|PHASE III: The development of methods to produce structural protein fibers at industrially-relevant scales will support reproducible, commercially-viable, “green” manufacturing of the next generation of lightweight fibers for military and civilian needs. There are a number of military applications for a bio-derived alternative to nylon including ropes, webbing and harnesses, and advanced textiles for protection (e.g., the flame retardant-ACU), which are relevant to the civilian sector as well. Additional opportunities for dual-use commercialization include biomedical materials (micro-sutures, artificial ligaments and tendons), and biodegradable fishing nets and automotive air bags. Optimization of solution, spinning and post-spinning processing conditions, and thus enhancement of mechanical integrity, could lead to generation of bio-derived fibers that could replace synthetic fibers that are generated from harsh, chemical processes (e.g., Kevlar) for use in ballistic applications for the military and civilian first responders. Optimization could also open avenues toward use of bio-derived fibers in fiber-reinforced composites to replace the currently employed glass and natural fibers, which have disadvantages in terms of high energy demand for production and moisture absorptivity, respectively. Fiber-reinforced composites are widely used by the military in rigid shelter side panels, combat surgical hospitals and airbeams for deployable structures and military/civilian dual-use applications such as vehicle body panels and helicopter blades. Further applications are possible upon assessment of biodegradability, biocompatibility, and environmental stability.
1. Gentleman, E.; Lay, A.N; Dickerson, D.A.; Nauman, E.A.; Livesay, G.A.; Dee, K.C. (2003) Mechanical characterization of collagen fibers and scaffolds for tissue engineering. Biomaterials 24:3805-13.
2. Liu, W; Carlisle, C.R.; Sparks, E.A.; Guthold, M. (2010) The mechanical properties of single fibrin fibers. J. Thromb. Haemost. 8: 1030-36.
3. Rising, A.; Widhe, M.; Johansson, J.; Hedhammar, M. (2011) Spider silk proteins: recent advances in recombinant production, structure-function relationships and biomedical applications. Cell. Mol. Life. Sci. 68: 169-84.
4. Negishi, A.; Armstrong, C.L.: Kreplak, L.; Rheinstadter, M.C.; Lim, L-T.; Gillis, T.E.; Fudge, D.S. (2012) The productions of fibers and films from solubilized hagfish slime thread proteins. Biomacromolecules 13: 3475-82.
5. Lazaris, A.; Arcidiacono, S.; Huang, Y.; Zhou, J-F.; Duguay, F.; Chretien, N.; Welsh, E.A.; Soares, J.W.; Karatzas, C.N. (2002) Spider silk Fibers spun from soluble recombinant silk produced in mammalian cells. Science 295:472-6.
KEYWORDS: bio-derived fiber, biomaterials, structural proteins, recombinant, protein fiber
A14-016 TITLE: Ultra-low power "system-on-a-chip" integrated circuit for fieldable neurobiological
TECHNOLOGY AREAS: Electronics
OBJECTIVE: Develop an ultra-low voltage system for neurological sensing capable of operating with no secondary power supply, with performance in the range of current commercially available solutions. A successful application will include coordination with U.S. Army Research Laboratory (ARL) scientists to ensure understanding of the application space of sensing brain activity within real-world environments.
DESCRIPTION: Recent advances in neuroscience have made great strides towards improving our understanding of how the nervous system operates and our ability to monitor its function inaction. Meanwhile, drastic improvements in sensor technology, as well as streamlined system design, have led to more wearable electroencephalography (EEG) solutions, which hold the promise of performing true neurophysiologcal monitoring outside of the lab and in more everyday or even potentially hazardous environments. For example, use of dry (gel-free) electrodes greatly minimizes preparation time, and improved higher-bandwidth wireless technology has eliminated the need for a physical tether between a wearer and the system, while also reducing artifact noise.
