Plane arrays – Fundamental investigations for correct steering by means of sound field calculations

• Published in: Wave motion 2007-03, Vol.44 (4), p.248-261
• Main Author: Kühnicke, Elfgard
• Format: Article
• Language: English
• Subjects: 43.20.Bi; 43.20.Gp; 43.35.+d; 43.35.Yb; 43.38.+n; 43.38.Hz; 43.60.Fg; 46.40.Cd; Acoustics; Beam steering; Delay times; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Grating lobes; Integral transform method; Mathematical methods in physics; Maximal steering angle; Numerical approximation and analysis; Optimization of ultrasonic arrays; Ordinary and partial differential equations, boundary value problems; Physics; Sound field calculations; Time harmonic and transient field; Transduction; acoustical devices for the generation and reproduction of sound; Water/steel-configuration
• ISSN: 0165-2125; 1878-433X
• DOI: 10.1016/j.wavemoti.2006.10.003

The most crucial problem with plane arrays is correct steering without grating lobes. The paper deals with optimization of the geometrical parameters and of the steering of phased arrays for water and for testing with the immersion technique. It gives a brief introduction into theory, investigates the existence and magnitude of grating lobes and deals with the limitation of steering angle. It suggest a fitting of steering angles with a fast approach to calculate sound fields. The paper shows also that grating lobes can appear in the transient field for extreme cases even if there are no lobes in the time harmonic field at the center frequency. This contradicts the common expectation. The paper deals also with a water/steel-configuration for testing with immersion technique. It is discussed that grating lobes and the limitation of steering in water strongly effect the sound field transmitted into steel.