January 2010 Page 1

Delivering the Promise of Surface Acoustic Wave Sensors

January 2010 Page 2

What’s a wireless and passive sensor?

• « Standard » wireless sensor

Sensitive Element

Signal Processing

Wireless sensor

Wireless communication link

SAW sensitive element

Signal processing (could be placed in a

safe environment)

Wireless AND passive SAW sensor

Wireless communication link (up to 3m)

• SAW wireless AND passive sensor

January 2010 Page 3

Value added by SENSeOR’s solutions

• Wireless – up to several meters

• Passive – no battery required, no electronic at the sensor level

• Robust, reliable, stable – well adapted for harsh environments

• Miniature – small, light, multifunction devices

• High performances and reliability – unique sensitivities and ranges

• Cost effective and green technology (no recycling of battery)

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How it works!

January 2010 Page 5

SAW Technology - Introduction

• Based on their piezoelectric properties, certain materials such as Quartz (SiO2), Lithium Niobate (LiNbO3) and Lithium Tantalite (LiTaO3) create a mechanical displacement (surface acoustic waves - SAW) if an electric field is applied.

• The propagation of the SAW depends on the geometry of the substrate and the material parameters. These material constants are subject to environmental conditions: – mass loading (electrode, silica, additional layer ..)– stress (external forces, differential thermal stress)– Temperature

• Sensing with acoustic waves is based on measuring variations of acoustic propagation velocity of wave, or wave attenuation.

• 2 types of structures : resonators and delay lines

January 2010 Page 6

Principle of SAW sensors (resonators)

Piezoelectric substrate

Mechanical displacement

(e.g. 434MHz)

Interrogation signal to the sensor (f0) Generation of an acoustic wave on the piezoelectric substrate Response of the sensor sent back to the interrogator (f0+DF according to temperature for example)

January 2010 Page 7

Principle of SAW interrogation

Interrogator

charge

Interrogator

discharge

P, T, ID, etc.Sensor Sensor

1. RF Pulse sent to the

resonators

2. Load of the resonators

3. Answer from the resonators

4. Answer analysis

January 2010 Page 8

SAW Resonators

• A resonator is composed of IDTs in the center of the structure and reflecting gratings or electrodes on both sides of the IDTs.

• The IDT is a bi-directional structure, it means the energy propagates on both sides at the same intensity. The reflecting gratings or electrodes reflect the energy produces by the IDT.

• A resonant cavity is obtained and characterised by its resonant frequency.

• Advantages: high quality factor, low insertion losses

• Disadvantages: frequency sensitivity to manufacturing tolerances

Resonator Principle

Example of realization (8x4mm)

January 2010 Page 9

Example of a SAW pressure sensor

This SAW sensor is composed of 3 SAW resonators located on the same substrate (Qz):

• Resonator n°3 (resonant frequency f3) is located on the diaphragm done by quartz micromachining and will be sensitive to pressure and temperature

• Resonators n°1 (resonant frequency f1) and n°2 (resonant frequency f2) will not be sensitive to pressure but only to temperature

• Therefore : (f3-f2) information about pressure variations(f1-f2) information about temperature variations

•Other types of structures can be used according to the pressure measurement range, in particular for high pressure

January 2010 Page 10

Frequency response of a SAW pressure sensor

Variations fréquence F(P,T) ; P varie de 0 à 5 bars

433

433,2

433,4

433,6

433,8

434

434,2

434,4

434,6

434,8

-60 -40 -20 0 20 40 60 80 100 120 140

Température T (°C)

F1

,F2

,F3

en

MH

z

Example of frequency response of a SAW pressure sensor at 434MHz(frequency variations from 0 to 5bars)

F1 (red)F2 (green)F3 (blue)

January 2010 Page 11

• A delay line is composed of IDTs at one side of the device and reflecting gratings or electrodes at the other side. The IDT generates an impulse wave which propagates to the electrodes. The impulse wave is reflected by the electrodes or reflecting gratings to the IDT.

• We therefore measure the propagating time of an impulse.

• Advantages: no sensitivity of phase shifts to manufacturing tolerances

• Disadvantages: larger size than resonators for the same Q factor, higher insertion losses

Principe de la ligne à retard

Exemple de réalisation (9x3,8mm)

SAW Delay Lines

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The products and applications

January 2010 Page 13

Unique sensing solutions

Temperature

Stress, Pressure

Others to come (e.g. chemical)

Rotating and moving partsInside engines, turbines, pumps,

tyres, gearboxes…

Harsh environmentsHigh temperatures (ovens…),

strong electromagnetic fields (HV breaker boxes…), explosive

atmospheres…

Confined placesInside materials (concrete, plastic,

…), underground pipes, tanks, industrial valves…

ApplicationsTechnology & Core Benefits

Batteryless

Works where no others work

High performance, cost effective

Compact , Robust

Wireless

Our offer to your applications

Green technology

January 2010 Page 14

Main products available

• Wireless SAW Temperature sensors– typical measurement range from -40°C up to +200°C – ongoing projects for high temperatue

up to +400°C– SED100 in thermowell packaging– One product in production (4000pcs/year) for marine application in diesel engines

• SAW starter kit – SAW TDK1 with SAW temperature sensors – used for feasibility study in customers

environment

• SAW pressure and SAW stress sensors– Prototype available for pressure measurement range up to 20bars– SAW stress resonator available for tests

• Wireless SAW readers– Working at 434MHz– EC certified

January 2010 Page 15

Optimisation of each element of the system

• Based on customers specifications, Senseor has competencies to optimise the whole system

– The wireless SAW reader (EC certified)

