Publications

119 Results
Skip to search filters

Inductive coupling for increased bandwidth of aluminum nitride contour-mode microresonator filters

IEEE MTT-S International Microwave Symposium Digest

Nordquist, Christopher N.; Henry, M.D.; Nguyen, Janet H.; Clews, Peggy; Lepkowski, Stefan M.; Grine, Alejandro J.; Dyck, Christopher D.; Olsson, Roy H.

Inductive coupling and matching networks are used to increase the bandwidth of filters realized with aluminum nitride contour-mode resonators. Filter bandwidth has been doubled using a wirebonded combination of a wafer-level-packaged resonator chip and a high-Q integrated inductor chip. The three-pole filters have a center frequency near 500 MHz, an area of 9 mm × 9 mm, insertion loss of < 5 dB for a bandwidth of 0.4%, and a resonator unloaded Q of 1600.

More Details

A Fully Integrated Oven Controlled Microelectromechanical Oscillator - Part II: Characterization and Measurement

Journal of Microelectromechanical Systems

Wojciechowski, Kenneth W.; Olsson, Roy H.

This paper, the second of two parts, reports the measurement and characterization of a fully integrated oven controlled microelectromechanical oscillator (OCMO). The OCMO takes advantage of high thermal isolation and monolithic integration of both aluminum nitride (AlN) micromechanical resonators and electronic circuitry to thermally stabilize or ovenize all the components that comprise an oscillator. Operation at microscale sizes allows implementation of high thermal resistance platform supports that enable thermal stabilization at very low-power levels when compared with the state-of-the-art oven controlled crystal oscillators. A prototype OCMO has been demonstrated with a measured temperature stability of -1.2 ppb/°C, over the commercial temperature range while using tens of milliwatts of supply power and with a volume of 2.3 mm3 (not including the printed circuit board-based thermal control loop). In addition, due to its small thermal time constant, the thermal compensation loop can maintain stability during fast thermal transients (>10 °C/min). This new technology has resulted in a new paradigm in terms of power, size, and warm up time for high thermal stability oscillators. [2015-0036].

More Details

A Fully Integrated Oven Controlled Microelectromechanical Oscillator - Part I: Design and Fabrication

Journal of Microelectromechanical Systems

Wojciechowski, Kenneth W.; Baker, Michael S.; Clews, Peggy J.; Olsson, Roy H.

This paper, the first of two parts, reports the design and fabrication of a fully integrated oven controlled microelectromechanical oscillator (OCMO). This paper begins by describing the limits on oscillator frequency stability imposed by the thermal drift and electronic properties (Q, resistance) of both the resonant tank circuit and feedback electronics required to form an electronic oscillator. An OCMO is presented that takes advantage of high thermal isolation and monolithic integration of both micromechanical resonators and electronic circuitry to thermally stabilize or ovenize all the components that comprise an oscillator. This was achieved by developing a processing technique where both silicon-on-insulator complementary metal-oxide-semiconductor (CMOS) circuitry and piezoelectric aluminum nitride, AlN, micromechanical resonators are placed on a suspended platform within a standard CMOS integrated circuit. Operation at microscale sizes achieves high thermal resistances (∼10 °C/mW), and hence thermal stabilization of the oscillators at very low-power levels when compared with the state-of-the-art ovenized crystal oscillators, OCXO. A constant resistance feedback circuit is presented that incorporates on platform resistive heaters and temperature sensors to both measure and stabilize the platform temperature. The limits on temperature stability of the OCMO platform and oscillator frequency imposed by the gain of the constant resistance feedback loop, placement of the heater and temperature sensing resistors, as well as platform radiative and convective heat losses are investigated. [2015-0035].

More Details

Radio Frequency Microelectromechanical Systems [Book Chapter Manuscript]

Nordquist, Christopher N.; Olsson, Roy H.

Radio frequency microelectromechanical system (RF MEMS) devices are microscale devices that achieve superior performance relative to other technologies by taking advantage of the accuracy, precision, materials, and miniaturization available through microfabrication. To do this, these devices use their mechanical and electrical properties to perform a specific RF electrical function such as switching, transmission, or filtering. RF MEMS has been a popular area of research since the early 1990s, and within the last several years, the technology has matured sufficiently for commercialization and use in commercial market systems.

