초음파 센서의 혼 가이드 형상에 따른 음향 지향성

Abstract

This study addressed horn guides attached to an ultrasonic sensor to improve acoustic directivity. Because an ultrasonic sensor with better directivity can measure longer distances, it is necessary to study methods of improving directivity by attaching a horn guide. We analyzed the acoustic characteristics of an ultrasonic sensor with a horn guide of various shapes by the finite element method in order to observe the acoustic directivity depending on the horn guide shape. We considered conical, exponential, and parabolic horns as well as the hornless case and examined the directional sound pressure distribution at a certain distance from the exciting point of the sensor and sound pressure magnitude along the axial direction. Experiments were performed to verify the analysis results. We used ultrasonic sensors attached with a horn guide to transmit ultrasonic waves and to measure the sound pressure of ultrasonic waves reflected from a plane. The results of finite element analysis and experiments consistently demonstrate the directivity appeared in the order of conical, exponential, and parabolic horns, followed by the hornless case. We observed that the conical horn has the best directivity.