SAW Sensor Module with Magnetic Alignment and Capacitive Coupling

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Solution Overview

Problem

Existing SAW sensor technologies are complex and require intricate adjustments and wiring for fluid analysis, limiting their practical application in chemical and biological fluid analysis.

Innovation Solution

A SAW sensor module with a disposable cartridge and a control and readout device that uses capacitive coupling and magnetic alignment, allowing for simple and stable signal transmission and alignment without complex adjustments, and includes a fluid frame for uniform travel distances and a RFID chip for identification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional SAW sensor technologies are used for fluid analysis, then measurement capability is achieved, but device complexity and adjustment requirements increase

Engineering Contradiction:
Improvefluid analysis capabilityVSAvoidadjustment and wiring complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system is divided into a reusable control and readout device and a disposable cartridge containing the SAW sensor. This segmentation allows the complex sensor to be pre-assembled and tested in the cartridge, while the user only needs to replace cartridges rather than perform complex adjustments or wiring.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cartridge containing the SAW sensor is designed as a disposable component. This eliminates the need for complex recalibration and adjustment after each use, as users simply replace the entire cartridge with a new pre-calibrated one, significantly reducing operational complexity.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If precise alignment of coupling electrodes is required for signal transmission, then measurement reliability improves, but alignment precision requirements increase

Engineering Contradiction:
Improvesignal transmission reliabilityVSAvoidelectrode alignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The mechanical alignment system is replaced with magnetic alignment. Magnetic elements in the cartridge interact with corresponding magnetic elements in the control device to automatically align the coupling electrodes, eliminating the need for precision mechanical positioning and reducing manufacturing tolerance requirements.

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

Solution Approach 2:

The magnetic alignment system enables self-alignment of the cartridge with the control device. When the cartridge is placed on the control device, the magnetic attraction automatically positions the coupling electrodes in the correct relative positions without requiring manual adjustment or high-precision manufacturing.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If capacitive coupling is used for signal transmission, then connection simplicity improves, but signal loss may increase

Engineering Contradiction:
Improveconnection simplicityVSAvoidsignal loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

A coupling liquid is introduced as an intermediary medium between the coupling electrodes to enhance capacitive coupling. The coupling liquid with appropriate dielectric properties improves the electrical connection between electrodes, reducing signal loss while maintaining the simplicity of capacitive coupling without direct physical contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Facilitates easy, reliable, and cost-effective fluid analysis with reduced measurement errors and environmental protection, enabling simultaneous measurement and identification of fluid samples.

Implementation Method 1

The alignment of the device coupling electrodes to the cartridge coupling electrodes is achieved simply by the magnetic attraction between the at least one alignment element and the at least one magnetic element, which automatically aligns the cartridge on the control and readout device.

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Implementation Method 2

signal transmission from the control and readout device to the cartridge and back to the control and readout device is achieved simply and with low loss via capacitive coupling between the control and readout device and the cartridge.

Methodology Applied
Scientific EffectCapacitive coupling: Capacitance

Implementation Method 3

Since an externally applied electric field causes mechanical deformation of the piezoelectric substrate, the substrate is alternately stretched and contracted.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 4

At the transmitter, the alternating voltage signal is converted into a surface acoustic wave and emitted into the substrate. The surface acoustic wave causes charge displacements in the piezoelectric substrate, which in turn generate an alternating voltage signal in the finger-like structures of the receiver.

Methodology Applied
Scientific EffectSurface acoustic wave: Surface Acoustic Wave

Data Source

PatentEP4431933B1Saw sensor module
Publication Date: 2026.01.21 BIO SAW GMBH
  • EP4431933B1 patent drawingFigure 1~2
  • EP4431933B1 patent drawingFigure 3
  • EP4431933B1 patent drawingFigure 4~5

AI summary

The present invention relates to a SAW sensor module comprising a cartridge with a sensor chip made of piezoelectric material and at least one SAW sensor formed thereon, and at least one control and readout device for the at least one SAW sensor.According to the invention, the control and readout device has a circuit board on the front of which device coupling electrodes are formed, which are connected to a device connection formed on the circuit board by means of electrical conductors passing through the circuit board, and the cartridge has cartridge coupling electrodes which are capacitively coupled on the one hand to the device coupling electrodes and on the other hand to sensor electrodes of the at least one SAW sensor, wherein at least one magnetic element is formed on the circuit board and the cartridge has at least one metallic and/or magnetic alignment element which aligns itself with the at least one magnetic element.