Dielectric lens focused scanning beam antenna for satellite communication system

• US 5,548,294 A
• Filed: 08/17/1994
• Issued: 08/20/1996
• Est. Priority Date: 08/17/1994
• Status: Expired due to Term

• Current Assignee: Wengen Wireless LLC (Intellectual Ventures LLC)
• Original Assignee: Teledesic, LLC (Michael J. Larson, MBA)
• Inventors: Sturza, Mark A.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): PHAN, DAO LINDA
• Application Number:
  US08/292,148
• Time in Patent Office: 734 Days
• Field of Search: 342/354, 342/352, 342/372, 455/12.1, 455/13.1
• US Class Current: 342/372
• CPC Class Codes: H01Q 1/288 Satellite antennas
• CPC Class Codes: H01Q 15/02 Refracting or diffracting devices, e.g. lens, prism
• CPC Class Codes: H01Q 25/008 lens fed multibeam arrays
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H04B 7/2041 Spot beam multiple access

Abstract

A method and apparatus for providing a plurality of beams (30) transmitted and received from positions in low Earth orbit (11) for communicating directly with a plurality of portable, mobile and fixed terminals and gateways is disclosed. A plurality of scanning beam antennas (28) is deployed on each satellite (12) within a constellation (10) of satellites placed in low Earth orbit (11). Each one of said plurality of scanning beam antennas (28) simultaneously receives and transmits a plurality of beams (30), each of which beams (30) illuminates cell (26) in an Earth-fixed grid (20). The beams (30) are formed by each scanning beam antenna (28) and are focused on the cell (26) by a dielectric lens (60). A preferred embodiment uses a Luneberg spherical lens (60). Each beam (30) is electronically shaped and steered to keep the cell (26) of the Earth-fixed grid (20) within the beam footprint (50).

Claims

1. A method for providing a plurality of beams transmitted and received from positions in Earth orbit, for communicating directly with a plurality of portable, mobile and fixed terminals and gateways comprising the steps of:

orbiting a constellation of satellites (10) in low Earth orbit (11);

creating an Earth-fixed grid (20) defining a plurality of Earth-fixed supercells (22);

said plurality of Earth-fixed supercells (22) including a plurality of Earth-fixed cells (26);

deploying a plurality of scanning beam antennas (28) on each satellite (12) within said constellation (10) of satellites;

simultaneously receiving a plurality of beams (30) with one of said plurality of scanning beam antennas (28) and simultaneously transmitting a plurality of beams (30) with another of said plurality of said scanning beam antennas (28) and simultaneously receiving and transmitting a plurality of beams (30) with another one of said plurality of scanning beam antennas (28);

said beams (30) having a footprint (50) on the surface of the Earth (E);

forming said plurality of beams (30) with each of said plurality of scanning beam antennas (28) and continuously illuminating said plurality of Earth-fixed cells (26) by focusing said plurality of beams (30) on each said cell (26) with a spherically-shaped dielectric lens (60);

electronically shaping and steering each one of said plurality of beams (30) by amplitude weighting an antenna feed element (63,

     82) at a nominal beam center position and a plurality of said antenna feed elements (63,82) at adjacent positions to keep each of said plurality of Earth-fixed cells (26) of said Earth-fixed grid (20) within said footprint (50) of each of a corresponding one of said plurality of beams (30) as said satellite (12) progresses along its said low Earth orbit (11); and

communicating with said terminals and gateways in each of said plurality of Earth-fixed cells (26) with signals carried on said plurality of beams (30), each of said plurality of beams (30) operating at one of nine frequencies (F₁ -F₉), said nine frequencies (F₁ -F₉) being reused one-hundred percent for communications in each one of said plurality of supercells (22).