Beam-steerable flat-panel reflector antenna

Many space applications require a high-gain antenna that can be easily deployable in space. Currently, the most common high-gain antenna for space-borne applications is an umbrella-type reflector antenna that can be folded while being lifted into Earth orbit. We propose a different type of high-gain antenna for easy space deployment. The proposed antenna is similar to reflector antennas except the curved main reflector is replaced by a flat reconfigurable surface for easy packing and deployment in space. A number of waveguides are placed on the flat surface so that the effective surface impedances at the waveguide openings are configured to give a focused beam. The length of each waveguide is adjusted so that, after the incident wave is reflected from the back conducting plate, the reflected wave has a phase at the open waveguide end such that the beam is focused in the predetermined direction. In other words, the law of reflection does not apply at the reconfigured surface. Also, beam steering can be achieved by adjusting the waveguide heights. Since the height of each waveguide is always less than a half of a wavelength, all the waveguide plates are relatively short. If the waveguide heights are controlled by an electronic means, an electronically beam-steerable antenna results.