Delivering the Promise of Surface Acoustic Wave Sensors

1. Delivering the Promise of Surface Acoustic Wave Sensors

2. What’s a wireless and passive sensor? « Standard » wireless sensor • SAW wireless AND passive sensor

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)

4. How it works!

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

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)

7. Principle of SAW interrogation discharge charge 1. RF Pulse sent to the resonators 2. Load of the resonators 3. Answer from the resonators 4. Answer analysis Interrogator Interrogator Sensor Sensor P, T, ID, etc.

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)

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 : • D(f3-f2)  information about pressure variations • D(f1-f2)  information about temperature variations • Other types of structures can be used according to the pressure measurement range, in particular for high pressure

10. Frequency response of a SAW pressure sensor F1 (red) F2 (green) F3 (blue) Example of frequency response of a SAW pressure sensor at 434MHz (frequency variations from 0 to 5bars)

11. SAW Delay Lines • 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)

12. The products and applications

13. Green technology Our offer to your applications Unique sensing solutions Technology & CoreBenefits Applications Rotating and moving parts Inside engines, turbines, pumps, tyres, gearboxes… Harsh environments High temperatures (ovens…), strong electromagnetic fields (HV breaker boxes…), explosive atmospheres… Confined places Inside materials (concrete, plastic,…), underground pipes, tanks, industrial valves… Temperature Stress, Pressure Wireless Batteryless Works where no others work High performance, cost effective Others to come (e.g. chemical) Compact , Robust

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

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 sensors Left : SAW temperature sensor 5x5mm Middle : SAW stress resonator 7x5.2mm Right : SAW temperature sensor (delay line) 9x3.8mm Meander antenna at 434MHz 3 cm 11 cm

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

17. Configuration with fixed interrogator linked to a PC • Possible interfaces: • Wireless (Zigbee, Bluetooth…) • Analog (0-5Volt) • RS232 / USB • CANBus… SAW sensor Fixed reader connected through RS232 to a PC (IHM software supplied to monitor real-time measurements)

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)

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

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…)

21. SAW Temperature Evaluation kit – SAW TDK1 SAW sensor in thermowell packaging with antenna (SED100) SAW sensor probe (6mm diameter) with antenna – SED120 SAW sensor with PIFA antenna for temperature monitoring of surface SAW reader V3.3 with monopole antenna and USB connection

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

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)

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

25. The Company

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…

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

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

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

30. www.senseor.com