– The SAW sensor

– The antennas

Examples of SAW sensorsLeft : SAW temperature sensor 5x5mm

Middle : SAW stress resonator 7x5.2mmRight : SAW temperature sensor (delay line) 9x3.8mm

Meander antenna at 434MHz3 cm

11 cm

January 2010 Page 16

Temperature measurement in marine diesel engines

• SAW temperature sensor (delay line) placed on the rotating part

• Interrogation through a fixed antenna

• Direct and continuous measurement of temperature

• Compact and simple installation

Source : Kongsberg Maritime

January 2010 Page 17

Configuration with fixed interrogator linked to a PC

Fixed reader connected through RS232 to a PC

(IHM software supplied to monitor real-time measurements)

SAW sensor

Possible interfaces:Wireless (Zigbee, Bluetooth…)Analog (0-5Volt)RS232 / USBCANBus…

January 2010 Page 18

Multi-sensors configuration – example inside a confined space

• Senseor has developed a SAW reader able to interrogate up to 12 sensors with one single antenna (each sensor having its own resonant frequencies)

Metallic cage Wideband SAW reader

SAW sensors (e.g. in harsh environment)

January 2010 Page 19

Multi-sensors configuration with multiplexing of antennas

• Senseor has developed a SAW reader with up to 4 antenna outputs in order to allow the interrogation of multiple sensors in different places with one single reader

January 2010 Page 20

SAW sensors on rotating parts

• Being wireless and very light (2g only), the SAW sensor can be easily placed on rotating parts (such as rotors, tires…)

SAW reader (can be placed outside of electric / magnetic fields)

SAW sensors with antennae on the rotor

RF cable

Fixed antenna of the SAW reader

Possible interfaces: Wireless (Zigbee, Bluetooth…) Analog (0-5Volt) RS232 / USB CANBus…

January 2010 Page 21

SAW Temperature Evaluation kit – SAW TDK1

SAW reader V3.3 with monopole antenna and USB connection

SAW sensor with PIFA antenna for temperature monitoring of surface

SAW sensor probe (6mm diameter)

with antenna – SED120

SAW sensor in thermowell packaging

with antenna (SED100)

January 2010 Page 22

Formerly unachievable sensing solutions…on moving parts

• Wireless bearing temperature monitoring– System certified for diesel engines in marine environment (based on

delay lines) : temperature up to 170°C, sensor passage speed up to 80m/sec, typ. accuracy +/-1°C

• Motors and tires temperature monitoring– Temperature up to 200°C – Up to 5000rpm

• Key benefits– significantly reduced risk of unforeseeable repair costs, improved

operational safety, reduced false alarm rate, compact and simple installation, improved machines performances

January 2010 Page 23

Formerly unachievable sensing solutions…in confined spaces

• HV equipments– Multiple sensors interrogation (e.g. 10), optimization of the sensor by selecting the

frequency (between 433MHz and 2.45GHz) and the piezoelectric substrate

• Level measurements inside tanks– Sensor immerged inside hydrocarbons, interrogation through polyethylene walls of

tanks, detection of level variations of few cm

• In-concrete building and soil– range of 30 cm demonstrated in wet soil (first trials), complement to current Ground

Penetrating Radar (GPR) methods (“cooperative target”)

• Implantable blood pressure– Miniature implantable pressure and temperature sensor at 2.45GHz

• Key benefits– No battery and wireless: compatible with long-term monitoring of building,

biocompatible, high reliability of sensors inside tanks (no problems with cables and electronics)

January 2010 Page 24

Formerly unachievable sensing solutions…in harsh environments

• In high electrical and magnetic fields– SAW sensors are able to withstand to 2T magnetic field, 10kV voltage

and 2kA current (tests already performed under these conditions)

• In high temperature– Some piezoelectric materials are well suited to temperature

measurements up to 400°C (even 600°C): research programs are in progress to address this subject

• Key benefits– Robust and reliable solutions for the monitoring of critical parts in a

process or in a machine

January 2010 Page 25

The Company

January 2010 Page 26

Overview of the company

• SENSeOR has been created in February 2006 by Gerhard HEIDER to combine world-leading competencies and capabilities in acoustic wave (e.g. SAW) based sensing.

• SENSeOR’s headquarter is located in Sophia-Antipolis science park (French Riviera), and an additional office is located in Besançon, allowing a close collaboration with the French public research institute.

• SENSeOR comprises 19 employees, with a majority of PhD.

• Total income mainly in France. Expanding sales to Germany, Italy, USA / Canada

• Our business model:– Sales of custom-designed systems– Sales of standard products: SAW temperature sensors, SAW readers…

January 2010 Page 27

SENSeOR’s expertises

• SENSeOR’s expertises cover every phase of your project: – Study and consultancy: evaluation of fit with your requirements, use

of unique simulation tools for fastest time-to-market, starter kits for immediate tests in your configuration

– Development and integration: from components to complete systems, with assistance for validation and integration in your application, protected by patents

– Custom solutions for production: from low to high volumes production capabilities through ISO TS certified partners, insurance of multiple sourcing

January 2010 Page 28

Leading capabilities

• Unique simulations tools

• Extensive portfolio of technology bricks and IP

• Strong partnerships with leading research institutes and founders

• Effective development kits

• Strong technical support

January 2010 Page 29

Conclusion

• SAW sensors offer a technological breakthrough: – Small, passive, wireless– Compatible with use in severe environments and/or on moving objects– Reliable, cost effective

• SAW sensors are already used in commercial applications: – SAW temperature sensors for diesel engines – SAW stress sensors– SAW chemical and biological sensors

• Senseor has the objective of being your industrial partner to deliver the promise of SAW sensors

January 2010 Page 30

www.senseor.com