Low cost beam steering planar array antenna

• US 6,184,827 B1
• Filed: 02/26/1999
• Issued: 02/06/2001
• Est. Priority Date: 02/26/1999
• Status: Expired due to Term

• Current Assignee: CDC Propriete Intellectuelle
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Munger, Archer David, Dendy, Deborah Sue, Ma, Stephen Chih-hung, Warble, Keith Vaclav, Corman, David Warren
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US09/258,231
• Time in Patent Office: 711 Days
• Field of Search: 342/367-377
• US Class Current: 342/372
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H01Q 3/36 with variable phase-shifters

Abstract

A planar array antenna for use with an earth-based subscriber unit generates receive or transmit communications beams through the use of digital beamforming networks (210, 211) which provide beam steering in a first dimension. In another dimension, the communications beams are synthesized by way of a waveguide structure (300, FIG. 3) which is repeated for each row of the antenna array. The waveguide outputs are weighted due to the positioning of coupling slots (350) or coupling probes (450) which transfer carrier signals to and from each waveguide. The slots or coupling probes from the waveguides are coupled to a group of barium strontium titanate (BST) (360, FIG. 3) or micro-electromechanical systems (MEMS) switch (460, FIG. 4) phase shift elements which are under the control of a control network (221, 222, FIG. 2). The resulting signals are radiated by the antenna elements of the planar antenna array (310, FIG. 3) to form a communications beam.

Claims

1. An antenna for generating a communications beam which is steerable in a first and second dimension, said antenna comprising:

a digital beamforming network configured to create a beam that is steerable in said first dimension;

a plurality of barium strontium titanate phase shift elements coupled to said digital beamforming network and each of said plurality of barium strontium titanate phase shift elements coupled to one of a plurality of radiating elements; and

a control network coupled to each of the plurality of barium strontium titanate phase shift elements, the control network configured to control an amount of phase shift of each of the plurality of barium strontium titanate phase shift elements in order to steer the communications beam in a second dimension.

2. The antenna of claim 1, wherein the control network supplies an analog voltage to the plurality of barium strontium titanate phase shift elements in order to steer the communications beam in the second dimension.

3. The antenna of claim 1, wherein each of the plurality of barium strontium titanate phase shift elements comprises a microstrip phase shifter, which includes at least one micro-electromechanical systems (MEMS) switch.

4. The antenna of claim 3, wherein the control network supplies a discrete voltage to the at least one MEMS switch in order to steer the communications beam in the second dimension.

5. The antenna of claim 1, wherein the antenna is included in a subscriber unit which communicates with an orbiting satellite communications node.

6. The antenna of claim 5, wherein the antenna further comprises an interface to a processor which controls steering of the communications beam in order to maintain a communications link with an orbiting satellite communications node.

7. The antenna of claim 1, wherein said digital beamforming network is adapted to receive communications beams.

8. An system for generating a communications beam which is steerable in one dimension, comprising:

a distributing element for distributing carrier signals, said distributing element comprising a waveguide having coupling slots, which are cut into a wall of said waveguide;

a plurality of barium strontium titanate phase shift elements coupled to said distributing element;

a control network coupled to said plurality of barium strontium titanate phase shift elements, said control network supplying a voltage which controls an amount of phase shift applied to said carrier signals; and

a plurality of antenna elements for radiating said carrier signals.

9. The system of claim 8, wherein said plurality of barium strontium titanate phase shift elements comprise a MEMS switch.

10. The system of claim 8, wherein said distributing element comprises a waveguide having coupling probes inserted into a wall of said waveguide.