Multi-Track SAW Sensor Coding With Delayed Orthogonal Sequences

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Solution Overview

Problem

In multi-sensor environments, existing surface acoustic wave (SAW) sensors face challenges in identifying and transmitting sensor information simultaneously, requiring enhanced coding techniques to differentiate between sensors while maintaining device size and cost efficiency.

Innovation Solution

The implementation of orthogonal frequency coding using multiple parallel acoustic tracks with phase shifting and delaying techniques, where each track produces a unique code sequence, and the sum of these sequences forms a comprehensive orthogonal coded signal, increasing coding capacity without significantly increasing device size or cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If multiple parallel acoustic tracks are used to increase coding capacity, then the coding capacity is doubled, but the device width increases slightly

Engineering Contradiction:

Improvecoding capacityVSAvoiddevice width

Core Design Contradiction:

Loss of informationVSArea of stationary object

Solution Approach 1:

The device is segmented into multiple parallel acoustic tracks, each carrying independent code sequences. This segmentation allows the coding capacity to be increased by adding more tracks without requiring a proportional increase in the length of each individual track, thereby managing the trade-off between coding capacity and device area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-dimensional serial code sequence to a multi-dimensional parallel structure by introducing multiple acoustic tracks. This dimensional change allows coding capacity to scale with the number of tracks while keeping individual track lengths manageable, thus controlling the overall device area growth.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of information

If the device length is increased to accommodate more code sequences, then the coding capacity increases, but the device becomes significantly larger

Engineering Contradiction:

Improvecode informationVSAvoiddevice length

Core Design Contradiction:

Loss of informationVSLength of moving object

Solution Approach 1:

Instead of extending a single code sequence linearly, the code information is segmented across multiple parallel tracks. Each track contains a compressed code sequence, and the collective information from all tracks provides the total coding capacity, thereby reducing the required length of each individual track and the overall device length.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple parallel acoustic tracks are merged to collectively provide the complete code information. The sum of code sequences from all tracks yields the comprehensive coded signal, allowing the device to achieve high coding capacity without requiring any single track to be excessively long.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If orthogonal frequency coding is implemented to differentiate sensors, then sensor identification capability is improved, but the device complexity increases

Engineering Contradiction:

Improvesensor identificationVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention uses orthogonal frequency coding by varying the frequency parameters of the acoustic signals across multiple tracks. This parameter change approach enables sensor identification and differentiation without requiring fundamentally new device structures, thereby managing the complexity while improving adaptability.

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

This approach doubles the coding capacity of SAW sensors while maintaining a similar device length, providing a secure and efficient method for sensor identification and information transmission in harsh environments, with a slightly wider device width.

Implementation Method 1

a transducer (310) and plural acoustic tracks (320, 325, 330, 335, 340, 345) each having a bank of reflectors fabricated on the substrate

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

orthogonal frequency coded surface acoustic wave sensors and, in particular, to apparatus, systems, devices and methods for generating, distributing, processing and detecting orthogonal frequency coding for surface acoustic wave and silicon tags and sensors

Methodology Applied

Scientific EffectSurface acoustic wave propagation: Surface Acoustic Wave

Implementation Method 3

Each bank of reflectors includes plural reflectors coupled together each producing an orthogonal frequency within a bandwidth to generate the code sequence for a corresponding one of the plural tracks

Methodology Applied

Scientific EffectAcoustic reflection: Reflection

Data Source

PatentUS7825805B2Delayed offset multi-track OFC sensors and tags

Publication Date: 2010.11.02 UNIV OF CENT FLORIDA RES FOUNATION

AI summary

Apparatus, systems, devices and methods for providing an orthogonal frequency coding technique for surface acoustic wave sensors incorporating the use of multiple parallel acoustic tracks to provide increased coding by phase shifting and delaying a code sequence. The surface acoustic wave sensor includes parallel tracks with multiple reflectors with differing delay offsets to form a complex code sequence. The reflectors may be uniform, but alternatively could include fingers withdrawn, have reflector position modulation, differing frequencies or be spatially weighted.