novel narrowband acoustic sensors for sub-ghz
TRANSCRIPT
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Novel narrowband acoustic sensors for sub-GHzISM compliant wireless measurements
D. Rabus 1, T. Barron 1, E. Lebrasseur 1, S. Alzuaga 1, G. Martin 1,J.-M Friedt 2, S. Ballandras 1,2
1 FEMTO-ST Time & frequency dpt., UMR 6174 CNRS, Besancon, France2 SENSeOR SAS, Besancon, France
Contact: {jmfriedt,ballandr}@femto-st.frslides available at http://jmfriedt.free.fr
October 29, 2011
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
High-overtone Bulk AcousticResonator (HBAR): basics
Objective: robust structure for high frequency/high Q resonators
Mechanical structure: stack of single-crystal piezoelectric layer + lowacoustic loss substrate ⇒ robust structure (� FBAR) while reachinghigh frequency (thin piezo layer)
Issues:
• thin single-crystal piezoelectric layer 1
• wafer scale assembly, 2
• low acoustic loss adhesion strategy,
• reaching the buried electrode
1T. Baron, D. Gachon, G. Martin, S. Alzuaga, D. Hermelin, J.-P. Romand, S.Ballandras, Temperature Compensated Radio-Frequency Harmonic Bulk AcousticResonators, Proceedings of IEEE International Frequency Control Symposium (2010)
2T. Baron, D. Gachon, J.-P. Romand, S. Alzuaga, S. Ballandras, J. Masson, L.Catherinot, M. Chatras, A Pressure Sensor Based on a HBAR MicromachinedStructure, Proceedings of IEEE International Frequency Control Symposium (2010)
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
High-overtone Bulk AcousticResonator (HBAR): expected
responseCoupled resonators between the thin piezoelectric film and low acousticloss (thick) substrate
0
0.2
0.4
0.6
0.8
1
0 200 400 600 800 1000
Y (
a.u
.)
frequency (MHz)
MATERIAL 1
Adhesion layer
Electrode
(low acoustic
losses)
MATERIAL 2
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
High-overtone Bulk AcousticResonator (HBAR): expected
responseCoupled resonators between the thin piezoelectric film and low acousticloss (thick) substrate
0
0.2
0.4
0.6
0.8
1
0 200 400 600 800 1000
Y (
a.u
.)
frequency (MHz)
e
f=n.V/(2.e)
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Manufacturing flowchart
piezoelectric
material
low acoustic
loss material
Au
grinding &
polishing
low acoustic
loss material
Au
piezoelectric
electrode
patterning
low acoustic
loss material
Au
piezoelectric
1 4” wafer scale process
2 room temperature gold-eutectic bonding (high pressure)
3 if no access to buried electrode, coupled resonators
4 small resulting dimension (<1 mm×1 mm)
5 bulk electrode ⇒ reduced aging and influence of environment (w.r.tIDTs)
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Interrogation strategies• Closed loop (oscillator) is challenging due to the multimode
response• Open-loop interrogation strategy suitable for this multimode
transducer• Fourier transform of a frequency comb is a series of time-domain
pulses ⇒ can be used either as a narrowband transducer (frequencydomain) or a wideband, multimode device (time domain)
0
500
1000
1500
2000
0 0.5 1 1.5 2 2.5 3
Y (
a.u.
