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A Bulk Acoustic Wave (BAW) Based Transceiver for an In-Tire-Pressure Monitoring Sensor Node
Abstract
Attaching a tire pressure monitoring system (TPMS) on the inner liner of a tire allows sensing of important additional technical parameters, such as vehicle load or tire wearout. The maximum weight of the sensor is limited to 5 grams including package, power supply, and antenna. Robustness is required against extreme levels of acceleration. The node size is limited to about 1 cm3 to avoid high force-gradients due to device-deformation and finally, a long power supply lifetime must be achieved. In this paper a low-power FSK transceiver is presented. Exploiting BAW resonators the use of a bulky and shock-sensitive crystal and a PLL can be avoided. This makes the system more robust and radically reduces the start-up time to 2 ¿s from few ms as in state-of-the-art crystal oscillator based systems. The current consumption of the transceiver is 6 mA in transmit mode with a transmit output power of 1 dBm and 8 mA in receive mode with a sensitivity of -90 dBm at a data rate of 50 kBit/s and a bit error rate of 10<sup>-2</sup>. The transceiver ASIC and a microcontroller ASIC, a MEMS sensor, and a BAW die are arranged in a 3-D chip stack for best compactness, lowest volume, and highest robustness. The sensor node allows sensing of pressure, acceleration, supply voltage and temperature.
... Also, due to a high f×Q inherent in MEMS, excellent phase noise performance can be 11 obtained with a low-power oscillator design. Reported works have demonstrated MEMSbased low-power radio transceivers with frequency-shift keying (FSK) modulation [17] and on-off keying (OOK) modulation [18]. Some other innovative implementations include the use of a super-regenerative MEMS oscillator to directly sample at RF for a low-power receiver implementation [18]. ...
... 5. A PLL-less frequency synthesizer using a MEMS-based digital-controlled oscillator for wake-up radios[17]. ...
... 17. Temperature increase of the active area in the platform versus heater power extracted from measurement. ...
Microelectromechanical systems (MEMS) have great potential in realizing chip-scale integrated devices for energy-efficient analog spectrum processing. This thesis presents the development of a new class of MEMS resonators and filters integrated with CMOS readout circuits for RF front-ends and integrated timing applications. Circuit-level innovations coupled with new device designs allowed for realizing integrated systems with improved performance compared to standalone devices reported in the literature.
The thesis is comprised of two major parts. The first part of the thesis is focused on developing integrated MEMS timing devices. Fused silica is explored as a new structural material for fabricating high-Q vibrating micromechanical resonators. A piezoelectric-on-silica MEMS resonator is demonstrated with a high Q of more than 20,000 and good electromechanical coupling. A low phase noise CMOS reference oscillator is implemented using the MEMS resonator as a mechanical frequency reference. Temperature-stable operation of the MEMS oscillator is realized by ovenizing the platform using an integrated heater. In an alternative scheme, the intrinsic temperature sensitivity of MEMS resonators is utilized for temperature sensing, and active compensation for MEMS oscillators is realized by oven-control using a phase-locked loop (PLL). CMOS circuits are implemented for realizing the PLL-based low-power oven-control system. The active compensation technique realizes a MEMS oscillator with an overall frequency drift within +/- 4 ppm across -40 to 70 ??C, without the need for calibration. The CMOS PLL circuits for oven-control is demonstrated with near-zero phase noise invasion on the MEMS oscillators. The properties of PLL-based compensation for realizing ultra-stable MEMS frequency references are studied.
In the second part of the thesis, RF MEMS devices, including tunable capacitors, high-Q inductors, and ohmic switches, are fabricated using a surface micromachined integrated passive device (IPD) process. Using this process, an integrated ultra-wideband (UWB) filter has been demonstrated, showing low loss and a small form factor. To further address the issue of narrow in-band interferences in UWB communication, a tunable MEMS bandstop filter is integrated with the bandpass filter with more than an octave frequency tuning range. The bandstop filter can be optionally switched off by employing MEMS ohmic switches co-integrated on the same chip.
... A third sensor network measures the seismic activity on bridges and other structures for infrastructure health monitoring [11]. A final group has developed an in-tire pressure monitor to measure vehicle load and tire wear-out [12]. Due to the gradient forces inside the wheel well, the size of the node is restricted to a volume of approximately 1cm 3 . ...
... One possible concern is the integrated circuit (IC) components. Fortunately, modern CMOS ICs, with the help of process scaling, are capable of providing the desired circuit functionality while still fitting within a cubic-mm form-factor [12]- [19]. To further reduce area requirements, several IC blocks can be integrated onto a single die to create a system-on-chip (SoC) [14], [19]. ...
... Cubic-millimeter wireless sensor nodes with long lifetimes are desired for many applications. Unfortunately, many current sensor nodes [3]- [7] have a volume of on the order of 10cm 3 to 100cm 3 , giving them many design attributes consistent with the Communication Radio 400µW-29mW [12], [14], [28], [58], [59] smartphone class of computers. In effect, these sensor nodes are just the first step toward the smaller, more pervasive computers envisioned for wireless sensor networks. ...
Society has been witness to and participant in an on-going computing revolution as new classes of computing technology have displaced older technologies as the dominant market force--from mainframes decades ago to smartphones today. The rise of each new class of computing technology has brought about even smaller and more ubiquitous systems. As this trend continues, wireless sensor networks (WSNs) are widely perceived as the new frontier of computing technology for a variety of applications, including environmental, infrastructure, and health monitoring. Many of these applications, however, require sensor nodes with both long lifetimes and small volumes, resulting in highly energy-constrained systems. Because energy sources, such as a battery and solar cell, have been slow to improve, energy must instead be conserved through better circuit design and systems analysis. While significant progress has been made in low-power processors and timers, wireless synchronization and communication remain the highest energy tasks in a wireless sensor node.
In this dissertation, the design of three RF integrated circuits is presented to address challenges associated with synchronization and communication in WSNs. Two of these circuit designs demonstrate a new type of receiver for harvesting a digital clock from ambient wireless signals for the synchronization of a WSN. The first receiver extracts a clock from the GSM standard while the other extracts a clock from the CDMA standard. Both receivers are designed with a low-power sleep-state so they can be duty-cycled to further conserve synchronization energy. Several other wireless standards also are investigated for their potential as a harvested-clock source.
The third circuit design demonstrates a 10GHz IR-UWB receiver for cubic-mm sensor nodes based on a new communication protocol which is also presented. The protocol enables the duty-cycled operation of a communication radio in severely energy-constrained systems and takes into account system-level challenges like battery limitations and clock accuracy. Based on this analysis, a receiver architecture was developed that satisfies all of the constraints for a cubic-mm system.
... However, these feedback techniques could be costly to the power budget. Instead, a nice solution is to use a diode-connected PMOS "active inductor" similar to that presented in [44,45]. Doing so allows the NMOS current mirror to set the bias, however, the frequency response of the active inductor should be tuned to improve Ideally the pole should take effect at a lower frequency than the zero to minimize the undesired impedance, however, gm,p and RB cannot be significantly reduced for the reasons discussed above. ...
