Characteristic analysis method for capacitive micromachined ultrasonic transducer

Abstract

The invention provides a characteristic analysis method for a capacitive micromachined ultrasonic transducer (CMUT), which aims at performing effective analysis on displacement, acceleration, sound pressure characteristics and receiving characteristics under the circumstances of different emission signals. The characteristic analysis method for the CMUT comprises the step: firstly establishing an infinitesimal state equation SIMULINK model of the CMUT in an emission state and an infinitesimal state equation SIMULINK model of the CMUT in a receiving state, wherein the infinitesimal state equation SIMULINK model of the CMUT in the emission state comprises a CMUT vibration system module and an electrostatic force module, and the infinitesimal state equation SIMULINK model of the CMUT in the receiving state comprises a CMUT vibration system module, an electrostatic force module and a current output module; the electrostatic force module calculates an electrostatic force Fe by determining parameters, such as driving voltage V, an initial gap g0 between an upper electrode and a lower electrode, and displacement; by determining parameters, such as the electrostatic force Fe, equivalent mass, equivalent spring constant K and equivalent impedance R, the CMUT vibration system module establishes a lumped parameter system, calculates vibration displacement and vibration velocity, and outputs the displacement as feedback quantity to the electrostatic force module, thereby multiplying vibration velocity and radiation resistance to calculate sound radiation pressure.

Description

technical field [0001] The invention relates to a characteristic analysis method of a capacitive micromachined ultrasonic sensor. Background technique [0002] Ultrasonic imaging technology has been widely used in many fields such as medical ultrasonic diagnosis, medical ultrasonic therapy, nondestructive testing, ultrasonic microscope and marine topography detection, and ultrasonic sensor is one of the key components to realize ultrasonic imaging. Capacitive micromachined ultrasonic transducer (CMUT) is a new type of ultrasonic transducer based on the electrostatic energy conversion mechanism. Compared with piezoelectric ultrasonic transducers, it has many advantages: (1) It has lower acoustic impedance and does not require The complex impedance matching layer is easy to match the impedance of air, water, human tissue and other media. (2) It has a wider bandwidth. (3) The array design is flexible, and has good consistency, repeatability and high precision. (4) It is easy...

AI Technical Summary

Problems solved by technology

At present, there are many methods for analyzing the characteristics of CMUT microelements. The commonly used analysis models include equivalent circuit model, finite element analysis model, and finite difference model. However, these methods have some shortcomings: (1) For the equivalent circuit model, At present, only the analysis methods for small signals are relatively mature; (2) The finite element analysis model usually uses professional finite element analysis software such as ANSYS. For CMUTs containing many microelements, the calculation process is very time-consuming when using the finite element analysis model; (3) The finite difference model reduces the analysis time by using the thin disk theory and the boundary element method. However, the current finite difference model cannot analyze the nonlinear characteristics of CMUT microelements, nor can it analyze large signals. It can only linearize small signals. model for analysis

Images