Contoured CMUT Electrodes for Higher Output and Lower Harmonics

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Solution Overview

Problem

Existing capacitive micromachined ultrasonic transducers (CMUTs) face limitations in transmit output pressure and receive sensitivity, with flat electrodes restricting the electromechanical transformer ratio and requiring inefficient excitation methods that generate harmonics and necessitate mode switching.

Innovation Solution

The use of contoured electrodes with non-planar designs and half-wave pulse excitation techniques, including unipolar pulse trains, to enhance the deflection of the plate and improve ultrasound transmission and reception efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a flat electrode is used in CMUT, then the manufacturing process is simple, but the transmit output pressure and receive sensitivity are limited

Engineering Contradiction:

Improveelectrode fabrication simplicityVSAvoidtransmit output pressure

Core Design Contradiction:

Ease of manufactureVSPower

Solution Approach 1:

The patent applies curvature to the electrode structure by forming a contoured electrode with a non-planar surface that matches the deflected shape of the outer plate. This curved electrode configuration increases the electromechanical transformer ratio, thereby improving transmit output pressure and receive sensitivity while maintaining manufacturing feasibility through established fabrication processes

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Ease of operation

If conventional excitation methods are used, then the device operation is simple, but harmonics are generated and mode switching is required

Engineering Contradiction:

Improveexcitation method simplicityVSAvoidharmonic generation

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent employs half-wave pulse excitation with periodic zero-amplitude intervals between pulses. This periodic excitation pattern eliminates harmonics by exciting only the fundamental mode and removes the need for mode switching, while the simple pulse train structure maintains ease of operation through standard signal generation capabilities

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The contoured electrodes and pulse excitation methods increase transmit output pressure and receive sensitivity by up to 100% and 150%, respectively, while reducing harmonics and eliminating the need for mode switching, with potential for lower driving voltages and improved energy efficiency.

Implementation Method 1

Voltage applied between the contoured electrode and the plate deflects the plate

Methodology Applied

Scientific EffectElectrostatic attraction: Electrostatics

Implementation Method 2

Capacitive micromachined ultrasonic transducer

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS20260027584A1Methods of operating and manufacturing capacitive micromachined ultrasonic transducer with contoured electrode

Publication Date: 2026.01.29 THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIV

AI summary

Aspects of this disclosure relate to driving a capacitive micromachined ultrasonic transducer (CMUT) with a pulse train of unipolar pulses. The CMUT may be electrically excited with a pulse train of unipolar pulses such that the CMUT operates in a continuous wave mode. In some embodiments, the CMUT may have a contoured electrode.