... IC fabrication[59], flip-chip bonding[60], and through-silicon-vias[45]. But with an eye on cost and size minimization, an imporant direction for research in MEMSbased transceivers is total integration of RF-MEMS resonators with standard CMOS processes [61, 62]. ...
In recently published integrated medical monitoring systems, a common thread is the high power consumption of the radio compared to the other system components. This observation is indicative of a natural place to attempt a reduction in system power. Narrowband receivers in-particular can enjoy significant power reduction by employing high-Q bulk acoustic resonators as channel select filters directly at RF, allowing down-stream analog processing to be simplified, resulting in better energy efficiency. But for communications in the ISM bands, it is important to employ multiple frequency channels to permit frequency-division-multiplexing and provide frequency diversity in the face of narrowband interferers. The high-Q nature of the resonators means that frequency tuning to other channels in the same band is nearly impossible; hence, a new architecture is required to address this challenge. A multi-channel ultra-low power OOK receiver for Body Area Networks (BANs) has been designed and tested. The receiver multiplexes three Film Bulk Acoustic Resonators (FBARs) to provide three channels of frequency discrimination, while at the same time offering competitive sensitivity and superior energy efficiency in this class of BAN receivers. The high-Q parallel resonance of each resonator determines the passband. The resonator's Q is on the order of 1000 and its center frequency is approximately 2.5 GHz, resulting in a -3 dB bandwidth of roughly 2.5 MHz with a very steep rolloff. Channels are selected by enabling the corresponding LNA and mixer pathway with switches, but a key benefit of this architecture is that the switches are not in series with the resonator and do not de-Q the resonance. The measured 1E-3 sensitivity is -64 dBm at 1 Mbps for an energy efficiency of 180 pJ/bit. The resonators are packaged beside the CMOS using wirebonds for the prototype.
... Recently, a good deal of research has addressed the possibility of using BAW resonators and filters for other applications: low phase noise oscillators [1] [2], narrow-band single-channel receivers [3] [4], power amplification [5], etc. The aim of this work is to propose a new class of applications based on BAW resonators: low power, narrow-band filters. ...
... This work is original in that it associates the design of the BAW filter with that of the surrounding circuitry while taking into account the design constraints of both. Also, the use of a filter (i.e. a combination of resonators) versus the use of a single resonator topology as in [3] [4] greatly improves the achievable selectivity. Finally, the filter design methodology described is based on existing BAW resonator technologies and fabrication processes and therefore does not depend on the development of new resonator process flows. ...
This paper presents an original method for the design of Bulk Acoustic Wave (BAW) filters for a new class of applications: ultra-low-power, narrow-band RF filtering. To this end, a filter co-design methodology, based on existing BAW resonator technology and fabrication processes, is developed and the link between decreasing filter bandwidth and decreasing power consumption of the associated integrated circuit is demonstrated. Depending on required bandwidth, the power dissipation of the driving electronics can be reduced by large factors (10 to 40). Applications to High-IF receivers and Wake-up receivers are described.
... Therefore, Tire-pressure monitoring should be the fundamental function of an intelligent tire. Tire-pressure monitor systems (TPMSs) are widely used all over the world [32,33]. ...
An intelligent tire uses sensors to dynamically acquire or monitor its state. It plays a critical role in safety and maneuverability. Tire pressure is one of the most important status parameters of a tire; it influences vehicle performance in several important ways. In this paper, we propose a tire-pressure identification scheme using an intelligent tire with 3-axis accelerometers. As the primary sensing system, the accelerometers can continuously and accurately detect tire pressure with less electronic equipment mounted in the tire. To identify tire pressure in real time during routine driving, we first developed a prototype for the intelligent tire with three 3-axis accelerometers, and carried out data-acquisition tests under different tire pressures. Then we filtered the data and concentrated on the vibration acceleration of the rim in the circumferential direction. After analysis, we established the relationship between tire pressure and characteristic frequency of the rim. Finally, we verified our identification scheme with actual vehicle data at different tire pressures. The results confirm that the identified tire pressure is very close to the actual value.
... Aimed at providing advanced sensing information and control technologies related to different transportation modes and even vehicle monitoring, the tire pressure monitor is deemed one of the three major safety systems in automobiles. [30][31][32][33][34][35][36] The first tire pressure monitoring system operates by comparing rotation rates of four wheels. Once one of the wheels differs from others in rate, the trip-computer system will give an alarm. ...
Tire pressure monitoring plays a pivotal role in vehicle safety system. However, as a conventional battery‐operated electronic system, regularly replacing battery remains a great inconvenience in wide‐distributed tire pressure sensing. Here, we introduce a self‐powered tire pressure monitor by using a rotary cylinder‐based hybrid nanogenerator as a sustainable power source. The designed energy harvester, by hybridizing a triboelectric nanogenerator (TENG) and electromagnetic generator (EMG), can scavenge rotational energy from rolling axles. Integrating with transformers, the hybrid nanogenerator can achieve an open‐circuit voltage of 16 V and short‐circuit current of 0.1 mA at the rotation rate of 150 rpm, respectively, with the maximal output power of about 1.8 mW at the loading of 20 kΩ. Via a programmable software, the hybrid device can operate as a self‐powered counter and timer for potential speed detecting. Further, it has been demonstrated that the hybrid nanogenerator is capable of triggering a transmitter‐integrated tire pressure sensor for self‐powered monitoring tire pressure in real time. This study expands applications based on TENGs in automobile engineering, which might promote the development of intelligent driving and traffic safety engineering. We have demonstrated a cylinder‐based hybrid rotary nanogenerator that can grab rotational energy and serve as a sustainable power source. Besides, it has been proved the hybrid nanogenerator is capable of triggering a trasnsmitter‐integrated tire pressure sensor for self‐powered monitoring real‐time tire pressure.
... Here, MEMS and IC devices are integrated with a broad spectrum of other basic technologies, ranging from optics and power electronics to wireless components, in a common package 2 . As shown in Figure 5, complete sensor nodes comprising chip-level MEMS, ASIC, wireless communication and power management components are 3D integrated at the package level 62,63 . In summary, the key advantages of multi-chip solutions are their modularity, high flexibility and reasonably low fabrication complexity. ...
... Batteries are not feasible in many applications because of their lifetime, weight, size, safety and for use in remote locations. There are emerging applications such as biomedical drug-delivery implants, implantable medical electronic devices and wireless micro-sensor networks, where conventional batteries are impractical because of the difficulty in replacing the batteries [25][26][27][28]. Several energy sources such as solar, thermal and mechanical energy can be used as sources of energy in self-powered devices. ...
This review will highlight recent research underlying the design of novel nanodevices and nanosensors that incorporate graphene, nanodots, nanowires, and biomolecules including DNA aptamers and peptides. The emphasis is on models and theory that guide the design of these nanodevices and nanosensors. In selected cases, research designed to test the usefulness of these designs is highlighted in this chapter.
... Battery-less TPMSs usually refers to remotely powered systems (passive TPMS), but also can be used to describe a TPMS powered by energy harvesting. The former has a hidden disadvantage; that is draining the vehicle battery [133], as remotely powering is actually using the vehicle battery and thereby they are technically battery powered. The latter is the type of TPMS that is legitimately battery-less, so called self-powered TPMS which is the target of this research. ...