Truly fieldable neurobiological sensing systems would be revolutionary for on-line monitoring of Soldier cognitive state in a wide range of environments, potentially integrated as part of a standard helmet or patrol cap. However, all current solutions for the electronics used within the central EEG data acquisition (DAQ) systems pose fieldability challenges because of size, weight, and power (SWAP) requirements. This is primarily due to the use of conventional integrated circuit (IC) design and components, which are based on standard operation levels of millivolts to volts and high power radios. As a result, they have an implicit requirement for conventional power supplies (e.g. batteries) that add substantial weight to the total package. Conventional systems have, at most, 8-12 hours of battery life; this adds the burden of requiring continual interaction and maintenance for the user. A system that is extremely small, lightweight, able to operate for extremely long periods (hundreds of hours to indefinitely), and requires virtually no interaction or direct attention from the user (a “construct-and-forget” approach) would reduce these barriers to fieldable systems integration and provide ground-breaking capabilities across a broad range of environments and application domains.
The intended goal of this proposal is to extend the operational time per use from hours to weeks, reduce the weight of the system to a few grams, and decrease the size of the system to a couple of square centimeters, through the development and refinement of a system-on-a-chip (SoC) DAQ system targeted for external electrophysiological neurological applications (e.g. EEG), which operates on ultra-low power requirements (microwatts). While some previous work has demonstrated putative systems operating on ultra-low power [1-5], none have been produced in a usable form-factor, or that operate within a power realm low enough to be completely self-sustaining (operating in milliwatt or hundreds of microwatt range) while containing the processing requirements necessary for EEG.
The Phase II goal will be to completely eliminate the necessity for an external power source through use of a local thermoelectric or other alternative source. In order to suit the largest range of envisioned applications, the final system would need to be capable of collecting high-resolution data such as from a dense array (e.g. 64+ channels), high data precision (24+ bit), or high sample rate (1 kHz) with resulting SNR comparable to that of conventional EEG measurement systems. Additionally, it must be capable of handling typical signal conditioning and pre-processing procedures for EEG, data storage, and near-field (<6 meter) transmission, with integrated power management as a central tenet. Local power may be appropriate, but must not require service/maintenance from the user, must be consistent with the goal of minimizing the size, weight, safety, and obtrusiveness of the total system, and must be compatible with long term human use applications.
PHASE I: Develop a System on a Chip design with multiple channel capability (three channel minimum) for application in a dry EEG data acquisition system. The SoC should include signal conditioning, preprocessing, storage, signal transmission, and integrated power management. The overall SoC should be capable of operating on ultra-low (< 100 microwatt) power supply. ARL can provide expertise in EEG application, potential use, and conventional system design as needed. Phase I deliverables include: 1) Deliver specifications and complete schematics for proposed SoC and components, 2) proof-of-principle simulation results (e.g., SPICE, CADENCE), providing evidence for operation equivalent to that of conventional-voltage EEG systems, and 3) a proposed power scavenging method that removes the need for an external power source or user maintenance, including plug-in charging or other interaction. The proposed SoC and power source should maintain an extremely small, lightweight form factor.
PHASE II: Fabricate, test and validate the performance of the design developed in Phase I, and develop a generation II design with expanded channel capability and operational performance equivalent to conventional methods as evidenced in both simulated (phantom) models and human users. Coordinate with U.S. Army Research Laboratory neurotechnology experts to enable the integration and testing of the developed technologies with a full EEG system form factor in a variety of relevant environments and use conditions, which can be performed by ARL. The generation II design should expand the SoC design to potentially include high-density (64+ channel) and/or high fidelity (24 bit, 1kHz) acquisition. This could be achieved in a single SoC or by multiplexing multiple SoC chips, but must maintain the goal of operation without external power source or user maintenance. By end of performance, deliver to ARL at least 10 functional SoC chip sets either already integrated or capable of integration with systems.
PHASE III: Develop a marketable device which could be used as the primary component of a fieldable EEG system, with potential uses in academic research, industry, medical, and military applications where high portability is crucial. Potential applications include monitoring of vigilance or mental fatigue, seizure prediction or identification, casualty or TBI assessment, or daily stress monitoring.
