Sensitivity Improvement Of Hydrophone Employing Suspended And Proof Mass Gate Of Transistor In Low Frequencies

In this paper, a new hydrophone sensor in low frequency is designed and simulated. The transducer mechanism is based on variation of gate source capacitor in MOSFET transistor, while the transistor gate is suspended using two beams. In response to incoming acoustic wave, gate goes under deformation and causes variation of gate-source capacitor. As a result, acoustic wave alters the drain source current of the MOSFET transistor. In contrast to previous studies, instead of using uniform rectangular gate, the comb-drive gate is used so as to increase the gate-source capacitor. First, structures and parameters such as pressure, stress and thickness of the gate are carried out. Finally, for different materials the sensitivity is calculated and compared with previous studies. By employing the finite-element-method simulation software, sensitivity and bandwidth are calculated. Simulation results indicate high sensitivity around  in low frequencies. The proposed hydrophone shows flat frequency response in rang of 10-11400 Hz.