This article presents an overview on the state of the art of Tyre Pressure Monitoring System related technologies. This includes examining the latest pressure sensing methods and comparing different types of pressure transducers, particularly their power consumption and measuring range. Having the aim of this research to investigate possible means to obtain a tyre condition monitoring system (TCMS) powered by energy harvesting, various approaches of energy harvesting techniques were evaluated to determine which approach is the most applicable for generating energy within the pneumatic tyre domain and under rolling tyre dynamic conditions. This article starts with an historical review of pneumatic tyre development and demonstrates the reasons and explains the need for using a tyre condition monitoring system. Following this, different tyre pressure measurement approaches are compared in order to determine what type of pressure sensor is best to consider in the research proposal plan. Then possible energy harvesting means inside land vehicle pneumatic tyres are reviewed. Following this, state of the art battery-less tyre pressure monitoring systems developed by individual researchers or by world leading tyre manufacturers are presented. Finally conclusions are drawn based on the reviewed documents cited in this article and a research proposal plan is presented.
... Many systems are changed from cable-based to wireless to save cables and thereby weight and in the end fuel. Examples are many comfortability systems like distance sensors or safety related systems like tire pressure monitoring [26, 27]. The data needed for central control is collected by numerous specialized sensors and transferred to the central unit or distributed local central units. ...
Previously mostly independently considered topics grow more and more together to form the building blocks of the future smart city. The building itself needs to be built as a zero average energy consuming building, posing requirements mainly on thermal and electrical parameters. Those parameters need to be known and controlled, requiring intelligent control techniques and cross-layer optimized sensor networks. Finally, very differently used buildings together participate in the infrastructure of the city, which gives them freedom to passively burden the grids, or actively help stabilizing them, while benefitting from different tariffs in the smart grids. This paper summarizes the state of the art of those topics with respect to industrial electronics.
... There are many current applications for pressure sensing devices in many industries. In the automotive industry, for example, a typical passenger car has pressure sensors in the powertrain, brake and airbag systems, in tire pressure monitoring, and increasingly in safety and ergonomic systems (Flatscher et al. 2010;Markle et al. 2004;Pavlin and Novak 2008). In the biomedical industry, pressure sensors find application in invasive and noninvasive monitoring of blood intracranial and epidural pressure as well as in dialysis and other external control systems (Ginggen et al. 2008;Kanellos et al. 2010;Wahab et al. 2009). ...
In this paper, a four-terminal piezoresistive sensor commonly known as a van der Pauw (VDP) structure is presented for its
application to MEMS pressure sensing. In a recent study, our team has determined the relation between the biaxial stress state
and the piezoresistive response of a VDP structure by combining the VDP resistance equations with the equations governing
silicon piezoresistivity and has proposed a new piezoresistive pressure sensor. It was observed that the sensitivity of the
VDP sensor is over three times higher than the conventional filament type Wheatstone bridge resistor. To check our theoretical
findings, we fabricated several (100) silicon diaphragms with both the VDP sensors and filament resistor sensors on the same
wafer so both the sensor elements have same doping concentration. Several diaphragms had VDP sensors of different sizes and
orientations to find out their geometric effects on pressure sensitivity. The diaphragms were subjected to known pressures,
and the pressure sensitivities of both types of sensors were measured using an in-house built calibration setup. It was found
that the VDP devices had a linear response to pressure as expected, and were more sensitive than the resistor sensors. Also,
the VDP sensors provided a number of additional advantages, such as its size independent sensitivity and simple fabrication
steps due to its simple geometry.
... Small sized shock-resistant BAW resonators are utilized as frequency reference for the TRX and channel selection filter in the receive chain [28]. A BAW resonator can be considered as a thin film of piezoelectric material sandwiched between two metal electrodes. ...
Using wireless communication and energy harvesting in automobiles might have significant advantages considering dependability (no wires and contacts) and weight (no cable tree). In this paper, we give a brief overview of the related technologies, surrounding conditions, and methods for design and optimization. As examples, we focus on methods for harvesting kinetic energy and wireless transmission in a tire pressure metering system (TPMS).
This paper presents a fast hysteretic switched-inductor charging regulator (SLCR) microsystem. It is powered by on-chip thermoelectric generators (TEGs) to supply Internet-of-Things (IoT) wireless microsensors. On-chip TEGs are appealing because they are 12–1400× smaller than off-chip ones. IoT sensors mostly idle in low-power mode and transmit data wirelessly only in high-power mode on demand. This requires CMOS SLCRs to respond quickly to abrupt load dumps caused by IoT sensors. State-of-the-art (SoA) SLCRs respond to load dumps in 100 μs–2.5 ms. This time duration amounts to a significant portion of the IoT sensor's data transmission time (500 μs–7 ms). This slow response time jeopardizes the quality of data transmission. This paper presents a fast hysteretic control that responds in 9.6 μs. This control adopts nested hysteretic architecture and requires only three comparators and simple combinational logics, which is appealing, considering the low power budget limited by on-chip TEGs. Moreover, this paper contributes detailed stability analysis, derives response time and accuracy and provides intuitive and accurate system design equations. Measured results of a 180-nm CMOS prototype validate that the proposed system shortens response time by 10–260× compared to the SoA.
Combined with the concept of intelligent tire, a tire condition monitoring system for predicting tire load information was designed, and a construction method of the tire load prediction model was proposed. Based on the finite element method, the construction process of tire load prediction model was explored. Under different inflation pressure and radial force, the tire deflection, the variation of tread height and tire cavity height in the grounding center area were obtained. Based on the above data, the tire radial stiffness fitting model and tread height variation fitting model were established. Finally, according to the theoretical formula of tire radial stiffness, the tire load prediction model was established and its validity was verified. The results show that the prediction model has high accuracy and can meet the requirements of use, which provides a theoretical basis for the development and design of tire condition monitoring system.
The challenges of developing a micro electromagnetic power generator are to increase the flux density from the thin permanent magnet and reduce the resistance of the micro high-winding-density coil. To overcome these challenges, we propose a novel MEMS power generator for low-frequency-vibration energy harvesting employing a 16-poles thin magnet plate and a high-aspect-ratio spiral micro array coil. Transient magnetic analysis has proved that the multi-pole magnet thin plate (8.9 × 8.9 × t0.5 mm) magnetized by laser assisted heating helps increase the output power from the generator compared with the unidirectional one. The high-aspect-ratio spiral micro array coil (width: 80 µm, thickness: 160 µm, total turns: 144) fabricated by the combination of multilayer SU-8 micro moldings, copper plating, and silver paste screen printing is beneficial for increasing coil density and reducing resistance, thus improving output power. The vibration experiment showed that in terms of no consideration of spring and guideway structure, when the magnet is directly vibrated by an actuator, the induced voltage, generated power, and power density were 1.63 mV, 0.12 µW and 1.03 µW/cm3, respectively at an excitation frequency of 10 Hz with an amplitude of 2 mm. When a 3D-printed cantilever beam was adopted as the spring and guideway structure for the resonant prototype, the counterparts were 8.48 mV, 3.34 µW and 5.22 µW/cm3, respectively at 38 Hz and 2 mm excitation (corresponding to a vibration acceleration peak of 11.6 g).