)
time (us)
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Frequency v.s physical quantity(sensor)
• Stack of single-crystal materials ⇒ accurate simulation of thermalbehaviour (expansion coefficients)⇒ design of either temperature compensated device or temperaturesensor (mixed matrix simulation)
• Interrogation range limited by resonator Q (energy storage) andreceiver detection limit (LNA & power detector noise)
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
100 200 300 400 500 600 700 800
imag
(Y)
(S/m
2)
freq (MHz)
0
2e+06
4e+06
6e+06
8e+06
1e+07
1.2e+07
1.4e+07
100 200 300 400 500 600 700 800
real
(Y)
(S/m
2)
temperature dependence as a function of overtone number static capacitance
(varying LNO (YXl/163o )/quartz thickness ratios)
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Frequency v.s physical quantity(sensor)
• Stack of single-crystal materials ⇒ accurate simulation of thermalbehaviour (expansion coefficients)⇒ design of either temperature compensated device or temperaturesensor (mixed matrix simulation)
• Interrogation range limited by resonator Q (energy storage) andreceiver detection limit (LNA & power detector noise)
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Wireless measurement (frequency)Measurement strategy: frequency sweep-monostatic RADARinterrogation
offset
& gain
PA
power
detector
AD9954 DDS
frequencysweep
434+/−1 MHz
434+/−1 MHzAD8302
duplexer
switchARM7
1MS/s ADCUART SPI
microcontroller
1 program frequency synthesizer (AD9954) at frequency f
2 send RF pulse for a duration longer than Q/(πf ) s (resonator load)
3 switch antenna from emission (synthesizer + power amplifier) to reception (lownoise amplifier + power detector)
4 record magnitude of returned signal (wideband power detector) within thefrequency interrogation range after a duration � Q/(πf ) (resonator energyrelease)
5 f → f + ∆f & repeat for all values of f in interrogation band 3 4
3J.-M Friedt, C. Droit, G. Martin & S. Ballandras, A wireless interrogation system exploiting narrowband acoustic resonator for
remote physical quantity measurement, Rev. Sci. Instrum. 81, 014701 (2010)4
C. Droit, G. Martin, S. Ballandras & J.-M Friedt, A frequency modulated wireless interrogation system exploiting narrowbandacoustic resonator for remote physical quantity measurement, Rev. Sci Instrum. 81 (5), 056103 (2010)
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Wireless measurement (frequency)
Experimental setup: SENSeOR interrogation unit programmed to probe432-434 MHz range (128 frequency steps), 16 averages(' 120 ms/measurement)
wideband narrowband
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Wireless measurement (frequency)
Experimental setup: SENSeOR interrogation unit programmed to probe432-434 MHz range (128 frequency steps), 16 averages(' 120 ms/measurement)
Experimental setup selected resonanceat 431.92495 MHz
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Wireless measurement (frequency)
⇒ resulting signal is a curve of returned power as a function offrequency f , with maxima close to each resonance frequency
4.31905e+08
4.3191e+08
4.31915e+08
4.3192e+08
4.31925e+08
4.3193e+08
4.31935e+08
0 50 100 150 200 250 300 350 400 450
freq
uenc
y (H
z)
time (a.u.)
⇒ after removing measurements with excessive standard deviationamongst the 16 measurements (28% of the dataset, red): σf = 1800 Hz
(if 1.7 MHz bandwidth allows for 170 K temperature span, 10 kHz/K and
σf = 1800 Hz∼ σT = 0.2 K)
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Wireless measurement example
Measurement example: one resonance frequency as a function oftemperature, for one temperature compensated HBAR (black) and onetemperature sensivite HBAR (sensor: green & blue): wireless,f ∈ [431− 343] MHz.
⇒ differential frequency measurement strategy available (reduces sensorand local oscillator aging drift + correlated noise sources)
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Wireless measurement (time)
• Wideband RF pulseilluminates dielectricinterfaces & theHBAR sensor,
• bistaticconfiguration,
• basebandmeasurement ⇒amplitude and phaseinformations,
• demonstration usingunmodifiedcommercial GroundPenetrating RADAR(GPR) :Mala RAMAC
at constant
wavelength
GPR operates
pulse
high voltage
dipole antenna dipole antenna
dielectric interface
as cooperative target
passive sensor acting
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Wireless measurement (time)• Resonance over a wide frequency range ⇒ the same HBAR is
compatible with multiple RADAR frequencies (in GPR: defined byantenna dimensions)
• here all reflections are from the same acoustic mode: a sensor willrequire different modes exhibiting different sensitivities with respectto the physical quantity under investigation
-2500
-2000
-1500
-1000
-500
0
500
0 5e-07 1e-06 1.5e-06 2e-06 2.5e-06
retu
rned
pow
er (
a.u.
)
time (s)
200 MHz antenna
-2500
-2000
-1500
-1000
-500
0
500
0 5e-07 1e-06 1.5e-06 2e-06 2.5e-06
retu
rned
pow
er (
a.u.
)
time (s)
100 MHz antenna
Left: the same HBAR probed
with a GPR equipped with 100
(top) and 200 MHz (bottom)
antennas
IEEE Sensors 2011
Novelnarrowband
acoustic sensorsfor sub-GHz ISM
compliantwireless
measurements
Ballandras & al.
HBAR basics
Manufacturing
Wirelessinterrogation
Conclusion
Conclusion• Wafer scale manufacturing process of high Q multimode resonators,
• used as passive sensors compatible with time domain (wideband) &frequency domain (narrowband) wireless interrogation,
• demonstrated interrogation range of ' 1 m using a frequency sweepmonostatic switched RADAR strategy, or 100 & 200 MHzcommercially available Ground Penetrating RADAR
• single crystal materials ⇒ detailed modelling (mixed matrix),including thermal behaviour,
• ability to select materials and cuts in order to achieve temperatureturnover within the measurement range (reference device) or hightemperature drift (sensor),
• tiny dimensions (<1 mm×1 mm)
Contact: [email protected] Sensors 2011