More Details

Suppressing Fine-frequency modes in Aluminum Nitride microresonators

IEEE International Ultrasonics Symposium, IUS

Branch, Darren W.; Olsson, Roy H.

Eliminating spurious modes in Aluminum Nitride (AlN) microresonators improves their insertion loss and quality factor by reducing acoustic energy leakage. Spurious modes that result from transverse wave propagation, termed fine-frequency modes, leak energy and propagate in the electrical busing and appear near the fundamental resonance. Although these modes can be predicted using three-dimensional (3D) finite element methods (FEM) for devices with very short acoustic length (e.g. 1 acoustic wavelength), 3D FEM is very slow and memory intensive when compared to a two-dimensional (2D) simulation. A fast 2D coupling-of-modes (COM) model was developed to predict, identify and implement strategies to suppress the fine-frequency modes.

More Details

Fully integrated switchable filter banks

IEEE MTT-S International Microwave Symposium Digest

Crespin, Emily R.; Olsson, Roy H.; Wojciechowski, Kenneth W.; Branch, Darren W.; Clews, Peggy J.; Hurley, Richard B.; Gutierrez, J.

Fully integrated switchable filter have been successfully demonstrated using a ra CMOS SOI process in conjunction with an a (AlN) microresonator process. Single pole-mul were developed in the CMOS SOI process th multi-project wafer runs while the filters were aluminum nitride based microresonators. Each concurrent design cycles and was demonstrated to integration. After design improvements to bo full monolithic integration was implem microresonator filters with the CMOS switc compatibility of the two technologies. A four ch switchable bank of 7MHz bandwidth filters demonstrated exhibiting approximately 8 dB of 60dB of stop band rejection. © 2012 IEEE.

More Details

Chip scale mechanical spectrum analyzers based on high quality factor overmoded bulk acouslic wave resonators

Olsson, Roy H.

The goal of this project was to develop high frequency quality factor (fQ) product acoustic resonators matched to a standard RF impedance of 50 {Omega} using overmoded bulk acoustic wave (BAW) resonators. These resonators are intended to serve as filters in a chip scale mechanical RF spectrum analyzer. Under this program different BAW resonator designs and materials were studied theoretically and experimentally. The effort resulted in a 3 GHz, 50 {Omega}, sapphire overmoded BAW with a fQ product of 8 x 10{sup 13}, among the highest values ever reported for an acoustic resonator.

More Details

Phonon manipulation with phononic crystals

Olsson, Roy H.; Kim, Bongsang K.; Reinke, Charles M.

In this work, we demonstrated engineered modification of propagation of thermal phonons, i.e. at THz frequencies, using phononic crystals. This work combined theoretical work at Sandia National Laboratories, the University of New Mexico, the University of Colorado Boulder, and Carnegie Mellon University; the MESA fabrication facilities at Sandia; and the microfabrication facilities at UNM to produce world-leading control of phonon propagation in silicon at frequencies up to 3 THz. These efforts culminated in a dramatic reduction in the thermal conductivity of silicon using phononic crystals by a factor of almost 30 as compared with the bulk value, and about 6 as compared with an unpatterned slab of the same thickness. This work represents a revolutionary advance in the engineering of thermoelectric materials for optimal, high-ZT performance. We have demonstrated the significant reduction of the thermal conductivity of silicon using phononic crystal structuring using MEMS-compatible fabrication techniques and in a planar platform that is amenable to integration with typical microelectronic systems. The measured reduction in thermal conductivity as compared to bulk silicon was about a factor of 20 in the cross-plane direction [26], and a factor of 6 in the in-plane direction. Since the electrical conductivity was only reduced by a corresponding factor of about 3 due to the removal of conductive material (i.e., porosity), and the Seebeck coefficient should remain constant as an intrinsic material property, this corresponds to an effective enhancement in ZT by a factor of 2. Given the number of papers in literature devoted to only a small, incremental change in ZT, the ability to boost the ZT of a material by a factor of 2 simply by reducing thermal conductivity is groundbreaking. The results in this work were obtained using silicon, a material that has benefitted from enormous interest in the microelectronics industry and that has a fairly large thermoelectric power factor. In addition, the techniques and scientific understanding developed in the research can be applied to a wide range of materials, with the caveat that the thermal conductivity of such a material be dominated by phonon, rather than electron, transport. In particular, this includes several thermoelectric materials with attractive properties at elevated temperatures (i.e., greater than room temperature), such as silicon germanium and silicon carbide. It is reasonable that phononic crystal patterning could be used for high-temperature thermoelectric devices using such materials, with applications in energy scavenging via waste-heat recovery and thermoelectric cooling for high-performance microelectronic circuits. The only part of the ZT picture missing in this work was the experimental measurement of the Seebeck coefficient of our phononic crystal devices. While a first-order approximation indicates that the Seebeck coefficient should not change significantly from that of bulk silicon, we were not able to actually verify this assumption within the timeframe of the project. Additionally, with regards to future high-temperature applications of this technology, we plan to measure the thermal conductivity reduction factor of our phononic crystals as elevated temperatures to confirm that it does not diminish, given that the nominal thermal conductivity of most semiconductors, including silicon, decreases with temperature above room temperature. We hope to have the opportunity to address these concerns and further advance the state-of-the-art of thermoelectric materials in future projects.