This research proposed intermediate materials between Cu filler and Si wafer to reduce the coefficient of thermal expansion (CTE) mismatch in the through silicon via (TSV) structure. The proposed material is Ni underlayer because it has CTE value between Cu and SiO2 which is 13 ppm/°C (Cu = 17 ppm/°C, SiO2 = 0.6 ppm/°C). The deposition process of nickel underlayer was conducted using electroless deposition process at various pH value (4.5, 5.5 and 6.5) of plating bath and deposition time (20, 40 and 60 minutes). The deposition behaviour was studied through surface and cross-sectional analysis under scanning electron microscopy (SEM). The Ni thickness was measured using cross-sectional analysis under SEM. The chemical composition of Ni deposits was measured using energy dispersive spectroscopy equipped on SEM. The performance test analysis was conducted using Standard ASTM D3359 (Cross Hatch Tape-Test) for coating adhesion test and 4-Point Probe Test for resistivity measurement. It was found that the optimum pH of the Ni bath is 6.5 due to high stability of plating bath to form uniform Ni deposited on silicon wafer. These optimum coating parameters showed homogeneous and uniform distribution of Nickel deposited on the surface of silicon with excellent adhesion properties for all pH value.
A 50 kbps/ISM band (902 − 926 MHz) low power transceiver for short-range wireless sensor networks (WSN) has been designed in 0.18 μm 1-poly-6 metal CMOS technology and occupy 950 μm × 800 μm. The proposed WSN transceiver designed based on an improved version of the Amplitude-Shift Keying communication scheme has a better continuous RF modulated carrier waveform as well as does not require complex modulator/demodulator circuits. In addition, to reduce power dissipation and increase power efficiency many circuit techniques have been adopted. The power dissipation and the power efficiency of the proposed WSN transceivers are 1.58 mW and 21%, respectively.
This paper presents a sensor front end for air pressure sensor, relative humidity (RH) sensor, and accelerometer in a standard CMOS process, equipped with a wide input range high-resolution capacitance-to-digital converter (CDC). For air pressure and RH, interdigitated top metals in air and polyimide are exploited, respectively, which exhibit the change in dielectric constant. For acceleration, separation among three bondwires is exploited. These sensing transducers induce capacitance change that is quantized by a CDC based on a dual-quantization architecture that employs a single-bit first-order ΔΣ modulator and a 7-bit SAR analog-to-digital converter (ADC). Implemented in 0.18-μm CMOS, the air pressure sensor, RH sensor, and accelerometer achieve a noise floor of 0.14 psi/√rmHz, 0.001 %RH/√rmHz, and 4.6 mg/√rmHz, respectively. The CDC achieves a resolution of 864 aF (minimum resolution of 116 aF) when the sensing capacitance is 10 pF and consumes 3 μW from 1.1-V supply.
Everything must be connected, monitored, and networked: this is the core tenet of the Internet of Things (IoT). This popular idea is most commonly achieved through the use of wireless systems, a term that could reference any of the following: active or passive RF identification (RFID) tags, wireless medical implant devices, wireless sensor networks, and other low-power IoT solutions. The plethora of terms used is due to the large application space and rapid pace of development in this field. We will mainly use the term RFID when describing these wireless systems.
This paper presents the development of wireless condition monitoring system for rotating machinery powered by a hybrid vibration based energy harvester. The self-powered condition monitoring system consists of three parts. The first part of the system is the energy harvester, the second part is the power management and the third part is the android based user interface. The system used a hybrid energy harvester (piezoelectric and electromagnetic) to harvest energy from the vibrating machine at a resonance frequency of 50±2 Hz and 0.25g ms-2 of acceleration. The maximum output power from the hybrid harvester was 3.00 mW at 200 kΩ of load resistor. The power management circuit efficiency was 85% with output power of 2.55 mW. An accelerometer sensor and a temperature sensor were connected to the power management unit to sense the vibration and temperature level of the machine. Data from the sensors were transmitted through the wireless Bluetooth dongle to the android phone for end user monitoring. An android application was developed to receive the acceleration and temperature condition monitoring. At maximum power, initial charging duration of the supercapacitor was 130 seconds, and duration for recharging to 8.2V was 15 seconds. Therefore, the self-powered system managed to transmit data to the android application 15 second's intervals.
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Although microsystems can nowadays consume microwatts, onboard batteries can be so small and leaky that sustaining microwatts for months or years without recharge cycles can be virtually impossible. Tiny photovoltaic cells and thermoelectric generators can help, but only when light or heat is available, and only to the extent that light intensity and thermal gradients allow. This is why energy-harvesting microsystems idle and shut down often and fast-wakeup provisions are important. The 0.18-μm CMOS charger proposed here is 8.31% more efficient during wakeup than the smallest reported and 7.69% more efficient than the next best, but without a 1:60 off-chip transformer and without vibration energy. Although 3.27% less efficient than the most efficient, the system here uses three fewer off-chip inductors. And after waking, the system is 5% to 46% more efficient than the others. The key innovations are low-power management and design. The system in essence charges a 200-pF capacitor with just enough energy to transfer two energy packets per cycle: one to charge a 1.8-μF battery and the other to replenish the 200 pF. This way, and with 100 nF across the source, the system charges a fully depleted 1.8-μF battery to 0.9 V in 45 ms and draws in steady state 98.8%-99.7% of available input power to deliver 76%-86% of the 40-150 μW drawn. IEEE
This paper presents a fully integrated system-on-chip wireless transmitter that has no need for an external quartz crystal frequency reference. Instead, a nontrimmable $LC$ oscillator (LCO) is implemented, operating at a fixed frequency of roughly 3.2 GHz. This LCO serves as the accurate frequency reference of the transmitter and is used to derive a frequency in the sub-GHz range for wireless applications via a fractional phase-locked loop. The digital functionality required for the frequency generation and thus for the wireless operation is performed by an 8-b microcontroller. The calibration data as well as the application specific firmware are stored in an integrated EEPROM. An initial frequency accuracy of $±$52 ppm over a temperature of -20 °C to 85 °C is achieved using only two temperature insertions for the calibration. The device covers a continuous frequency range of 10-960 MHz and provides an ASK and GFSK operation. A low harmonic power amplifier was implemented to overcome design issues due to injection modulation effects. The chip is implemented in a 130 nm standard CMOS process and constitutes a new approach for a fully integrated wireless sub-GHz transmitter that is competitive to state-of-the-art quartz crystal-based transmitters as well as to already existing crystal-less architectures.
In this paper, a novel pressure-sensing technique based on measuring the relative permittivity of air is introduced. Previous works in this area are mostly centered around mechanical sensors paired with electrical read-out circuits. However, the proposed CMOS-based pressure sensor is able to achieve the full sensing process electrically, from the sensing itself to the readout, with no need for post-processing or mechanical parts. In order to sense the pressure-dependent permittivity, a comb-structured top metal layer in a standard-CMOS process is proposed. The layer’s capacitance is read with a capacitance-to-voltage converter using a differential RC circuit. The proposed readout circuit addresses issues such as 1/f noise for a more accurate output. A prototype chip was realized with a 0.25- $\mu$ m standard-CMOS process, and consumed 1.3 mW using a 2.5-V supply. The chip testing results showed a correlation between pressure and output voltage of 6 mV per atm of pressure change, confirming the functionality of this technique.
