A New Approach to Superdirective Arrays
Abstract
The concept of defined nulls in the directional response of arrays and the introduction of electrical delays to achieve the desired placement of the nulls provide a new approach to acoustical superdirective arrays. The shading that results is a variant of binomial shading in that the number of times a given element contributes to the array output is determined by the appropriate binomial coefficient, but the signal from the element undergoes a possibly different electrical delay each time the element contributes. For an end-fire condition, the maximum array gain (assuming isotropic noise) is equal to the square of the number of elements in the array. The methods used yield results for three- and five-element broadside arrays that are equivalent to those obtained earlier by R. L. Pritchard. The type of array described responds to a higher order gradient of the pressure field rather than to the pressure field itself. A digital method for implementation of such an array is presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 05, 1971
- Accession Number
- AD0718322
Entities
People
- A. Z. Robinson
Organizations
- United States Naval Research Laboratory