I. INTRODUCTION 1 1.1 Research Background 1 1.2 Research Objective 11 II. DESIGN AND FABRICATION 14 2.1 Spherical hydrophone 14 2.2 Directional hydrophone 17 2.3 Assembly of the prototype vector hydrophone 30 III. CHARACTERIZATION AND RESULTS 32 3.1 Characterization of the Fabricated Vector Hydrophone 32 3.1.1 In-air characterization of the directional hydrophone 32 3.1.2 Underwater characterization of the vector hydrophone 35 3.2 Optimization of the vector hydrophone 39 3.2.1 Second optimization of vector hydrophone 39 3.2.2 Third optimization of vector hydrophone 49 IV. CONCLUSION AND DISCUSSION 57 4.1 Conclusion 57 4.2 Discussion and Future work 57 REFERENCES 59 요 약 문 62