Film bulk acoustic wave resonator (FBAR) experienced skyrocketing development in the past 15 years, owing to the explosive development of mobile communication. It stands out in acoustic filters mainly because of high quality factor, which enables low insertion loss and sharp roll off. Except for the massive application in wireless communication, FBARs are also promising sensors because of the high sensitivity and readily integration ability to miniaturize circuits. On the ground of summarizing FBAR's application in wireless communication as filters and in sensors including electronic nose, bio field, and pressure sensing, this paper review the main challenges of each application faced. The number of filters installed in the mobile phone has being grown explosively, which leads to overcrowded bands and put harsh requirements on component size and power consumption control for each unit. Data flow and rate are becoming increasingly demanding as well. This paper discusses three promising technical strategies addressing these issues. Among which coupled resonator filter is given intense attention because it is able to vigorously reduce the filter size by stacking two or more resonators together, and it is a great technique to increase data flow and rate. Temperature compensation methods are discussed considering their vital influence on frequency stability. Finally, materials improvement and novel materials exploration for band width modulation, tunable band acquisition, and quality factor improvement are discussed. The authors appeal attention of the academic society to bring AlN epitaxial thin film into the FBAR fabrication and have proposed a configuration to implement this idea.
Design of radios with ultra-low-power consumption can enable many new and exciting applications ranging from wearable healthcare to Internet of Things devices and beyond. Achieving low power operation is usually an exercise in trading-off important performance metrics with power. This chapter presents an overview of state-of-the-art narrowband architectures and techniques that achieve ultra-low-power operation, and concludes with a section that benchmarks recent state-of-the-art designs in order to illustrate power-performance trade-offs.
This chapter explores the use of high-Q RF resonators as both channel filtering and frequency generation elements in ultra-low energy wireless transceivers. Design tradeoffs in using resonators are discussed and an example receiver and transmitter system are presented. In the receiver, direct filtering at RF improves the frequency selectivity of the design and enables a low-energy ring-oscillator based frequency plan. In the transmitter, FBAR-based oscillators can eliminate the need for a PLL, reduce the power consumption of the frequency generation, and improve the overall transmitter efficiency at low output powers.
This paper presents a wide-frequencyrange, low-power transceiver with an automatic impedance-matching calibration for TV-white-space (TVWS) application. The wide-range automatic impedance matching calibration (AIMC) is proposed for the Drive Amplifier (DA) and LNA. The optimal S22 and S11 matching capacitances are selected in the DA and LNA, respectively. Also, the Single Pole Double Throw (SPDT) switch is integrated to share the antenna and matching network between the transmitter and receiver, thereby minimizing the systemic cost. An N-path filter is proposed to reject the large interferers in the TVWS frequency band. The current-driven mixer with a 25% duty LO generator is designed to achieve the high-gain and low-noise figures; also, the frequency synthesizer is designed to generate the wide-range LO signals, and it is used to implement the FSK modulation with a programmable loop bandwidth for multi-rate communication. The TVWS transceiver is implemented in 0.13 µm, 1-poly, 6-metal CMOS technology. The die area of the transceiver is 4 mm × 3 mm. The power consumption levels of the transmitter and receiver are 64.35 mW and 39.8 mW, respectively, when the output-power level of the transmitter is +10 dBm at a supply voltage of 3.3 V. The phase noise of the PLL output at Band 2 is -128.3 dBc/Hz with a 1 MHz offset. © 2016, Institute of Electronics Engineers of Korea. All rights reserved.
This chapter gives an overview of the requirements and status of tire pressure monitoring systems (TPMS) in view of MEMS sensors and the corresponding electronics. TPMS has become a nature market due to mandatory legal regulations for light vehicles in the USA. MEMS-based pressure sensors are used in the vast majority of so-called direct TPMS systems. After an introduction to the different processes of MEMS pressure sensors as well as the detection schemesthe power management of TPMS is discussed in detail. In addition, the use of energy harvesters as potential power sources for future TPMS systems, as well as the requirements and advantages of tire integrated TPMS systems, are discussed.
State-of-the-art tire pressure monitoring systems (TPMS) are wirelesssensor nodes mounted on the rim. Attaching the node on the inner liner of a tireallows sensing of important additional technical parameters, which may be used forimproved tracking and engine control, feedback to the power train and car-to-carcommunication purposes. Thus a significant step in car control appears feasible.Those new features come at a price: the maximum weight of the sensor is limited to5 g including package, power supply, and antenna. Robustness is required againstextreme levels of acceleration of up to 3,000 g (g = 9.81m/s2). The node size islimited to about 1 cm3 to avoid high force gradients due to device deformation andfinally, a 10-year power supply lifetime must be achieved. In this chapter we presenta self-sufficient tire-mounted wireless sensor node.
• with a bulk acoustic wave (BAW)-based low-power FSK transceiver;
• pioneered for an energy scavenger-based low-volume and low-weight powersupply; and
• a 3D vertical chip stack for best compactness, lowest volume, and highest robustnessfor pressure, inertia, and temperature sensing.
Some possible applications for MEMS technology development in structural health monitoring (SHM) are investigated in this chapter, particularly exploring the area of piezoelectric based sensors and fiber Bragg grating optical technologies. Although the latter is not included among typical MEMS, its functioning not being based upon electric sources, its small dimensions and low logistic impact make it a micro optical mechanical system (MOMS).
This work presents a single-chip sub-mm3 wireless pressure sensor suitable for tire pressure monitoring. The dynamic behavior and safety of an automobile tire is closely dependent on its inflation pressure: maintaining the manufacturer-recommended pressure is essential to prevent tire failure, provide stability, improve fuel efficiency and tire-life, and to reduce C02 emissions [1]. Thus, Tire-Pressure Monitoring Systems (TPMS) have become an essential component in modern vehicles, as stipulated by the National Highway Traffic Safety Administration (NHTSA) in 2006. State-of-the-art TPMS systems currently require a pressure sensor, multiple ICs, several external components, and a crystal on a PCB allowing wireless transmission of tire pressure [2] [3]. In this work, we describe a sub-mm3 fully integrated wireless pressure sensor including a pressure transducer, interface circuitry, integrated timing reference, and a wireless transmitter integrated into a single die.
This chapter looks at the circuit applications of intrinsically and extrinsically tuneable FBARs. VCOs seem to be one of the most attractive circuits for applications of the tuneable FBAR. They benefit both from high Q-factor (much higher than LC tanks based on semiconductor varactors) and tuneability. Perhaps tuneable and switchable filters are the most desired devices. The chapter includes several demonstrators of these types of filters. Some specific applications such as amplifiers, sensors and clocks are also considered.
