Dual band phased array employing spatial second harmonics

A directive antenna operable in multiple frequency bands includes an active antenna element and at least one passive antenna element parasitically coupled to the active antenna element. The passive antenna element(s) have length and spacing substantially optimized to operate at (i) a fundamental frequency associated with the active antenna element and (ii) a higher resonant frequency related to the fundamental frequency. Spatial-harmonic current-distributions of the passive antenna elements are used to create the multiple frequency bands of operation. The directive antenna also includes devices operatively coupled to the passive antenna element(s) to steer an antenna beam formed by applying a signal at the fundamental resonant frequency, higher resonant frequency, or both to the active antenna element to operate in the multiple frequency bands.