An interleaved array of electronically steerable antennas is capable of simultaneously operating and/or independently beam scanning at different frequencies from a single aperture. An antenna system may comprise a plurality of electronically steerable antennas configured to be operable at different frequencies, each of the antennas comprising a feed launching a surface wave and surface-wave waveguides connected to the feed. The surface-wave waveguides of the antennas operable at different frequencies may be interleaved with each other.