Category Archives: Security & Identification

Biometrics, forensics, law enforcement, threat detection, etc.

NOx Sensor with Improved Selectivity and Parts-Per-Billion Sensitivity

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Summary:

Nitrogen Oxides (NOx) present a host of environmental and health problems, including acid rain, urban smog, acidification of lakes and streams, and damage of forest soils.  The major source of NOx is from the combustion of fossil fuels, and NOx sensors are employed in the development of internal combustion engines in order to optimize combustion and minimize emissions.  Nitric Oxide is also an important biological molecule and its level in human breath is also an indication of many diseased states, including asthma.

Resistance-based electrochemical NOx sensors, while exhibiting good sensitivity, often react to many different gases, and selectivity suffers.  Potentiometric sensors offer a promising approach for NOx measurements in harsh environments, but often suffer from interference with other gases.

Researchers at The Ohio State University have developed a novel potentiometric NOx sensor that overcomes the interference limitations of previous potentiometric sensors.  This sensor is extremely selective to NOx in the presence of other gas species, and sensitivities have been confirmed in the parts-per-billion range!  The sensor is ideal for incredibly precise NOx measurements in environments as diverse as engines and for breath monitoring.

Potential Applications:

  • Medical diagnostics
  • Combustion optimization
  • Environmental NOx monitoring

Advantages:

  • Ridiculously high sensitivity (ppb range!)
  • Excellent selectivity
  • Will withstand extreme environments
  • Cost effective as potentiometric output does not require sophisticated support electronics

Resonant Interband Tunneling Diodes–Extending Moore’s Law and Enabling New Circuitry

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Summary:

Since the early 1960’s, the utility of the tunnel diode (or Esaki diode) has been evident, but several practical hurdles have kept it from reaching mainstream status. Historically, it has been difficult to control peak current and, more importantly, tunnel diode fabrication has lacked a Si-based process that can easily be mass produced and integrated into existing Si-based integrated circuits. As a result, today’s tunnel diodes are primarily used in discrete form and for niche applications. Regardless, tunnel diodes have many current and future applications, and the challenges of aggressively scaled CMOS is forcing this subject to be seriously revisited, since quantum tunneling will dominate in any ultra-low dimensional material. The structure of the Resonant Interband Tunneling Diode (RITD) differs from that of the Esaki diode (traditional tunnel diode) which results in additional useful properties. In RITDs, electrons quantum mechanically tunnel across an energy well formed between two barriers, where Esaki diodes have no energy well. This quantum mechanical tunneling effect happens extremely quickly and thus very high speed electronics can be realized with the use of RITDs. Terahertz operation has been demonstrated. Furthermore, a useful effect called Negative Differential Resistance (NDR) can be exploited using these devices.

Potential Applications:

  • Can augment CMOS technology resulting in novel logic and embedded circuit topologies with reduced device count, low power, and faster speed.
  • Can be implemented in ICs, memory devices, and small, lightweight portable electronics for greater performance at lower power consumption
  • Applications found in oscillators, frequency locking circuits, advanced SRAM circuits, highly integrated A/D converters, high speed digital latches, and many others

Advantages:

  • Uses quantum tunneling, a very high-speed process. Terahertz operation has been demonstrated
  • Shown to exhibit Negative Differential Resistance (NDR)
  • Low cost, compatible with current CMOS technology, and easy to integrate into existing manufacturing processes
  • Runs at room temperature and at very low voltage
  • Can be combined with existing technologies to offer flexibility

IP Status:

Tunneling Diode: Use and Manufacturing – US Pending
Using Backward Tunneling Diode as a Sensor – US Pending

Method for Dynamic 3D Wavelet Transform for Video Compression

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Summary:

Video is a data-rich medium that results in the creation of large data sets requiring large memory spaces and wide bandwidth to transmit. At The Ohio State University, we have created a dynamically grouped, 3D wavelet technology which significantly reduces the bit-rate for transmitting or storing audio, video and image signals, and out-performs existing technologies in terms of compression efficiency, image quality and scope of applications. Demonstration software is available.

Potential Applications:

  • Streaming internet or wireless video and audio transmission
  • Mobile phone video
  • Video conferencing
  • Video on demand
  • Digital video surveillance
  • Multi-media email
  • Video databases and archiving
  • Digital video editing

Advantages:

  • Higher compression ratios than other techniques (e.g. discrete cosine transform based MPEG), while maintaining superior image quality
  • Adaptive grouping 3D system for enhanced compression ratios
  • Separate object and background compression
  • Packed-integer implementation of wavelet transform for high-speed computation
  • Software only solution
  • Amenable to VLSI or DSP hardware implementations
  • Suitable for handheld devices, since integer based computation allows for low power IC use
  • Flexible algorithm facilitates tuning to available computational resources

IP Status:

US Patent No.: 6,801,573 (October 5, 2004)

Digital Method for Real-Time Frequency Evaluation of Periodic Signals

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Summary:

Frequency counters typically count a frequency of a periodic signal by setting a set gate level. Each time the periodic signal crosses the gate level an event is generated. After calculating the number of events per second, the frequency is then calculated from the periodic signal. Unfortunately, this universal method has not demonstrated stability for frequency measurements. At The Ohio State University, we have created a reliable digital real-time method that detects frequency of a force signal from a microcantilever sensor in Magnetic Resonance Force Microscopy. Additionally, this method demonstrates sensitivity limited only by the displacement noise of a cantilever. Our high precision evaluation of the frequency of a periodic signal can be used as an extra option for any currently available digital signal processing hardware. A prototype is available for testing and evaluation under a confidentiality agreement.

