The rapid growth of remote, wireless and MEMS (Micro Electro-Mechanical System) devices recent have motivated the development of a self-powered system that can replace traditional electrochemical batteries. Piezoelectric energy harvesters are ideal for capturing energy from mechanical vibrations in the ambient environment. Numerous studies have been made of this application of piezoelectric energy conversion; however, the narrow frequency operation band has limited its application to generate useful power.  We have designed a wide-band energy harvester with an array/matrix of piezoelectric bimorphs connected by springs based on the 1D piezoelectric beam equations. The predicted result shows that the operation frequency band can be enlarged significantly by carefully adjusting the small end masses, length of the beam and spring stiffness. The results provide an important foundation for future broadband energy harvester design.