Radiation Pattern Shaping of a Two-Element, Concentric Ring Transducer Using Phase and Amplitude Shading.
Abstract
A high-frequency transducer which gives usefully uniform radiation into a half space is required for use as a target locator in an underwater acoustic range. Phase and amplitude shading of a two-element transducer consisting of a central circular piston and a concentric annular ring has been proposed to meet the requirement. A transducer resonant at 74 kHz but scaled in terms of wave length to 25 kHz in the transverse dimension has been constructed and tested at both frequencies. Exceptionally wide radiation patterns with major lobe widths of the order of 150 degrees (10dB down) were obtained. At the scaled frequency computer model predictions based on simple theory agreed well with the measured radiation patterns. At the resonant frequency, however, predicted secondary lobe details were not found in the patterns. These discrepancies have been attributed to the non-uniform motion of the radiating surfaces due to mutual coupling effects through the transducer structure and the transmission medium. In spite of these minor problems associated with the prototype transducer, promising results have been obtained and have shown the design concept to be a valid and viable one. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1975
- Accession Number
- ADA020060
Entities
People
- Albert Hampden Proctor Shaw
Organizations
- Naval Postgraduate School