Archimedes spiral array antenna

• US 6,525,697 B1
• Filed: 09/06/2001
• Issued: 02/25/2003
• Est. Priority Date: 07/11/2001
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Theobold, David
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US09/947,620
• Time in Patent Office: 537 Days
• Field of Search: H01/Q.136, H01/Q.138, 343/700.MS, 343/792.5, 343/795, 343/895
• US Class Current: 343/895
• CPC Class Codes: H01Q 1/36 Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 9/27 Spiral antennas

Abstract

A two-dimensional array design for an aperiodic array antenna. The design utilizes monopole or similar antenna elements that are arranged into the topology of an Archimedes spiral. The preferred spacing between radial arcs of the spiral is approximately one-half the desired wavelength. The preferred spacing between elements is also approximately one-half the desired wavelength

Claims

1. An array antenna comprising

a plurality of individually controlled radiating arrayed elements having nominally omnidirectional patterns in two dimensions, the elements suitably spaced with respect to one another and arranged along the path of an Archimedes spiral;

wherein the relative phase and amplitude of signals applied to each of the elements are controlled to obtain the desired radiation pattern from the combined action of all the elements.

2. The antenna of claim 1, wherein a first of the arrayed element is located at the center of the spiral.

3. The antenna of claim 1, wherein the distance between arcs is a fixed fraction of a wavelength on the order of one-half the wavelength.

4. The antenna of claim 3, wherein the distance between arrayed elements is a fixed fraction of a wavelength on the order of substantially one-half the wavelength.

5. The antenna of claim 1, wherein the distance between arrayed elements is a fixed fraction of a wavelength on the order of one-half the wavelength.

6. The antenna of claim 1, wherein the longitudinal axes of the arrayed elements are normal to a plane of the spiral.

7. The antenna of claim 1, wherein a conductor is connected to the end of the arrayed element that intersects a plane of the spiral.

8. The antenna of claim 1, wherein the arrayed element is a monopole.

9. The antenna of claim 1, wherein the arrayed element is a dipole.

10. The antenna of claim 1, wherein the arrayed element is a substantially omni-directional patch element.

11. The antenna of claim 1, wherein the spiral is defined by the equation R=kA, where k controls the spacing between adjacent arcs of the spiral, where R is the radial measure and A is the angular measure in a circular coordinate system;

the first element is located at position (R₀,A₀);

the element-to-element spacing is d=|(R_n,A_n)−

(R<sub>n−

1</sub>,A<sub>n−

1</sub>)|, for all elements n={0, 1, . . . , m−

1}, for an m-element array.

12. The antenna of claim 11, wherein the longitudinal axis of the arrayed elements is normal to the plane of the spiral.

13. The antenna of claim 11, wherein the distance between arcs is a fixed fraction of a wavelength on the order of one-half the wavelength.

14. The antenna of claim 11, wherein the distance between arrayed elements is a fixed fraction of a wavelength on the order of one-half the wavelength.

15. An array antenna comprising

a plurality of individually controlled radiating monopole elements, the elements suitably spaced with respect to one another and arranged along the path of an Archimedes spiral on a two dimensional planer surface,

wherein the spiral is defined by the equation R=kA, where k controls the spacing between adjacent arcs of the spiral, where R is the radial measure and A is the angular measure in a circular coordinate system;

a first element is located at position (R₀,A₀);

wherein the element-to-element spacing is d=|(R_n,A_n)−

(R<sub>n−

1</sub>,A<sub>n−

1</sub>)|, for all elements n={0, 1, . . . , m−

1}, for an m-element array, and the values for k and d are on the order of one-half a wavelength;

a feed for each element is located at the intersection of the element with the two-dimensional planer surface; and

wherein the relative phase and amplitude of signals applied to each of the elements are controlled to obtain the desired radiation pattern from the combined action of all the elements.

16. The array antenna of claim 15 wherein the m is at least six.

17. A method of making an array antenna, the method comprising the steps of:

(a) selecting the parameters for an Archimedes spiral;

(b) plotting the Archimedes spiral on a planer surface;

(c) selecting a quantity of individually controlled radiating arrayed elements having nominally omnidirectional patterns in two dimensions;

(d) plotting coordinates comprising the location of where the arrayed elements are to be mounted on the spiral, a first element being located at the center of the spiral and the elements being suitably spaced with respect to one another; and

(e) attaching each arrayed element so that one end of the element is attached to the planer surface at the plotted location;

wherein the relative phase and amplitude of signals applied to each of the elements are controlled to obtain the desired radiation pattern from the combined action of all the elements.

18. The method of claim 17, the selecting the parameters step further comprising spacing the arcs of the spiral a fixed fraction of a wavelength.

19. The method of claim 17, the plotting step further comprising spacing the arrayed elements a fixed fraction of a wavelength.

20. The method of claim 17, wherein fixed fraction of a wavelength for the arcs of the spiral is on the order of one-half the wavelength.

21. The method of claim 17, wherein fixed fraction of a wavelength for spacing the arrayed elements is on the order of one-half the wavelength.