The majority of microelectromechanical system (MEMS) devices must be combined with integrated circuits (ICs) for operation in larger electronic systems. While MEMS transducers sense or control physical, optical or chemical quantities, ICs typically provide functionalities related to the signals of these transducers, such as analog-to-digital conversion, amplification, filtering and information processing as well as communication between the MEMS transducer and the outside world. Thus, the vast majority of commercial MEMS products, such as accelerometers, gyroscopes and micro-mirror arrays, are integrated and packaged together with ICs. There are a variety of possible methods of integrating and packaging MEMS and IC components, and the technology of choice strongly depends on the device, the field of application and the commercial requirements. In this review paper, traditional as well as innovative and emerging approaches to MEMS and IC integration are reviewed. These include approaches based on the hybrid integration of multiple chips (multi-chip solutions) as well as system-on-chip solutions based on wafer-level monolithic integration and heterogeneous integration techniques. These are important technological building blocks for the ‘More-Than-Moore’ paradigm described in the International Technology Roadmap for Semiconductors. In this paper, the various approaches are categorized in a coherent manner, their merits are discussed, and suitable application areas and implementations are critically investigated. The implications of the different MEMS and IC integration approaches for packaging, testing and final system costs are reviewed.
This paper presents a 50/150/200 kbps, low power transceiver with one-point modulation and integrated single pole double throw (SPDT) switch for IEEE 802.15.4g application. To ensure that the proposed low power transceiver can operate at a multi data rate, multi data-rate (50/150/200 kbps) frequency shift keying (FSK) modulation is implemented using a phase-locked loop (PLL) with a programmable loop bandwidth. The bandwidth switching scheme is combined with the programmable loop bandwidth to support the high data rate in the PLL of the transmitter. In the receiver, the SPDT switch is integrated to share the antenna and matching network between the transmitter and receiver, thus minimizing the system cost. Also the active-RC band pass filter with the programmable bandwidth is designed to support the data rates of 50, 150, and 200 kbps. The capacitors in each data rate are shared efficiently to minimize the die area. The FSK transmitter is implemented using 0.18 μm 1-poly 6-metal complementary metal-oxide semiconductor technology. The die area of the transceiver is 4.0 mm2. The power consumption of the transmitter and receiver are 54 and 25 mW, respectively, when the output power level of the transmitter is +10.17 dBm at 1.8 V supply voltage. The phase noise of the PLL output at 1.8462 GHz is −118.13 dBc/Hz with a 1 MHz offset.
In today's hectic lifestyle, health has been seriously hampered due to sedentary work. This paper represents an idea of walking based wearable piezoelectric device that provides an alternate means for powering mobile phone batteries. Moreover, it simultaneously serves another purpose of providing an emergency torch. Since, the mechanism of the device is based on walking; the device promotes human metabolism as well as physical fitness. Hence, it can be seen as an e-health gadget that encourages walking exercise as a means to power emergency torch and mobile phone batteries. The portable device comprises of a piezoelectric power generator, connectors for charging different mobile phone batteries and a Light Emitting Diode (LED) embedded in shoe for providing emergency torch. Piezoelectric circuit harvests energy from user's trotter movement. This energy is amplified, rectified by using a DC convertor and then regulated to 4.2 volts which is required by a Li ion mobile battery. By using this device, a man weighing 60 Kg can charge a 800mAh capacity battery in 2.6 hours by normal walking.
This paper presents a self-sustaining integrated regulator for ultralow power two-input energy harvesting systems. The energy sources include photovoltaic panels and high frequency radio-frequency identification tags. An input-powered charge pump utilizing dynamic charge transfer switches with tunable voltages at the bottom of the pumping capacitors is proposed. No external pulse signal is required. An output-powered digitally controlled dc–dc switching converter with a low-complexity oversampling analog-to-digital converter is also proposed to analyze the error signal between the dc–dc switching converter output and the reference voltage. In order to avoid limit-cycle oscillation, a digital sigma-delta modulator is adopted to increase the equivalent resolution of the digital pulsewidth modulator. The system is completely implemented and fully integrated in a standard 0.18- (mu ) m CMOS process with a die area of 2.1 mm (^{2}) . The system output voltage is successfully regulated at 1 V and the measured maximum end-to-end conversion efficiency is (sim 57) %, when the loading current is 65 (mu ) A.
Phase-locked loops (PLL) are essential building blocks in wireless transceivers. Concerning data transmission and reception the performance of the PLL is crucial for the overall performance of the whole system. The transmitter architecture of the presented system does not use mixers but the PLL itself for FSK modulation. Therefore especially the bandwidth of the PLL influences performance parameters. As the PLL bandwidth is subject to significant variations due to process, temperature and supply voltage, bandwidth calibration is an important measure to ensure the PLL performance specifications. This paper presents two methods which use building blocks of an existing transceiver to calibrate the PLL bandwidth. Both methods use existing features of the transceiver architecture and therefore require only minimal adjustments and in principal no additional building blocks in order to accomplish bandwidth calibration. The first method uses an ADC to measure the PLL Loop Filter Voltage and the second employs the receiver to observe the frequency and phase of the PLL output signal. The proposed methods have been verified by measurements using a test chip implemented in a low-cost Infineon 130 nm CMOS process and an FPGA board. The variation of the PLL bandwidth after calibration is lower than ±10% compared to more than ±60% for an uncalibrated PLL. The time needed for calibration lies between 32 μs and 200 μs.
Wireless sensor networks (WSN) have a great prospect in many applications, among which the monitoring of hazardous environments is becoming more and more important. The basic requirements of WSN design are low cost and low power consumption, and then a low-power system-on-chip implementation is an optimal solution for WSN nodes. However, the radio-frequency (RF) part of a node chip is usually power hungry and difficult to fully integrate, so many previous works have focused on the design of RF transceivers for WSN. Specifically, for hazardous applications, the communication range is required to be long enough to protect human from harmful environments. So a long effective communication distance is also necessary for WSN transceivers in hazardous applications. In this paper, we give a survey and a classification of WSN transceivers. Furthermore, we analyze the advantages and disadvantages of three main WSN transceivers, i.e. on-off keying transceivers, ultra-wide band transceivers, and frequency shift keying transceivers; and then find out the one most suitable for hazardous applications.
This paper presents a wireless transceiver for WSNs using insects. It employs current reuse, switch-less switching, and fast PLL on/off switching techniques to reduce the power, size, cost, and weight of the sensor node. Implemented in 130-nm CMOS technology, the transceiver merges VCO, PA, LNA, TX/RX switch, and modulator into a common branch to reduce its power and complexity. In TX mode, the transmit-power can be tuned from -30dBm to -4.4dBm. The sensitivity measured for 0.1% BER in RX mode is -90dBm.
A wireless sensor network for condition monitoring and its corresponding sensor node powered by a vibration energy harvester producing about 100 μW are presented. The sensor network utilizes an asynchronous beacon-detection based duty cycle control architecture to reduce power consumption and support ID-based TDMA while avoiding the need for timing synchronization between nodes. It also provides FDMA and fixed-time slot TDMA for further network flexibility. The sensor node transceiver includes a duty-cycle timing control unit to minimize power consumption; an LO-less, TDMA-capable, addressable beacon receiver; an FDMA-capable transmitter; and a low-power, universal sensor interface. The proposed sensor node, implemented in 0.13- μm CMOS technology, achieves low power consumption and a high degree of flexibility without requiring calibration or the use of BAW or SAW filters. The sensor node is experimentally demonstrated to operate autonomously from the power provided by a piezoelectric vibration energy harvester with dimensions of 27 × 23 × 6.5 mm3 excited by 4.5-m/s2 acceleration at 40.8 Hz. The WSN condition monitoring behavior is measured with a capacitive temperature sensor, and achieves an effective temperature resolution of 0.36 °C.
