Introduction to Sonar Transducer Design

4Sonar Projectors

In this chapter, we pull from the material developed in previous chapters to develop performance models and design concepts for sonar projectors. In Chapter 1, we discussed how waves propagate in fluid media and how apertures can be designed to “shape” the acoustic energy into a beam. In Chapter 2, we introduced the concept of a mechanical/acoustical equivalent circuit. In that chapter, we learned how propagating waves act like damped spring and mass systems. Chapter 3 presented an introduction to waves in solid media and piezoelectricity. In this chapter, we will explore different basic transducer designs and see how the elements of the previous chapters can be combined to produce an effective underwater sonar design.

4.1 Tools for Underwater Sonar Projector Design

4.1.1 Assembling Circuit Elements

We construct equivalent circuits for transducers by combining the equivalent circuits of transducer elements. In the previous chapter, we determined that non‐piezoelectric elements could be described in terms of two‐port networks. And, we found that piezoelectric elements can be described in terms of three‐port networks. In this chapter, we learn how to combine these networks, and other elements, to develop a complete equivalent circuit for a transducer. In this section, we will develop the rules for combining the equivalent circuit models of transducer elements.

As an example, let’s consider the tonpilz transducer shown in Figure 4.1-1. This tonpilz transducer ...