Potential Applications:

  • Detection of biohazards at sensitive immigration and import/export points and at transportation sites
  • Counter intelligence and eavesdropping
  • Breathalizers
  • Any SFM system, MRFM, MRI, and microwave signals

Advantages:

  • Measures frequency shifts of resonator cantilever quickly thus offering increased sensitivity.
  • Continuously measures rather than sampling because it measures in small forces that are 6-7 magnitudes larger than what needs to be measured.
  • Accurately and directly calculates the frequency from the amplitude and the phase of an input signal.
  • The frequency signal is based upon a number of points less than the period of a signal.
  • Enables higher force sensitivity for force microscopy systems and for noise where force is detected through its influence upon the frequency of the oscillating mechanical force detector (microcantilever).
  • Solves the problem of limited bandwidth of amplitude detection.
  • Most effective sound frequency range is DC-1MHz.
  • One can resynchronize by re-inputing data that was taken out of the probe sequence so one can probe the system with the probe sequence.
  • Allows one to create a full MRFM measurement system including a self excitation circuit, a frequency detector, and RF modulation circuits and capable of generating modulation signals whose phase is locked to the cantilever signal.
  • Existing computers already use digital computers.
  • Digital read-out of frequency output time is 4 milliseconds; as computer boards improve, this technique’s speed improves.

Undetectable, Unjammable, and Interference-Free Ultra Wideband Radar System

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Summary:

Researchers at the Ohio State University have developed a virtually undetectable ultra wide band radar system that transmits pseudo random noise. On receive, the radar system cross-correlates a copy (possibly modified) of the original waveform with the receive signals. If a target reflects the signal (with modifications) then the radar will detect the reflection, the time delay, and Doppler. Thus the radar can tell the distance to a reflecting object and its relative speed. This is done using a waveform that will not interfere with other users of the spectrum. The noise waveform is extremely hard to detect. Researchers have further developed a system of storing the waveforms and performing the cross correlation at a particular time delay using a single memory device and no delay devices. This lends to the creation of a small, low cost, low power, stealthy radar that cannot be easily detected by conventional radar detection equipment and can be used for very short range applications. The radar can also be used to identify radar targets by using a pair of waveforms matched to the target radar impulse response. Thus the radar can also be used to detect only specific types of targets, as maybe required by the application.

Potential Applications:

  • Speed radar gun manufacturers seeking an undetectable radar gun
  • Simple moving vehicle/person/object with identification potential (automotive lane change warning)
  • Highway management to evaluate strength of material, or helicopter air to air warning systems
  • Low cost ground penetration radar for pipes, land mine detection, or probing human bodies
  • Low cost building penetration radar (security systems at casinos and airports)
  • Cross section instrumentation radar with inverse synthetic aperture imaging radar ability
  • Moving Radar, synthetic aperture radar systems

Advantages:

  • Robust with reference to interference or jamming – thus undetectable and hard to intercept
  • Unlikely to interfere with other noise radar systems or other radar systems in the same band
  • Low cost, small, light weight, and can be used for very short-range applications
  • Can be trained to be target specific (with the ability to specify multiple targets)
  • Would require no license to operate in civilian bands, and is fully coherent in amplitude and phase

Electrospun Fiber-Coated Solid Phase Microextraction Fibers

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Summary:

Current solid-phase microextraction coating technology is an expensive and tedious process. Ohio State researchers have discovered a method to use electrospun fiber-based coatings for solid phase microextraction. This method greatly simplifies the process and costs less.

Potential Applications:

  • Laboratory chromotography
  • Sensing element for portable biohazard and chemical detectors

      • Advantages:

      • Larger range of surface functionalities
      • Higher surface areas
      • Thinner coatings
      • Higher sample capacities

Simple, cost-effective, flexible system for micro/nano particle manipulation

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Summary:

The availability of mobile magnetic traps offers new control needed for rapid progress at the frontiers of several branches of science and engineering. Ohio State researchers have discovered a way to create tunable mobile traps along a nanowire, which allows the manipulation and movement of nanoparticles along the wire. The femto- to pico-Newton scale forces possible with this method, which are delivered using electric currents, are ideally suited for probing single microparticles and biomolecules in the 10 nanometer to 100 micrometer length scales. Additionally, the nanoparticle(s) can be tethered to larger molecules, allowing manipulation of the larger molecules. As an example, a DNA strand could have each end attached to separate nanoparticles and then stretched as the nanoparticles are moved away from each other.