1. Calhoun, B.H.; Lach, J.; Stankovic, J.; Wentzloff, D.D.; Whitehouse, K.; Barth, A.T.; Brown, J.K.; Qiang Li; Seunghyun Oh; Roberts, N.E.; Yanqing Zhang, "Body Sensor Networks: A Holistic Approach From Silicon to Users," Proceedings of the IEEE , vol. 100, no. 1, pp. 91, 106, Jan. 2012
2. Kyungseok Kim; Agrawal, V.D., "True Minimum Energy Design Using Dual Below-Threshold Supply Voltages," VLSI Design (VLSI Design), 2011 24th International Conference on, pp. 292,297, 2-7 Jan. 2011
3. Otis, B.; Holleman, J.; Liao, Y. -T; Pandey, J.; Rai, S.; Su, Y.; Yeager, D., "Low power IC design for energy harvesting wireless biosensors," Radio and Wireless Symposium, 2009. RWS '09. IEEE, pp. 5,8, 18-22 Jan. 2009
4. Verma, N.; Shoeb, A.; Bohorquez, J.; Dawson, J.; Guttag, J.; Chandrakasan, A.P., "A Micro-Power EEG Acquisition SoC With Integrated Feature Extraction Processor for a Chronic Seizure Detection System," Solid-State Circuits, IEEE Journal of, vol. 45, no. 4, pp. 804,816, April 2010
5. Chen, G.; Fojtik, M.; Daeyeon Kim; Fick, D.; Junsun Park; Mingoo Seok; Mao-Ter Chen; Zhiyoong Foo; Sylvester, D.; Blaauw, D., "Millimeter-scale nearly perpetual sensor system with stacked battery and solar cells," Solid-State Circuits Conference Digest of Technical Papers (ISSCC), 2010 IEEE International, pp. 288,289, 7-11 Feb. 2010
6. U.S. Army Surgeon General. Army Medicine Strategy. US Army Medical Command, Fort Sam Houston, San Antonio, TX, USA, 2012
KEYWORDS: Electroencephalography, integrated circuit, microwatt, sub-threshold, ultra-low power, traumatic brain injury, cognitive monitoring
A14-017 TITLE: Flexible, high-frequency, high-durability, and multifunctional sensor film
TECHNOLOGY AREAS: Electronics
OBJECTIVE: To develop advanced flexible sensor system with distributed sensing capability for measuring extreme pressure/force/acceleration on Soldiers’ heads and bodies caused by ballistic, blast, and blunt impacts.
DESCRIPTION: Traumatic brain injuries (TBI’s) caused by extreme events such as blast, ballistic, and blunt impacts have produced a high incidence of casualties and long-term chronic consequences among U.S. troops fighting in Iraq and Afghanistan. In order to augment medical understanding of the injury and to develop drastically improved personal protection, there is an urgent need for sensors capable of measuring such extreme pressure on human bodies. The US Army has recently developed a single-point helmet sensor to collect data of hits from explosions and other blunt impacts , which, however, is unable to measure the pressure distribution on the entire head. To fully understand the pressure distribution on the entire head upon blast/ballistic/blunt impact, and to evaluate the effectiveness of protective helmet, measurement of multi-point 3D pressure distribution is needed.
Such advanced sensors are also needed for helmet and body armor testing. The current testing standards measure the maximum deformation of clay behind a helmet or a body armor plate during ballistic impact tests and uses this back face signature as a predictor of behind armor blunt trauma injury [2-4]. However, the clay deformation and blunt trauma injury have not been well correlated and understood. A direct measurement of multipoint dynamic pressure behind helmets and armor plates is extremely important to establish biomechanical-based behind-armor/helmet blunt trauma criteria for protective equipment.
The current commercial off-the-shelf sensors have not been able to meet the stringent demands posed by the high impact events. It is the objective of this SBIR program to develop an advanced flexible, high-frequency, high-durability and multifunctional lightweight film type sensor array system, which has (1) a capacity to measure extremely high pressure of 350 MPa (50 ksi) caused by multiple blasts, ballistic and blunt impacts, (2) an extremely fast time response (1 micro-second or less), (3) a large deformation capacity up to 5.08 cm (2 inches), (4) ability to record multi-point pressure profiles over a spatial resolution of 0.6 cm (0.25 inch) or less with a scalable total surface area of coverage up to 2 square meters, and (5) a wearable electronic system including data acquisition, storage, and power with a total volume no larger than 50 cubic centimeters with a fast sampling rate (at least 1MHz) to record the pressure history and the location of the blast/impact events. The system should able to function for at least 48 hours on a single charge. Equally important, the sensor must be soft, flexible, thin, lightweight, and friendly to human bodies.
