Piezoelectric PZT-air composites with a complex design optimized for hydrophones were fabricated as arrays of hundreds of 60 mu units using a microfabrication technique involving coextrusion of mixtures of thermoplastic with PZT powder or carbon powder. The measured piezoelectric coefficient was 300 pC/N with a figure of merit of 18 pm(2)/N, in excellent agreement with the predicted properties.