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Transient electronics are an emerging technology for civilian and government applications that require controlled disintegration of an electronic chip into smaller components, by physical or chemical means. Here, a pillar‐on‐polymer architecture is presented for a transient system where the electronic components are partitioned on an array of silicon pillars. The pillars are mechanically tethered...
We present a zero-power multi sensor node integrated with a nanowatt power CMOS classifier. The vibration, acoustic, magnetic, rotation, and accelerometer sensors utilize lateral bimorphs as motion sensors. The sensor node is contained in a single enclosed package which serves as both the housing for the sensors but also as a Helmholtz resonator, providing increased signal at frequencies of interest...
One of the primary motivations for using ultrasound reflectometry for fingerprint imaging is the promise of increased spoof resistance over conventional optical or capacitive sensing approaches due to the ability for ultrasound to determine the elastic impedance of the imaged material. A fake 3D printed plastic finger can therefore be easily distinguished from a real finger. However, ultrasonic sensors...
In this paper an ultrasonic reflectometry approach to measure the thermal conductivity and temperature of a material by contact is presented. This device can be utilized for monitoring material properties during manufacturing, and robotic handling of objects. The sensor comprises an AlN piezoelectric ultrasonic transducer operating at GHz frequencies, situated on one side of a silicon chip. The transducer...
Surface acoustic wave (SAW) sensors offer mechanical motion in MHz to GHz range and energy can be confined to the surface to reduce boundary losses. A key challenge in implementing SAW based sensors is to improve the sensitivity of the measured SAW. A significant issue in SAW sensors is the source capacitance of IDTs, which makes parasitic capacitance and IDT size reduction a great burden on the SNR...
An ultrasonic motor is demonstrated that utilizes novel X-motion PZT bimorphs to drive the rotor. Laser manufactured piezoelectric actuators are demonstrated that produce bimorph tip motion from top-left to bottom-right, and from top-right to bottom-left in the shapes of the letter X. This is achieved by applying voltage amplitudes and phases to produce stresses that lead to both in-plane and out-of-plane...
Surface acoustic wave gyroscopes are a solution for inertial navigation applications which require operability through high levels of shock and vibration. Integration of multiple axis gyroscopes in a small device are also needed to reduce the size and weight of the sensor system. Here we present a two-axis SAW gyroscope using bulk excited surface wave through the Lithium Niobate wafer. For the bulk...
One of the primary motivations for using ultrasound reflectometry for fingerprint imaging is the promise of increased spoof resistance over conventional optical or capacitive sensing approaches due to the ability for ultrasound to determine the elastic impedance of the imaged material. A fake 3D printed plastic finger can therefore be distinguished in impedance compared to tissue. However, ultrasonic...
SAW sensors offer a mechanical motion in MHz to GHz range and can be immune to effects from boundary loss through the bulk and edges. SAW based gyroscopes have been implemented by added masses which impose an effect on wave prorogation fronts through the Coriolis force. A key challenge in implementing SAW based gyroscopes is to improve the sensitivity owing to small forces and SAW signals. significant...
Unreleased gyroscopes are very promising for inertial navigation systems, where the extended dynamic range and structural robustness are not only desirable but expected for many applications. Surface acoustic wave (SAW) gyroscopes, having solid structure, offer high shock survivability and by confining acoustic energy to the surface, may lead to increased sensitivity by avoiding losses to the bulk...
Ultrasonic motors generally require high contact force to clamps surfaces. These surfaces are actuated by high forces generated by ultrasonic transducers, typically operating at resonance frequencies. Many actuator types have been explored, the most common being out-of-plane bimorphs. In this paper, we implement a motor utilizing an array of lateral PZT bimorphs. The lateral bimorphs, with vertical...
In many cases it is important to measure the temperature and the thermal conductivity of an object by contact. Examples include sensors in robot hands, and sensors to measure material properties during manufacturing. In this paper, we demonstrate the ability to measure the time-of-flight (TOF) as a function of time after mechanical contact to the transducer, and show that the rate of TOF change can...
Integrated GHz ultrasonics on planar systems such as CMOS chips are enabled by integration of fast, deep sub-micron transistors and GHz thin film piezoelectric transducers. Precision and stability in a delay element block is one of the key specifications that directly impacts all the applications. We have implemented a pulse-echo transmit-receive ultrasonic delay element that is stable over time and...
We present an ultrasonic pulse delay-based oscillator with a temperature coefficient profile that can be programmed through layout or choice of excitation frequency. A zero temperature coefficient can be achieved at certain temperature ranges The oscillator utilizes the propagation delay of GHz wave packets traveling through the silicon bulk, generated and received by piezoelectric aluminum nitride...
This paper reports a mechanical stage with 3-axis angular dither capability used to calibrate 3-axis gyroscope chip. A combination of piezoelectric and magnetic actuation provides in-plane and out-of-plane motion. The 3-axis dither capability is crucial for fully calibrating the scale factor and bias of a commercial 3-axis MEMS gyroscope. The measured magnetically actuated dither stage scale factor...
This work presents frequency tuning and quadrature cancellation of a bulk-PZT gyroscope. We leverage non-linearity of elasticity and piezoelectric coupling in lateral PZT bimorphs for frequency and quadrature tuning. Frequency and quadrature tuning is demonstrated with an applied DC voltage, as a broadband control for potential closed loop operation. Resonance and quadrature tuning of ∼10ppm/Vdc and...
The near zero-power sensor node solution is presented with piezoelectric sensors and DC tunable threshold electrostatic switches. A sensor suite measuring acceleration, rotation, and magnetic field based on PZT lateral bimorphs is used with NEMS switches for the detection of a desired signal pattern and generating a wake up trigger. The sensors are capable of detecting physical signals from 5 Hz to...
We report on a 1D linear array of GHz ultrasonic transducers as an ultrasonic impedance imager for fingerprint sensing. This device is based on an all solid state aluminum nitride (AlN) transducer array that eliminates the need for released membranes. Compared to lower frequency (10–50 MHz) ultrasonic sensors, our device uses GHz ultrasonic pulses, generated by driving AlN pixel transducers at resonance...
Precise timing and frequency sources are vital in a wide range electronic-based systems such as communication networks and global positioning systems. These applications constantly demand reductions in size, weight and power (SWaP) while improving the precision of time or frequency references. Historically, clocks based on electromagnetic oscillations of atoms have provided the most precise method...
Transient materials, or materials with designed short lifetimes, are of great interest in many fields of research. This work describes the development of polycarbonates as a thermally-triggered vaporizable substrate platform. Good mechanical properties over operational temperature ranges in combination with fast and clean decomposition at slightly higher temperatures create an effective transient...
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