudinally elongated substantially in the direction of wave propagation, and energy feed means connected to at least one of said ends of said waveguide whereby the energy radiation pattern is a beam boresighted transversely of the slotted wall.