Abstract
Most directional acoustic transducers and arrays have beam widths that vary with frequency. To overcome these limitations, constant beam width transducers (CBTs) were conceived to maintain a stable radiation pattern across frequencies and thus provide consistent directivity. This work presents a continuous toroidal cap source that achieves a constant beam width pattern in both the horizontal and vertical planes, providing controlled and frequency-independent sound radiation in multiple directions. The performance of the radiation pattern is evaluated according to a parametric study involving geometrical properties of the toroidal cap and shading techniques. Results show improved performance for a two-dimensional (2D) cosine shading with respect to uniform shading. This study offers new insights that can be directly applied to the design of 2D CBTs and presents a model for stable, multidirectional sound radiation suitable for practical transducer matrices.