More Details

Thermal conductivity manipulation in lithographically patterned single crystal silicon phononic crystal structures

IEEE International Ultrasonics Symposium, IUS

Kim, Bongsang; Nguyen, Janet; Reinke, Charles M.; Shaner, Eric A.; Harris, Charles T.; El-Kady, I.; Olsson, Roy H.

The thermal conductivity of single crystal silicon was engineered using lithographically formed phononic crystals. Specifically, sub-micron periodic through-holes were patterned in 500nm-thick silicon membranes to construct phononic crystals, and through phonon scattering enhancement, heat transfer was significantly reduced. The thermal conductivity of silicon phononic crystals was measured as low as 32.6W/mK, which is a ∼75% reduction compared to bulk silicon thermal conductivity [1]. This corresponds to a 37% reduction even after taking into account the contributions of the thin-film and volume reduction effects, while the electrical conductivity was reduced only by as much as the volume reduction effect. The demonstrated method uses conventional lithography-based technologies that are directly applicable to diverse micro/nano-scale devices, leading toward huge performance improvements where heat management is important. © 2011 IEEE.

More Details

Phonon considerations in the reduction of thermal conductivity in phononic crystals

Applied Physics A: Materials Science and Processing

Hopkins, Patrick E.; Phinney, Leslie M.; Rakich, Peter T.; Olsson, Roy H.; El-Kady, I.

Periodic porous structures offer unique material solutions to thermoelectric applications. With recent interest in phonon band gap engineering, these periodic structures can result in reduction of the phonon thermal conductivity due to coherent destruction of phonon modes characteristic in phononic crystals. In this paper, we numerically study phonon transport in periodic porous silicon phononic crystal structures. We develop a model for the thermal conductivity of phononic crystal that accounts for both coherent and incoherent phonon effects, and show that the phonon thermal conductivity is reduced to less than 4% of the bulk value for Si at room temperature. This has substantial impact on thermoelectric applications, where the efficiency of thermoelectric materials is inversely proportional to the thermal conductivity. © 2010 Springer-Verlag.

More Details

Manipulation of thermal phonons: A phononic crystal route to High-ZT thermoelectrics

Proceedings of SPIE - The International Society for Optical Engineering

El-Kady, I.; Su, Mehmet F.; Reinke, Charles M.; Hopkins, Patrick E.; Goettler, Drew; Leseman, Zayd C.; Shaner, Eric A.; Olsson, Roy H.

Phononic crystals (PnCs) are acoustic devices composed of a periodic arrangement of scattering centers embedded in a homogeneous background matrix with a lattice spacing on the order of the acoustic wavelength. When properly designed, a superposition of Bragg and Mie resonant scattering in the crystal results in the opening of a frequency gap over which there can be no propagation of elastic waves in the crystal, regardless of direction. In a fashion reminiscent of photonic lattices, PnC patterning results in a controllable redistribution of the phononic density of states. This property makes PnCs a particularly attractive platform for manipulating phonon propagation. In this communication, we discuss the profound physical implications this has on the creation of novel thermal phenomena, including the alteration of the heat capacity and thermal conductivity of materials, resulting in high-ZT materials and highly-efficient thermoelectric cooling and energy harvesting. © 2011 SPIE.

