Single Acoustic Transducer with Adaptative Radiation Pattern for Underwater Networks

Abstract

Underwater acoustic networks are constrained by low bandwidth, long propagation delays, multipath, and spatially distributed interference, namely due to neighboring nodes. Directional transmission can improve the signal-to-interference-plus-noise ratio and increase spatial reuse, but conventional phased arrays are often too large and complex for compact underwater sensor nodes. This paper presents a design and feasibility study of a single spiral acoustic projector that combines calibrated circular and spiral radiation modes to synthesize an electronically steerable directional pattern. The study focuses on the transducer excitation concept, radiation-field control, and its potential integration within a networking architecture. Finite-element simulations show that the maximum response direction can be electronically rotated while preserving coherent phase along the selected bearing. Finally, a conceptual protocol framework is outlined in which circular/spiral signaling supports azimuth estimation and directional transmission carries data, indicating a path toward medium access control schemes that exploit spatial reuse in small-scale underwater acoustic networks.