Gain bandwidth products for capacitive pressure transducers

Abstract

The compromise between the sensitivity and bandwidth of a pressure transducer using constant charge mode capacitive electro-mechanical transduction is examined. The performances of circular pressure summing diaphragms built around piston, plate and membrane structural elements are compared by defining a gain bandwidth product, analogous to the parameter used in active electronics. It is demonstrated that pressure transducers built around membrane diaphragms offer the highest gain bandwidth product. Recent developments in the ‘micromachining’ of silicon into structural components have motivated the study of new pressure transducers having plate diaphragms. The gain bandwidth product of these devices is shown to be less than one-sixth of that of a comparable membrane diaphragmed transducer.