How to Choose the Radius of Curvature for Focused Piezo Ceramics
Audience: Engineers designing custom ultrasonic transducers
Goal: Help you pick a radius of curvature (ROC) that makes sense for your application, your medium, your manufacturing capability, and your test uncertainty.
Focused piezo ceramics are seductive. You pick a radius, the field "converges," the sensitivity jumps, and life is good. Until it isn't. In real transducers, ROC influences (1) focal distance, (2) beam width, and (3) how forgiving the design is to tolerance, mounting, and load variation. It also interacts with medium properties (speed of sound, attenuation, impedance), and with your ceramic's vibration mode, backing, and packaging.
This article is intentionally not a "plug numbers into one equation" guide. Those exist, they are useful, and they are also the fastest path to false confidence. Early-stage design needs a mental model that connects curvature to what you will actually measure on the bench.
Use this as a focused design guide: if you first need a broader comparison of discs, rings, tubes, rectangular plates, and focused curved parts, start with our geometry selection guide. This page is for the next step, when the real question is how radius of curvature should be chosen and reviewed.