More Details

Silicon carbide lateral overtone bulk acoustic resonator with ultrahigh quality factor

Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)

Ziaei-Moayyed, M.; Habermehl, Scott D.; Branch, Darren W.; Clews, Peggy J.; Olsson, Roy H.

This work demonstrates a lateral overtone bulk acoustic resonator (LOBAR), which consists of an aluminum nitride (AlN) transducer coupled to a suspended thin silicon carbide (SiC) film fabricated using standard CMOS-compatible processes. The LOBAR design allows for high transduction efficiency and quality factors, by decoupling the transduction and energy storage schemes in the resonator. The frequency and bandwidth of the resonator were lithographically defined and controlled. A LOBAR operating at 2.93GHz with a Q greater than 100,000 in air was fabricated and characterized, having the highest reported f×Q product of any acoustic resonator to date.

More Details

Silicon carbide phononic crystal cavities for micromechanical resonators

Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)

Ziaei-Moayyed, M.; Su, M.F.; Reinke, Charles M.; El-Kady, I.; Olsson, Roy H.

This paper demonstrates silicon carbide phononic crystal cavities for RF and microwave micromechanical resonators. We demonstrate design, fabrication, and characterization of Silicon Carbide/air phononic crystals used as Bragg acoustic mirrors to confine energy in a lateral SiC cavity. Aluminum nitride transducers drive and sense SiC overtone cavities in the 2-3GHz range with fxQ products exceeding 3×1013 in air. This approach enables decoupling of the piezoelectric AlN material from the SiC cavity, resulting in high Q resonators at microwave frequencies. The SiC cavities are fabricated in a CMOS-compatible process, enabling integration with wirelesss communication systems.

More Details

Origins and mitigation of spurious modes in aluminum nitride microresonators

Olsson, Roy H.; Wojciechowski, Kenneth W.; Branch, Darren W.

Recently reported narrow bandwidth, <;2%, aluminum nitride microresonator filters in the 100-500 MHz range offer lower insertion loss, 100x smaller size, and elimination of large external matching networks, when compared to similar surface acoustic wave filters. While the initial results are promising, many microresonators exhibit spurious responses both close and far from the pass band which degrade the out of band rejection and prevent the synthesis of useful filters. This paper identifies the origins of several unwanted modes in overtone width extensional aluminum nitride microresonators and presents techniques for mitigating the spurious responses.

More Details

NanoFIBrication of a two-dimensional phononic crystal in a free standing membrane

El-Kady, I.; Olsson, Roy H.

A two-dimensional phononic crystal (PnC) that can operate in the GHz range is created in a freestanding silicon substrate using NanoFIBrication (using a focused ion beam (FIB) to fabricate nanostructures). First, a simple cubic 6.75 x 6.75 ?m array of vias with 150 nm spacing is generated. After patterning the vias, they are backfilled with void-free tungsten scatterers. Each via has a diameter of 48 nm. Numerical calculations predict this 2D PnC will generate a band gap near 22 GHz. A protective layer of chromium on top of the thin (100 nm) silicon membrane confines the surface damage to the chromium, which can be removed at a later time. Inspection of the underside of the membrane shows the vias flaring out at the exit, which we are dubbing the 'trumpet effect'. The trumpet effect is explained by modeling the lateral damage in a freestanding membrane.

More Details

Multi-frequency aluminum nitride micro-filters for advanced RF communications

Olsson, Roy H.; Wojciechowski, Kenneth W.; Tuck, Melanie R.; Stevens, James E.; Nordquist, Christopher N.

An AlN MEMS resonator technology has been developed, enabling massively parallel filter arrays on a single chip. Low-loss filter banks covering the 10 MHz--10-GHz frequency range have been demonstrated, as has monolithic integration with inductors and CMOS circuitry. The high level of integration enables miniature multi-bandm spectrally aware, and cognitive radios.

More Details

Parallel lattice filters utilizing aluminum nitride contour mode resonators

Technical Digest - Solid-State Sensors, Actuators, and Microsystems Workshop

Wojciechowski, K.E.; Olsson, Roy H.

