Designe, Simulation and Performance Analysis of High Sensitivity and Wide Bandwitdh Hydrophone by Employing Suspended Gate in Low Frequnces

In the present article a novel structure is proposed to design and fabricate a high sensitivity wide bandwidth hydrophone. A MOSFET transistor with suspended gate has been used. Directed incident acoustic waves will cause deflection on suspended gate, which will turn into changes in gate-source capacitance and as a result leads to drain-source current variation. Here, acoustic waves will be detected by analysis of drain-source current obtained from changes in distance of gate and channel. In order to calculate sensitivity of proposed hydrophone, first by using finite element method displacement of gate as a response to acoustic wave is determined, then the current variation is determined in another simulation. Results indicate that sensitivity of -170db in low frequency which are in competition to other traditional works improved considerably. One noticeable point regarding this work is that higher sensitivity did not come at the cost of scarification of bandwidth, which was the case in many other works. Usable frequency of proposed hydrophone is from very low frequency up to 13.5 kHz and in contrast to piezoelectric based hydrophone there is no need for charge amplifier in vicinity of hydrophone. In addition, the dimensions of the proposed structure are smaller than conventional structures.