PHASE I: The Phase I proposal should focus on pressure/force film sensors, including a detailed description of technical approaches to achieving the pressure/force, time response, and deformation requirements. The Phase I study shall develop a preliminary design of the proposed pressure/force film sensor array and a sensor calibration method. Ballistic and blunt impact tests shall be carried out to demonstrate the feasibility of the sensor to measure the behind-helmet/soft armor impact associated with a large deformation over a total area of at least 230 square centimeters (36 square inches). System design should demonstrate potential to meet performance metrics as enumerated in the topic description.
PHASE II: Using the results from Phase I, the Phase II effort shall develop a prototype wearable sensor array system having multi-point distributed pressure/force sensing capability and incorporated with MEMs accelerometers. The prototype shall have micro data acquisition, communication, and power modules. The prototype shall be integrated in the U.S. Army’s advanced combat helmets and soft armor and evaluated through ballistic, blast, and blunt impact tests. Required testing includes but is not limited to selected helmet and soft body armor systems. To facilitate sensor system development and integration into Army research initiatives, one (1) to four (4) developmental sensor systems should be supplied to the Army for conducting further testing during the Phase II process. System performance must be demonstrated to meet or exceed specific metrics as enumerated in the topic description.
PHASE III: In addition to military applications, the developed sensors can be applied to many other civilian applications such as crashworthiness in vehicle designs, blast resistance in commercial aircraft, weather and blast resistance in civil structures, sporting equipment, and law enforcement protective gear. Phase III should include establishment of a manufacturing infrastructure, either through an industrial partnership or development of in-house capabilities. The manufacturing capability should include sufficient volume and facilities to establish a fully commercialized sensor product and support a potential operational capability.
1. “New Sensor Systems to Measure Blast Impact,” Donna Miles, American Force Press Service, Jan 2008. (http://www.defense.gov/news/newsarticle.aspx?id=48590)
2. “Ballistic Resistance of Body Armor,” NIJ Standard-0101.06, National Institute of Justice, July 2008.
3. “Ballistic Test Method for Personal Armour Materials and Combat Clothing,” NATO Standardization Agreement (STANAG) 2920, Edition 2, North Atlantic Treaty Organization, 31 July 2003.
4. National Research Council, Testing of Body Armor Materials: Phase III, The National Academies Press, Washington, DC, ISBN: 978-0-309-25599-8, May 2012.
KEYWORDS: Traumatic brain injuries (TBI), wearable sensors, distributed pressure, extreme events, blast, ballistic, blunt, helmet body armor, ballistic testing
A14-018 TITLE: Low-profile antennas using anisotropic/inhomogeneous magneto-dielectric metamaterials
TECHNOLOGY AREAS: Electronics
The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 5.4.c.(8) of the solicitation.
OBJECTIVE: Develop low-profile Very-High Frequency/Ultra-High Frequency (VHF/UHF) antenna apertures using choice materials such as anisotropic/inhomogeneous magneto-dielectrics.
DESCRIPTION: The advent of metamaterials has extended the design space for antenna apertures [4, p.4, (2.20)] creating the possibility for very thin (relative to wavelength) antenna structures. While basic physics limits directivity [4, p.10, (2.107)] to the available aperture size, such restrictions do not preclude antennas of reasonable directivity having thicknesses that are fractions of wavelengths. Properly designed antennas may exhibit bandwidths of an octave or more from the standpoint of the realized gain [4, p.29, (2.321)] keeping the realized gain greater than 0 dBi over one or more octaves.
Specifically, the intent of this solicitation is to model and create low-profile antennas. These antennas should have a thickness that does not exceed 1/30th of the wavelength in free space for the lowest operating frequency of the antenna and the antenna should maintain a realized gain greater than 0 dBi over one or more octaves. The antenna should be realized using use magneto-dielectric layer(s) having anisotropic /inhomogeneous constitutive parameters. It is presumed, but not required, that the anisotropic /inhomogeneous (effective) constitutive parameters are achieved through the use of metamaterials. The antenna should be operational in the VHF/UHF range. Any solution that achieves these antenna goals is desired.