In this work we describe a new parallel lattice (PL) filter topology for electrically coupled AlN microresonator based filters. While 4th order, narrow percent bandwidth (0.03%) parallel filters based on high impedance (11 kΩ) resonators have been previously demonstrated at 20 MHz [1], in this work we realize low insertion loss PL filters at 400-500 MHz with termination impedances from 50 to 150 Ω and much wider percent bandwidths, up to 5.3%. Obtaining high percent bandwidth is a major challenge in microresonator based filters given the relatively low piezoelectric coupling coefficients, kt2, when compared to bulk (BAW) and surface (SAW) acoustic wave filter materials.

More Details

High speed (GHZ), ultra-high pressure (GPA) sensor array fabricated in integrated CMOS+MEMS process

Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS)

Okandan, Murat O.; Olsson, Roy H.; Baker, Michael; Resnick, Paul J.; Hill, Thomas A.; Lackey, Chad; Pearson, Sean P.; Castaneda, Jaime N.; Trott, Wayne T.; Jones, David A.

In order to observe and quantify pressure levels generated during testing of energetic materials, a sensor array with high temporal resolution (∼1 ns) and extremely high pressure range (> 1 GPa) is needed. We have developed such a sensor array which utilizes a novel integrated high performance CMOS+MEMS process. ©2009 IEEE.

More Details

Microresonant impedance transformers

Proceedings - IEEE Ultrasonics Symposium

Olsson, Roy H.; Wojciechowski, Kenneth W.; Tuck, Melanie R.; Stevens, James E.

Widely applied to RF filtering, AlN microresonators offer the ability to perform additional functions such as impedance matching and single-ended-to- differential conversion. This paper reports microresonators capable of transforming the characteristic impedance from input to output over a wide range while performing low loss filtering. Microresonant transformer theory of operation and equivalent circuit models are presented and compared with measured 2 and 3-Port devices. Impedance transformation ratios as large as 18:1 are realized with insertion losses less than 5.8 dB, limited by parasitic shunt capacitance. These impedance transformers occupy less than 0.052 mm2, orders of magnitude smaller than competing technologies in the VHF and UHF frequency bands. ©2009 IEEE.

More Details

Super high frequency width extensional aluminum nitride (AlN) MEMS resonators

Proceedings - IEEE Ultrasonics Symposium

Wojciechowski, Kenneth W.; Olsson, Roy H.; Nordquist, C.D.; Tuck, Melanie R.

Width extensional (WE) super high frequency (SHF) aluminum nitride (AlN) resonators have been fabricated using optical lithography. Solidly anchored WE resonators were shown to be superior to beam anchored resonators of the same size and it was verified that simply scaling resonator area does not improve insertion loss (IL). Resonators with an IL of -6.3 dB into 50 ohms at 4.1 GHz and -7.2 dB at 6.8 GHz have been demonstrated. This type of performance at 6.8 GHz is unprecedented for contour mode resonators and represents a 12.6 dB improvement over recently reported SHF AlN resonators. ©2009 IEEE.

More Details

SOI-Enabled MEMS Processes Lead to Novel Mechanical Optical and Atomic Physics Devices Presentation

Herrera, Gilbert V.; McCormick, Frederick B.; Nielson, Gregory N.; Nordquist, Christopher N.; Okandan, Murat O.; Olsson, Roy H.; Ortiz, Keith O.; Platzbecker, Mark R.; Resnick, Paul J.; Shul, Randy J.; Bauer, Todd B.; Sullivan, Charles T.; Watts, Michael W.; Blain, Matthew G.; Dodd, Paul E.; Dondero, Richard D.; Garcia, Ernest J.; Galambos, Paul; Hetherington, Dale L.; Hudgens, James J.

Abstract not provided.

SOI-Enabled MEMS Processes Lead to Novel Mechanical Optical and Atomic Physics Devices

Herrera, Gilbert V.; McCormick, Frederick B.; Nielson, Gregory N.; Nordquist, Christopher N.; Okandan, Murat O.; Olsson, Roy H.; Ortiz, Keith O.; Platzbecker, Mark R.; Resnick, Paul J.; Shul, Randy J.; Bauer, Todd B.; Sullivan, Charles T.; Watts, Michael W.; Blain, Matthew G.; Dodd, Paul E.; Dondero, Richard D.; Garcia, Ernest J.; Galambos, Paul; Hetherington, Dale L.; Hudgens, James J.

Abstract not provided.

