MICROSTRIP REFLECTARRAY FOR SATELLITE COMMUNICATION AND RADAR CROSS-SECTION ENHANCEMENT OR REDUCTION

摘要

A passive array of resonantly-dimensioned microstrip antenna radiator patches are closely spaced (i.e., less than one-tenth wavelength) above a ground plane and individually associated with transmission line segments terminated so as to cause the overall array to receive an incident r.f. electromagnetic field, to convert the received field into r. f. electrical currents which flow along the transmission lines and are absorbed by the terminations or reflected therefrom. In the latter case, the reflected r. f. energy is re-transmitted in a predetermined direction as a re-directed r.f. electromagnetic field. The presently preferred embodiment is a relatively thin, flexible and thus conformable layered structure formed by selectively etching conductive material from one side of a metallically cladded dielectric sheet. For satellite communication, a flat reflectarray may be associated with a primary r.f. transmitter/receiver structure disposed at a focal area or spot of the reflectarray having an appropriately phased aperture (e.g., parabolic). For radar cross-section enhancement or reduction, the reflectarray aperture is phased so as to retro-reflect incident r.f. fields or so as to scatter, otherwise misdirect or absorb (e.g., by using lossy resistive transmission line terminations) the incident r.f. field.