The use of high relative permeability and permittivity materials sandwiched between the radiating element (e.g., a dipole, bow tie, Archimedean spiral, etc.) and an electric ground plane allows the radiating element to be in close proximity to a ground plane while maintaining reasonable input impedance for matching purposes . A fundamental problem with such geometry is the excitation of lateral (surface waves) [3, p. 736] that may guide a significant percentage of the power to the edges of the antenna before scattering into space. Presuming the antenna structure is contained in some type of enclosure (often metallic), these lateral waves may contribute to unwanted internal resonances having a deleterious effect on both the impedance match and the antenna’s radiation pattern. Accordingly, the antenna may not perform as needed from the standpoint of efficiency or the stability of the radiation pattern broadside to the antenna.
A possible solution to the aforementioned problem would employ a magneto-dielectric layer having anisotropic/inhomogeneous constitutive parameters. Properly tailored, such a layer could enhance a frequency independent antenna design while mitigating (or exploiting) the lateral wave excitations. A magneto-dielectric layer created of anisotropic metamaterials (having graded unit cell parameters) is one possible realization of such geometry. In general, the layer may have constitutive parameters that are anisotropic as well as inhomogeneous for both the permittivity and permeability. As frequency independent antennas inherently use the entire element at the lowest frequency while using less of the element as the frequency increases, the gain and input impedance remain reasonably constant [2, p. 611]. The anisotropic /inhomogeneous prescription for the metamaterial magneto-dielectric should be developed in such a way as to keep the efficiency of the antenna as high as possible while maintain a good impedance match over an octave (or more) frequency band. Clearly, the “antenna” must be considered to be the entire structure consisting of the ground plane, magneto-dielectric, and the excitation element.
The realization of the anisotropic /inhomogeneous magneto-dielectric layer is further complicated by the inherent problems associated with the ferromagnetic resonance of the magnetic material and the associated magnetic loss tangent. Practical realizations of an antenna are likely to be limited to frequencies under 1 GHz.
PHASE I: Demonstrate through computer simulations and/or analysis the viability of using a choice material, such as anisotropic/inhomogeneous magneto-dielectrics, to enhance absolute antenna gain. Such an analysis, over an octave bandwidth, should demonstrate stability of the input impedance (<-10 dB return loss) as well as stability of the radiation pattern across the frequency band. The realized gain (dBi or dBic) should remain positive and not exhibit significant decreases in the broadside direction within the frequency band of at least one octave anywhere in the VHF/UHF range. The demonstration should be for a low-profile antenna having a depth of a small fraction of wavelength at the lowest frequency of operation. Demonstrate the material properties simulating or measuring a small sample of inhomogeneous material to the government with accompanying measured data. Additionally, the demonstration should indicate that the antenna will be suitable for transmit (up to 50 W) as well as receive.
PHASE II: Fabricate prototype antennas from the choice material, such as inhomogeneous magneto-dielectric material , demonstrated in Phase I. Measure their RF performance (reflection coefficient, radiation pattern, gain etc.) and compare measured results with commercially available antennas in the same frequency band to establish a reasonable benchmark of performance. Refine antenna fabrication to minimize the volume of magneto-dielectric material to mitigate cost while maintaining antenna performance. At least one working antenna prototype with measured data should be delivered to the government. The antenna must be suitable for both transmitting and receiving, so the ability to contend with power levels up to 50 W on transmit and low-noise temperature on receive should be demonstrated. Designs may be for linear polarization, but must not preclude the more desirable circular polarization.
PHASE III: Phase III will focus on the transition of selected low-profile antenna design(s) onto military platforms such as MRAP, UAV wing, and/or onto commercial platforms such as vehicular and airborne. Address fabrication cost and volume challenges that are relevant to this platform transition. Specific RF applications that may be targeted for these antennas include terrestrial communications, tactical satellite communications, radar, GPS, and RF sensors.
1. Yousefi, L., Mohajer-Iravani, B., Ramahi, O. M., “Enhanced Bandwidth Artificial Magnetic Ground Plane for Low-Profile Antennas”, Antennas and Wireless Propagation Letters, Volume 6, pp. 289-292, 2007. 6>