A dual-band antenna is provided that combines two normally disparate communications
modes into a single compact aperture minimizing overall
mass and volume, while maintaining high
performance efficiency and reciprocity of each individual mode. The antenna is compatible with both optical (near-IR / visible) and RF (
microwave /
millimeter-wave)
transceiver subsystems for
high bandwidth communications, applicable primarily to long- to extremely long-range (space-to-ground) link distances. The
optical link provides
high bandwidth while the RF provides a lower data-rate weather
backup,
accommodation for traditional navigation techniques, and assistance in cueing the extremely tight
optical beam by matching the RF
beamwidth to an optical fine-steering mechanism field-of-regard. The configuration is built around a near-
diffraction-limited high performance
primary mirror shared by both a direct-fed RF
antenna design and a Cassegrain
optical telescope. Material properties are exploited to combine the optical
secondary mirror with the RF feed structure, providing a collimated
optical beam interface at the antenna vertex.