Fundamental and overtone aluminum nitride dual mode resonator filters

Technical Digest - Solid-State Sensors, Actuators, and Microsystems Workshop

Olsson, Roy H.; Tuck, Melanie R.

This paper reports post-CMOS compatible aluminum nitride dual mode resonator filters that realize 4th order band-pass filters in a single resonator device. Dual mode filters at 106 MHz operating in their fundamental mode are reported with insertion losses as low as 5.5 dB when terminated with 150 Ω. A notching technique is demonstrated for varying the 3 dB bandwidth of these filters from 0.15 to 0.7%, overcoming a significant limitation of previous work. Dual mode filters operating at their 5th and 10th overtones are reported scaling the operating frequencies of this class of device to 0.55 and 1.1 GHz.

More Details

Post-cmos compatible aluminum nitride ring wave guide (RWG) resonators

Technical Digest - Solid-State Sensors, Actuators, and Microsystems Workshop

Wojciechowski, Kenneth W.; Olsson, Roy H.; Tuck, Melanie R.

This work presents a new type of MEMS resonator based on launching an acoustic wave around a ring. Its maximum frequency is set by electrode spacing and can therefore provide a means for developing resonators with center frequencies in the GHz. In addition since the center frequency is dependent on the average radius it is not subject to lithographic process variations in ring width. We have demonstrated several Ring Waveguide (RWG) Resonators with center frequencies at 484 MHz and 1 GHz. In addition we have demonstrated a 4th order filter based on a RWG design.

More Details

Integrated NEMS and optoelectronics for sensor applications

Czaplewski, David A.; Krishnamoorthy, Uma K.; Okandan, Murat O.; Olsson, Roy H.; Serkland, Darwin K.; Warren, M.E.

This work utilized advanced engineering in several fields to find solutions to the challenges presented by the integration of MEMS/NEMS with optoelectronics to realize a compact sensor system, comprised of a microfabricated sensor, VCSEL, and photodiode. By utilizing microfabrication techniques in the realization of the MEMS/NEMS component, the VCSEL and the photodiode, the system would be small in size and require less power than a macro-sized component. The work focused on two technologies, accelerometers and microphones, leveraged from other LDRD programs. The first technology was the nano-g accelerometer using a nanophotonic motion detection system (67023). This accelerometer had measured sensitivity of approximately 10 nano-g. The Integrated NEMS and optoelectronics LDRD supported the nano-g accelerometer LDRD by providing advanced designs for the accelerometers, packaging, and a detection scheme to encapsulate the accelerometer, furthering the testing capabilities beyond bench-top tests. A fully packaged and tested die was never realized, but significant packaging issues were addressed and many resolved. The second technology supported by this work was the ultrasensitive directional microphone arrays for military operations in urban terrain and future combat systems (93518). This application utilized a diffraction-based sensing technique with different optical component placement and a different detection scheme from the nano-g accelerometer. The Integrated NEMS LDRD supported the microphone array LDRD by providing custom designs, VCSELs, and measurement techniques to accelerometers that were fabricated from the same operational principles as the microphones, but contain proof masses for acceleration transduction. These devices were packaged at the end of the work.

More Details

A three-dimensional neural recording microsystem with implantable data compression circuitry

Digest of Technical Papers - IEEE International Solid-State Circuits Conference

Olsson, Roy H.; Wise, Kensall

A 256-site microsystem comprises 4 neural recording arrays with integrated amplification and multiplexing circuitry and an implantable spike detection ASIC. The spike detector compresses the amount of neural data by 92%, increasing the total number of channels recorded wirelessly from 25 to 312. The implantable circuitry consumes 5.4mW at 3V. ©2005 IEEE.

More Details

A digital accelerometer array utilizing suprathreshold stochastic resonance for detection of sub-Brownian noise floor accelerations

Carr, Dustin W.; Olsson, Roy H.

The goal of this LDRD project was to evaluate the possibilities of utilizing Stochastic resonance in micromechanical sensor systems as a means for increasing signal to noise for physical sensors. A careful study of this field reveals that in the case of a single sensing element, stochastic resonance offers no real advantage. We have, however, identified a system that can utilize very similar concepts to stochastic resonance in order to achieve an arrayed sensor system that could be superior to existing technologies in the field of inertial sensors, and could offer a very low power technique for achieving navigation grade inertial measurement units.

More Details
119 Results
119 Results