So far the worlds of building automation and power networks have co-existed electrically attached but without data interaction, with different, and sometimes divergent, goals and requirements. The smartgrid community is coping nowadays with a new phase in the deployment of its vision: the integration of smart buildings, making use of their services and advantages to enable more complex functionalities at a global level. The main objective of this paper is to review latest results of the research community of industrial electronics, whose society within the IEEE, the IES, acts as the organizer of this conference. At the conference, latest advances and developments in design, modelling, simulating and implementing tools for, or systems of, sensor and/or actuator networks with advances towards user orientation, wireless connectivity, dependability, energy efficiency, context awareness and ubiquitous computing will be presented.
The potential application space for miniaturized systems like wireless microsensors is expansive, from reconnaissance mission work and remote sensors to biomedical implants and disposable consumer products. Conforming to microscale dimensions, however, constrains energy and power to such an extent that sustaining critical power-hungry functions like wireless communication is problematical. Harvesting ambient kinetic energy offers an appealing alternative, except the act of transferring energy requires power that could easily exceed what the harvester generates in the first place. This paper reviews piezoelectric and electrostatic harvester circuits, describes how to design low-power switched-inductor converters capable of producing net energy gains when supplied from piezoelectric and electrostatic transducers, and presents experimental results from prototype embodiments. In the electrostatic case shown, the controller dissipated 0.91 nJ per cycle and the switched-inductor precharger achieved 90.3% efficiency to allow the harvester to net a gain of 2.47 nJ per cycle from a capacitor that oscillated between 157 and 991 pF. The piezoelectric counterpart harnessed 1.6 to 29.6 μW from weak periodic vibrations with 0.05-0.16- m/s<sup>2</sup> accelerations and 65.3 μJ from (impact-produced) nonperiodic motion.
A fundamental problem that miniaturized systems, such as biomedical implants, face is limited space for storing energy, which translates to short operational life. Harvesting energy from the surrounding environment, which is virtually a boundless source at these scales, can overcome this restriction, if losses in the system are sufficiently low. To that end, the 2-μm bi-complementary metal-oxide semiconductor switched-inductor piezoelectric harvester prototype evaluated and presented in this paper eliminates the restrictions associated with a rectifier to produce and channel 30 μW from a periodic 72- μW piezoelectric source into a battery directly. In doing so, the circuit also increases the system's electrical damping force to draw more power and energy from the transducer, effectively increasing its mechanical-electrical efficiency by up to 78%. The system also harnesses up to 659 nJ from nonperiodic mechanical vibrations, which are more prevalent in the environment, with 6.1±1.5% to 8.8±6.9% of end-to-end mechanical-electrical efficiency.
Wireless communication in a car has several advan- tages, given that demanded safety and real-time requirements are fulfilled. This paper presents a wireless MAC protocol designed for the needs of automotive and industrial applications. The proposed MAC protocol provides special support for network traffic prioritization in order to guarantee worst-case message delays for a set of high-prioritized nodes. The performance is further analyzed with a network simulator and compared with the IEEE 802.15.4 standard CSMA/CA protocol. I. INTRODUCTION A modern car integrates hundreds of electronic sensors and actuators, which are connected via cables with an overall length of up to 4 km. Two major drawbacks of these wired systems are a) limited flexibility of deploying sensor devices because of the necessary cable routing, and b) increased weight and costs. For this reason, scientists are now looking for ways to replace some of these cables by wireless commu- nication, particularly for non-safety critical applications, such as the increasing number of passenger comfort sensors. In contrast to the research activities carried out during the past decade in the field of "Wireless Sensor Networks" (WSN), the underlying optimization targets, network topology and spatial sensor distribution for the considered automotive application field are quite different. Typical "Ad-Hoc" WSN applications (environmental and structural health monitoring, cp. (1)) share the common criteria that nodes are operated with low duty cycles and are optimized for low energy con- sumption, thereby trading-off message error rates, throughput and latency. However, these design targets fail to meet the requirements for wireless applications in the automotive field.
A complete wireless sensor node transceiver with 85.5 μW measured average power consumption is presented. The sensor node implements an asynchronous beacon-detection based duty cycle control architecture to reduce power consumption and avoid the need for timing synchronization between nodes, a common issue in sensor nodes. The transceiver includes a duty- cycle timing control block to minimize power consumption; an LO-less, TDMA-capable, addressable beacon receiver; an FDMA-capable transmitter; and a low-power, universal sensor interface. The proposed sensor node, implemented in 130 nm RF CMOS technology, achieves low power consumption and a high degree of flexibility without requiring calibration or the use of BAW or SAW filters. The sensor node is experimentally demonstrated to operate autonomously from the power provided by a piezoelectric vibration energy harvester with dimensions of 27 ൈ 23 ൈ 6.5 mm 3 excited by 4.5 m/s 2 acceleration at 40.8 Hz. I. INTRODUCTION
In recent years, bulk acoustic wave resonators (BAW) in combination with RF circuits have shown a big potential in achieving the low-power consumption and miniaturization level required to address wireless sensor nodes (WSN) applications. A lot of work has been focused on the receiver side, by integrating BAW resonators with low noise amplifiers (LNA) and in frequency synthesis with the design of BAW-based local oscillators, most of them working at fixed frequency due to their limited tuning range. At the architectural level, this has forced the implementation of several single channel transceivers. This thesis aims at exploring the use of BAW resonators in the transmitter, proposing an architecture capable of taking full advantage of them. The main objective is to develop a transmitter for WSN multi-channel applications able to cover the whole 2.4 GHz ISM band and enable the compatibility with wide-spread standards like Bluetooth and Bluetooth Low Energy. Typical transmissions should thus range from low data rates (typically tens of kb/s) to medium data rates (1 Mb/s), with FSK and GFSK modulation schemes, should be centered on any of the channels provided by these standards and cover a maximum transmission range of some tens of meters. To achieve these targets and circumvent the limited tuning range of the BAW oscillator, an up-conversion transmitter using wide IF is used. The typical spurs problems related to this transmitter architecture are addressed by using a combined suppression based on SSB mixing and selective amplification. The latter is achieved by cointegration of a high efficiency power amplifier with BAW resonators, which allows performing spurs filtering while preserving the efficiency. In particular the selective amplifier is designed by including in the PA analysis the BAW resonator parameters, which allows integrating the BAW filter into the passive network loading the amplifier, participating in the drain voltage shaping. Finally, the frequency synthesis section uses a fractional division plus LC PLL filtering and further integer division to generate the IF signals and exploit the very-low BAW oscillator phase noise. The transmitter has been integrated in a 0.18 µm standard digital CMOS technology. It allows addressing the whole 80 MHz wide 2.4 GHz ISM band. The unmodulated RF frequency carrier demonstrates a very-low phase noise of –136 dBc/Hz at 1 MHz offset. The IF spurs are maintained lower than –48 dBc, satisfying the international regulations for output power up to 10 dBm without the use of any quadrature error compensation in the transmitter. This is achieved thanks to the rejection provided by the SSB mixer and the selective amplifier, which can reach drain efficiency of up to 24% with integrated inductances, including the insertion losses of the BAW filter. The transmitter consumes 35.3 mA at the maximum power of 5.4 dBm under 1.6 V (1.2 V for the PA), while transmitting a 1 Mb/s GFSK signal and complying with both Bluetooth and Bluetooth Low Energy relative and absolute spectrum requirements.
