Why Use SAW Sensors and Tags? - Frequency/time are measured with greatest accuracy compared to any other physical measurement (10-10 - 10-14). - External stimuli affects device parameters (frequency, phase, amplitude, delay) - Operate from cryogenic to >1000oC - Ability to both measure a stimuli and to wirelessly, passively transmit information - Frequency range ~10 MHz – 3 GHz - Monolithic structure fabricated with current IC photolithography techniques, small, rugged

8. Applications of SAW Devices Military (continued) A Few Examples Military Applications Functions Performed Radar Pulse Compression Pulse Expansion and Compression Filters ECM Jammers Pulse Memory Delay Line ECCM Direct Sequence Spread Spectrum- Fast Frequency Hopping- Pulse Shaping, Matched Filters, Programmable Tapped Delay Lines, Convolvers, Fast Hop Synthesizer Fast Hop Synthesizer Ranging Pulse Expansion & Compression Filters

9. SAW 7 Bank Active Channelizer From Triquint, Inc.

10. Applications of SAW Devices A Few Examples Consumer Applications Functions Performed TV IF Filter Cellular Telephones RF and IF Filters VCR IF Filter & Output Modulator Resonators CATV Converter IF Filter, 2 nd LO & Output Modulator Resonators Satellite TV Receiver IF Filter & Output Modulator

11. VSB Filter for CATV - Sawtek Bidirectional Transducer Technology – IF Filter w/ moderate loss; passband shaping and high selectivity.

12. Basic Wave Parameters Waves may be graphed as a function of time or distance. A single frequency wave will appear as a sine wave in either case. From the distance graph the wavelength may be determined. From the time graph, the period and frequency can be obtained. From both together, the wave speed can be determined. Velocity*time=distance Velocity=distance/time= The amplitude of the wave can be absolute, relative or normalized. Often the amplitude is normalized to the wavelength in a mechanical wave. A=0.1*wavelength

13. SAW Advantage

15. Piezoelectricity (pie-eezo-e-lec-tri-ci-ty)

16. SAW Transducer

17. Surface Wave Particle Displacement SAW is trapped within ~ 1 wavelength of surface

18. Schematic of Apodized SAW Filter 2mm 10mm Quartz Filter

19. SAW Filter Fabrication Process Trim (if necessary) Dice Clean Final Trim Package

20. Mask Structure Device Features 2.5mm 10mm LiNbO 3 Filter

21. Fabrication – Electrode Widths From: Siemens

22. RF Probe Station with Temperature Controlled Chuck for SAW Device Testing RF Probe and ANA Top view of chuck assembly with RF probes

23. Response of SAW Reflector Test Structure Measurement of S 21 using a swept frequency provides the required data. Transducer response Reflector response is a time echo which produces a frequency ripple

24. SAW OFC Device Testing RF Wafer Probing Actual device with RF probe

31. University of Central Florida School of Electrical Engineering and Computer Science Schematic of OFC SAW ID Tag Example OFC Tag

32. S 11 of SAW OFC RFID – Target Reflection S 11 w/ absorber and w/o reflectors University of Central Florida School of Electrical Engineering and Computer Science SAW absorber

33. Dual-sided SAW OFC Sensor

35. SAW Velocity vs Temperature

36. OFC SAW Dual-Sided Temperature Sensor University of Central Florida Department of Electrical and Computer Engineering

37. Temperature Sensor using Differential Delay Correlator Embodiment University of Central Florida School of Electrical Engineering and Computer Science Temperature Sensor Example 250 MHz LiNbO 3 , 7 chip reflector, OFC SAW sensor tested using temperature controlled RF probe station

39. Effect of Code Collisions from Multiple SAW RFID Tags -Simulation Due to asynchronous nature of passive tags, the random summation of multiple correlated tags can produce false correlation peaks and erroneous information University of Central Florida School of Electrical Engineering and Computer Science

41. 456 MHZ SAW OFC TDD Coding University of Central Florida School of Electrical Engineering and Computer Science A 456 MHz, dual sided, 5 chip, tag COM-predicted and measured time responses illustrating OFC-PN-TDD coding. Chip amplitude variations are primarily due to polarity weighted transducer effect and fabrication variation.

43. 32 Sensor Code Set - TDD Optimized Not Optimized Receiver Correlation Receiver Antenna Input

44. Chirp Interrogation Synchronous Transceiver- Software Radio Approach University of Central Florida Department of Electrical and Computer Engineering

45. 250 MHz OFC TxRx Demo System Synchronous TxRx SAW OFC correlator prototype system RF clock section Digital section University of Central Florida School of Electrical Engineering and Computer Science Wireless 250 MHz SAW OFC temperature test using a free running hot plate. The red dashed curve is a TC and the solid blue curve is the SAW extracted temperature. ADC & Post processor output

46. WIRELESS SAW TEMPERATURE SENSOR DEMONSTRATION Real-time wireless 250 MHz SAW OFC temperature test using a free running hot plate. The red dashed curve is a TC and the solid blue curve is the SAW extracted temperature. Post processor output

47. 915 MHz Transceiver System

55. OFC Cryogenic Sensor Results University of Central Florida School of Electrical Engineering and Computer Science Scale Vertical: +50 to -200 o C Horizontal: Relative time (min) Measurement system with liquid nitrogen Dewar and vacuum chamber for DUT OFC SAW temperature sensor results and comparison with thermocouple measurements at cryogenic temperatures. Temperature scale is between +50 to -200 o C and horizontal scale is relative time in minutes.

58. Measured E-Beam Evaporated Palladium Conductivity v Film Thickness Conductivity measurements made in-situ under vacuum σ inf = 9.5·10 4 S/cm

67. Plot generated by ANSYS demonstrating the strain distribution along the z-axis of the crystal. Test fixture, this shows the surface mount package, which contains the cantilever device, securely clamped down onto a PC board which is connected to a Network Analyzer. OFC Cantilever Strain Sensor