CMUT Ultrasonic Link for High-Rate Through-Body Data Transfer

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Solution Overview

Problem

Current wireless communication methods, such as r.f. and electromagnetic transmission, are limited by tissue attenuation and interference in medical environments, making it difficult to achieve high-data-rate communication through the human body for devices like pacemakers and catheters.

Innovation Solution

A miniaturized wide band through-body ultrasonic communication system using MEMS or capacitive microelectronic ultrasonic transducers (CMUTs) that operate in a collapsed mode with broad bandwidth, allowing for efficient data transfer through liquid-like media like human tissue, and integrating microelectronic circuitry for encoding and decoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If r.f. or electromagnetic communication is used for wireless communication through the body, then wireless communication capability is achieved, but the communication is highly attenuated by tissue and encounters interference from other medical equipment

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidtissue attenuation and electromagnetic interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces electromagnetic field-based communication with acoustic field-based communication. Ultrasonic waves mechanically vibrate through tissue rather than using electromagnetic fields, thereby avoiding electromagnetic interference from medical equipment and reducing tissue attenuation effects. The ultrasonic transducer converts electrical signals to acoustic waves that propagate through the body tissue to the external receiver.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental parameter of the communication medium from electromagnetic waves to acoustic waves. By operating in the ultrasonic frequency range (20 kHz to several MHz), the system exploits the different propagation characteristics of acoustic waves through tissue, which are less affected by electromagnetic interference and exhibit different attenuation properties compared to r.f. electromagnetic waves.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If r.f. or electromagnetic communication is used, then wireless communication is achieved, but the communication is band-limited when operating through tissue

Engineering Contradiction:
Improvedata transfer rateVSAvoidbandwidth limitation
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent employs dynamic frequency modulation of ultrasonic waves to encode data. By varying the frequency, amplitude, or timing of ultrasonic pulses, the system can dynamically encode multiple bits of information, increasing the effective data transfer rate. The broad bandwidth of ultrasonic frequencies allows for higher symbol rates and more efficient modulation schemes compared to band-limited r.f. communication through tissue.

Inventive Principle:
Principle #15Dynamics

3Reliability

If wiring is used for communication in catheters or implanted devices, then reliable communication is achieved, but the small size of the device affords only limited space for communication lines

Engineering Contradiction:
Improvecommunication reliabilityVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent eliminates the need for physical communication wires by substituting wired communication with wireless acoustic communication. The ultrasonic transducer inside the small catheter or implant generates acoustic waves that transmit data through tissue to an external receiver, completely removing the requirement for communication conductors and freeing up device space for other functional components.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If ultrasonic transducer operates in kHz frequency range, then wireless through-body communication is achieved, but the data transfer rate is limited

Engineering Contradiction:
Improvedata transfer rateVSAvoidcommunication speed
Core Design Contradiction:
ProductivityVSSpeed

Solution Approach 1:

The patent changes the operating frequency parameter from low kHz range to higher ultrasonic frequencies (MHz range). This frequency increase allows for shorter wavelengths and higher modulation rates, directly increasing the achievable data transfer rate. The system exploits the full ultrasonic spectrum to optimize the balance between penetration depth and data transmission speed.

Inventive Principle:
Principle #35Parameter changes

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 system achieves high data transfer rates of up to Mb/sec with low energy consumption and immunity to noise and interference, enabling reliable communication within the body without the need for conductive wires.

Implementation Method 1

an ultrasonic transducer adapted to transmit acoustic waves at a communication frequency is located in the cavity

Methodology Applied
Scientific EffectUltrasonic wave transmission: Ultrasound

Implementation Method 2

A preferred ultrasonic transducer for such communication is a MEMS or capacitive microelectronic ultrasonic transducer (CMUT) which can be controlled during manufacture and implementation to exhibit a broad bandwidth

Methodology Applied
Scientific EffectCapacitive microelectronic transducer operation: Capacitance

Data Source

PatentEP3191233B1Wide band through-body ultrasonic communication system
Publication Date: 2022.11.23 KONINKLIJKE PHILIPS NV
  • EP3191233B1 patent drawingFigure 1a~1c
  • EP3191233B1 patent drawingFigure 2~3
  • EP3191233B1 patent drawingFigure 4~5

AI summary

A wide band through-body communication system communicates data through the body ultrasonically. A MEMS device such as a CMUT transducer is configured to transmit and/or receive ultrasonic data signals within a broad band of operating frequencies. The transducer transmits the ultrasonic data signals through the body to a similarly configured ultrasonic receiver, and/or receives ultrasonic data signals which have been conveyed through the body from a similarly configured ultrasonic transmitter for decoding and processing. In a preferred implementation a CMUT transducer is operated in a collapsed mode.