There is disclosed an antenna exhibiting resonance over a broad frequency band or over a plurality of closely-spaced frequency bands, comprising a ground plane, a non-driven element affixed substantially perpendicular to the ground plane, a driven element affixed substantially perpendicular to the ground plane and a horizontal conductor electrically connected between the driven and the non-driven elements and disposed substantially parallel to the ground plane. The non-driven and the driven elements further comprise periodic slow wave structures. The periodic slow wave structures are configured to provide a substantially constant propagation factor with respect to the applied signal frequency, such that the antenna exhibits broad resonance characteristics.