The primary objective of this research was to investigate and develop an electrostatic energy-harvesting voltage-constrained CMOS/BiCMOS integrated circuit (IC) that harnesses ambient kinetic energy from vibrations with a vibration-sensitive variable capacitor and channels the extracted energy to charge an energy-storage device (e.g., battery). The proposed harvester charges and holds the voltage across the vibration-sensitive variable capacitor so that vibrations can induce it to generate current into the battery when capacitance decreases (as its plates separate). To that end, the research developed an energy-harvesting system that synchronizes to variable capacitor's state as it cycles between maximum and minimum capacitance by controlling each functional phase of the harvester and adjusting to different voltages of the on-board battery. One of the major challenges of the system was performing all of these duties without dissipating the energy harnessed and gained from the environment. Consequently, the system reduces losses by time-managing and biasing its circuits to operate only when needed and with just enough energy while charging the capacitor through an efficient inductor-based precharger. As result, the proposed energy harvester stores a net energy gain in the battery during each vibration cycle.
A low-power 2.4GHz heterodyne receiver front-end is integrated in 0.18mu;m CMOS using BAW solidly mounted resonators. The resonators with Qs of up to 580, provide both impedance matching and selectivity. An image rejection of up to 50dB, a NF of 11dB and IIP3 of -16.1dBm with a power dissipation of 1.8mW are demonstrated
3D integration is a key solution to the predicted performance problems of future ICs as well as it offers extreme miniaturization and cost-effective fabrication of More than Moore products (e.g. e-CUBES<sup>reg</sup>). Through silicon via (TSV) technologies enable high interconnect performance at relatively high fabrication cost compared to 3D packaging. A post backend-of-line TSV process is introduced as optimized technology for More than Moore products: The ICV-SLID process enables 3D integration of completely fabricated devices. Reliability issues, as thermo-mechanical stress caused by TSV formation and bonding are considered. The technology choice for the e-CUBES automotive application demonstrator is described.
We propose B-MAC , a carrier sense media access protocol for wireless sensor networks that provides a flexible interface to obtain ultra low power operation, effective collision avoidance, and high channel utilization. To achieve low power operation, B-MAC employs an adaptive preamble sampling scheme to reduce duty cycle and minimize idle listening. B-MAC supports on-the-fly reconfiguration and provides bidirectional interfaces for system services to optimize performance, whether it be for throughput, latency, or power conservation. We build an analytical model of a class of sensor network applications. We use the model to show the effect of changing B-MAC 's parameters and predict the behavior of sensor network applications. By comparing B-MAC to conventional 802.11-inspired protocols, specifically SMAC, we develop an experimental characterization of B-MAC over a wide range of network conditions. We show that B-MAC 's flexibility results in better packet delivery rates, throughput, latency, and energy consumption than S-MAC. By deploying a real world monitoring application with multihop networking, we validate our protocol design and model. Our results illustrate the need for flexible protocols to effectively realize energy efficient sensor network applications.
The first encompassing treatise of this new, but very important field puts the known physical limitations for classic 2D electronics into perspective with the requirements for further electronics developments and market necessities. This two-volume handbook presents 3D solutions to the feature density problem, addressing all important issues, such as wafer processing, die bonding, packaging technology, and thermal aspects. It begins with an introductory part, which defines necessary goals, existing issues and relates 3D integration to the semiconductor roadmap of the industry. Before going on to cover processing technology and 3D structure fabrication strategies in detail. This is followed by fields of application and a look at the future of 3D integration. The contributions come from key players in the field, from both academia and industry, including such companies as Lincoln Labs, Fraunhofer, RPI, ASET, IMEC, CEA-LETI, IBM, and Renesas.
IntroductionKey Requirements for 3D-Interconnect Technologies3D Technologies at IMECReferences
This document is part of Subvolume A5: 'Structure Types. Part 5: Space Groups (173) P63 - (166) R-3m' of Volume 43 'Crystal Structures of Inorganic Compounds' of Landolt-Börnstein - Group III 'Condensed Matter'.
IntroductionCommercial PrecursorsDeposition Process FlowComplete TSV Metallization Including Filling and Etchback/CMPConclusions
References
This paper presents a 2.45 GHz low noise amplifier (LNA), built in a 0.13 mum CMOS process. It has an on-chip matching network and contains integrated bulk acoustic wave (BAW) resonators for narrow-band filtering at RF. The voltage gain of LNA and matching network is 31.5 dB with 4.7 dB noise figure (NF) at a current consumption of 2 mA.
3D integration of micro electromechanical systems (MEMS) is expected to reduce the foot print of existing MEMS products and enable production of miniaturized sensor nodes on a large scale. However, 3D integration of MEMS is in general different from 3D integration of planar integrated circuits (ICs) due to additional mechanical requirements. Specifications regarding properties like stiffness, volume, and mass must be taken into consideration when selecting stacking technologies for MEMS. A demonstrator with a 3D integrated MEMS and the ideas behind the selection of stacking technologies are presented in this paper.
Fraunhofer IZM introduced a 3-D integration process, the so-called ICV-SLID technology based on inter-chip vias through the device substrates (through silicon vias) and metal bonding using solid-liquid-interdiffusion (SLID) soldering for simultaneous mechanical and the electrical connection [1]. The ICV-SLID technology is optimized for 3D integration of e-CUBES processing units, while interconnection techniques by hollow vias and Au stud bumps are used for stacking of sensor devices to the 3D-IC.
In this paper, a solution to realize local oscillators (LO) for a low power super-heterodyne receiver is presented. The first oscillator uses a bulk acoustic wave (BAW) resonator with high Q-factor. A quasi- harmonic quadrature relaxation oscillator with large tuning range is used to compensate for variations in the first oscillator and to cover the entire bandwidth for multiple channel selection.
This paper explores the design and implementation of a low-power two-channel transceiver using micromachined resonators. Wireless sensor networks require transceivers that are small, cheap, and power efficient. RF-MEMS resonators are utilized to accommodate these constraints. The prototype 1.9GHz transceiver, designed in 0.13 μm CMOS, operates at 1.2V and consumes 3mA in receive mode and transmits 1.6dBm with 17% efficiency. The two 40kb/s channels achieve a sensitivity of -78dBm with a 10 μs receiver start-up time.
The fundamentals of bulk-acoustic-wave (BAW) devices and the performance of state-of-the-art film bulk-acoustic-resonator (FBAR) filters is reviewed. The key role that high performance RF-filters play in handset applications is discussed and the benefit of silicon technologies outlined. Key processes in manufacturing of FBARs are briefly reviewed. The appealing simplicity of filter modeling and design is presented. Monolithic integration of "system-on-chip" together with RF-ICs is technically feasible and has been demonstrated. Conditions under which this will commercially make sense as compared to hybrid integration "system-in-package" is discussed. Examples of state-of-the-art in BAW filters in production and ramp-up status are presented.
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