Circularly symmetric, zero redundancy, planar array having broad frequency range applications

• US 6,205,224 B1
• Filed: 05/17/1996
• Issued: 03/20/2001
• Est. Priority Date: 05/17/1996
• Status: Expired due to Term

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Underbrink, James R.
• Primary Examiner(s): Chang, Vivian
• Application Number:
  US08/652,629
• Time in Patent Office: 1,768 Days
• Field of Search: 381/92, 367/118, 367/119, 367/122, 367/123, 367/905, 367/126, 343/895, 343/844, 343/893
• US Class Current: 381/92
• CPC Class Codes: G10K 11/34 using electrical steering of transducer arrays, e.g. beam steering constructional aspects B06B1/0607, B06B1/085
• CPC Class Codes: H01Q 21/061 Two dimensional planar arrays
• CPC Class Codes: H01Q 21/22 Antenna units of the array energised non-uniformly in amplitude or phase, e.g. tapered array or binomial array
• 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: H04R 1/403 loud-speakers
• CPC Class Codes: H04R 2201/401 2D or 3D arrays of transducers
• CPC Class Codes: H04R 2201/405 Non-uniform arrays of transducers or a plurality of uniform arrays with different transducer spacing
• CPC Class Codes: H04R 2430/20 Processing of the output signals of the acoustic transducers of an array for obtaining a desired directivity characteristic H04R2203/12 takes precedence
• CPC Class Codes: Y10S 367/905 Side lobe reduction or shading

Abstract

A class of planar arrays having broad frequency range applications for source location, source imaging or target illumination with projected beams is described in this disclosure. The non-redundant arrays are circularly symmetric and made up of a plurality of sensing and/or transmitting elements arranged so as to substantially eliminate grating lobes for a broad range of frequencies. Signals received from or transmitted to the elements are appropriately phased to control the beam of the array.

Claims

1. A broad frequency range circularly symmetric zero redundancy planar array for eliminating grating lobe contamination in source maps or projected beams comprising a plurality of sensing elements or transmitting elements spaced with various radii along a family of identical logarithmic spirals where members of the family are uniformly spaced in angle about an origin point and there are an odd number of members in the said family of identical logarithmic spirals.

2. The planar array defined in claim 1 in combination with means for receiving signal energy from each of said array elements over separate receiving paths.

3. The combination defined in claim 2 combined with means coupled to each of said receiving paths to process said signal energy to control the phase and amplitude of said array elements thereby controlling the main beam of said array.

4. The planar array defined in claim 1 in combination with means for feeding signal energy to each of said array elements over separate transmission paths.

5. The combination defined in claim 4 combined with means coupled to each of said transmission paths to process said signal energy to control the phase and amplitude of said array elements thereby controlling the main beam of said array.

6. The combinations as defined in claim 3 wherein said array elements are located along each said logarithmic spiral on concentric circles forming the geometric radial centers of equal-area annuli and on an innermost concentric circle whose radius is independently specified.

7. The combination as defined in claim 3 wherein said array elements are located along each said logarithmic spiral at equal radial increments between an inner and outer radial specification.

8. The combination as defined in claim 3 wherein said array elements are located along each said logarithmic spiral at logarithmically increasing radial increments between an outer and inner radial specification such that the radial increment between said elements along said logarithmic spiral increases as said spiral is traversed from the outermost to the innermost element.

9. The combination as defined in claim 3 wherein said array elements are located along each said logarithmic spiral at logarithmically increasing radial increments between an inner and outer radial specification such that the radial increment between said elements along said logarithmic spiral increases as said spiral is traversed from the innermost to the outermost element.

10. The combination as defined in claim 3 wherein said array elements are located along each said logarithmic spiral by means to achieve space density tapering.

11. The combination defined in claim 5 where said array elements are passive acoustic sensors (e.g., condenser microphones) and said means for receiving said signal energy and processing said signal energy to control the phase amplitude of said array elements is an N-channel signal conditioning system comprising a pre-amplifier, transmission line, and input module comprising signal conditioning and sample and hold analog-to-digital conversion capability for each channel, all input modules coupled to a common system bus connected to a data processing system for beamforming and resultant noise source map generation in the form of a contour plot.

12. The design of arrays as defined in claim 1 where specifications for logarithmic spiral angle, inner radius, outer radius, number of elements per spiral, number of spirals, and spiral element spacing method provide a circularly symmetric, zero-redundant, planar array.

13. The design of arrays defined in claim 12 where the number of elements in said arrays and outer radius of said arrays are arbitrary.

14. The combination as defined in claim 5 wherein said array elements are located along each said logarithmic spiral on concentric circles forming the geometric radial centers of equal-area annuli and on an innermost concentric circle whose radius is independently specified.

15. The combination as defined in claim 5 wherein wherein said array elements are located along each said logarithmic spiral at equal radial increments between an inner and outer radial specification.

16. The combination as defined in claim 5 wherein wherein said array elements are located along each said logarithmic spiral at logarithmically increasing radial increments between an outer and inner radial specification such that the radial increment between said elements along said logarithmic spiral increases as said spiral is traversed from the outermost to the innermost element.

17. The combination as defined in claim 5 wherein wherein said array elements are located along each said logarithmic spiral at logarithmically increasing radial increments between an inner and outer radial specification such that the radial increment between said elements along said logarithmic spiral increases as said spiral is traversed from the innermost to the outermost element.

18. The combination as defined in claim 5 wherein wherein said array elements are located along each said logarithmic spiral by means to achieve space density tapering.