A new, two-dimensional model is presented for predicting the behaviour of tall, thin piezoelectric transducer structures, typical of those encountered in many ultrasonic phased array assemblies. Based on linear systems theory, the model may be represented in block diagram format, utilising feedback and feedforward loops to model mechanical and piezoelectric cross coupling, in addition to secondary and tertiary piezoelectric generation. As a result, the model permits a ready understanding of the electrical, mechanical and piezoelectric interactions which take place when two principal vibrational modes are present within a transducer structure. Comprehensive experimental and theoretical results are shown to produce close agreement, and compare favourably with alternative modelling strategies. It is considered that this novel approach will be of considerable benefit to the analysis and understanding of the transduction process within such structures.