Patent ID: 7301508

Claim:
A mechanism for varying the focal length of an aperture type transmitting antenna having an operating frequency in the microwave band capable of being illuminated externally or internally and of emitting a phase front to form a beam and having a fixed aperture outer rim, the mechanism comprised of: a. a first flexible microwave antenna aperture plate of equivalent aperture diameter D fixed to said fixed aperture outer rim; b. a second microwave antenna plate of equivalent aperture diameter of approximately D/√2 adjacent, parallel to, and centered on said first aperture plate; c. a plurality of transducers placed near the outer edge of said second plate, connecting said first and second plate, and capable of linearly displacing said first plate with respect to said second plate; d. a frame connected to a fixed outer rim of said second plate and to said first plate outer rim, thereby fixing said second plate's position with respect to said first plate; and e. means for commanding the displacement of said transducers to change the displacement between said first and second plates, thereby altering the curvature of said first plate to control the transmitted beam shape, direction, and power density in the Fresnel zone.