Potential Applications:

  • Clinical diagnosis
  • Biomolecule analysis
  • Forensics
  • Enviromental analysis
  • Nanofluidics

Advantages:

  • Easy to engineer magnetic domain
  • Simple and accurate manipulation of nanoparticles
  • Real-time observation of single or multiple objects trapped along the nanowire
  • Uses electric currents to transport along predetermined pathways
  • Two or more functionalized particles at the mobile traps can be linked to create a planar magnetic tweezer stage

Emulating Metamaterials Using a Simple Printed Microstrip Design

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Summary:

Researchers at the Ohio State University’s ElectroScience Laboratory have been able to use simple (printed on uniform substrates) microwave circuit components to emulate the extraordinary propagation phenomena traditionally encountered in photonic crystals and metamaterials. These materials have been shown to exhibit unique and useful properties for microwave and optics applications such as delay lines, couplers, and antennas. One class of these structures demonstrated significant wave slowdown and amplitude increase within a small region, leading to miniaturization of antennas and other microwave circuit components. Another important property of metamaterials that has attracted significant research interest is the realization of a negative index of refraction. As the latter are difficult and expensive to manufacture, the proposed technology provides a practical approach to realize such unique properties. The researchers have already been able to realize these extraordinary properties using uniquely invented, cost effective, and easy to manufacture microstrip transmission lines arrangements.

Potential Applications:

  • Enables easy and inexpensive miniaturization of microwave and optical circuit components such as coupled lines, delay elements, phase shifters, printed antennas, antenna arrays, and solid state semiconductor optoelectronic devices
  • Enjoys the benefits derived from photonic crystals and metamaterials at a fraction of the cost
  • Enables a boost in gain while maintaining the same size dimensions

Advantages:

  • Compared to photonic crystals and metamaterials, this structure is much more cost effective and easier to manufacture, while exhibiting similar properties
  • Easy to retrofit with existing manufacturing processes and manufacture in volume since it is based on printed circuit technology

Ultra-Wide Band, Electrically Small Antennas

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Summary:

There is great commercial interest for antennas that can operate over large frequency bands. This is especially true for electrically small antennas (small in terms of wavelength). Designing effective, wide bandwidth, electrically small antennas is one of the most challenging problems in antenna engineering. Researchers at the Ohio State University have invented a method for appropriately loading the antenna at various locations along the structure with reactive elements (capacitors and inductors) which can have negative values (non-Foster elements) and can greatly increase the bandwidth of the antenna by controlling its currents. This concept is more general than previously reported methods based on the design of matching networks, which are based on the current and voltage behavior at the antenna terminals only. In contrast, this invention deals with currents throughout the entire antenna structure and results in an antenna with a simple and small form factor, ideal for miniature or portable electronics that require a small footprint.

Potential Applications:

  • Handheld/portable electronics developers/manufacturers
  • Printed electronics developers/manufacturers
  • Defense applications
  • Medical sensing applications
  • Wireless sensor networks/scalable data fusion sensor networks

Advantages:

  • Yields Ultra-Wide-Band (UWB) antennas with a simple and small form-factor
  • Solves the narrow bandwidth problem that exists for electrically small antennas
  • Preserves the same pattern shape over the desired frequency range
  • Superior to designs based on matching networks
  • Enables a systematic, general design methodology for antenna loading

Methods and Systems for Ultra-Precise Measurement and Control of Object Motion in Six Degrees of Freedom

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Summary:

In microelectromechanical systems (MEMS), microelectronic fabrication techniques have led to mostly planar parts having dimensions in the vertical direction of only a few micrometers. Multi-scale 3-D devices, whose components range in size from several millimeters down to nanometers, are believed by many researchers and practitioners to potentially have a much greater range of applications than MEMS in a wide range of industries including medicine, communications, defense, aerospace, and consumer products. Metrology, manipulation, and testing of these devices have proven to be a significant barrier to their further development. To overcome this barrier, researchers at The Ohio State University have developed a visual sensing method and system that provides the full pose of multiple 3-D micro objects with under 10 nanometer precision in x-y-z. Furthermore, the system can automatically perform positioning and alignment of micro objects in real time using measurements derived from a single image, so that no scanning is necessary to obtain ‘out-of-plane’ motion parameters. Applications include dynamic alignment of micro parts, assembly of micro-optical and micro-mechanical components, and assembly of micro sensors, among others.

Potential Applications:

  • Micro-assembly and manipulation station developers
  • Sensor and measurement system manufacturers
  • R&D workstation developers

Advantages:

  • Provides the full pose of multiple 3-D objects with under 10nm precision in x-y-z
  • The six-degree-of-freedom motion of each micro object is measured from a single image so that no scanning is necessary to obtain ‘out-of-plane’ motion parameters
  • Allows automatic real-time positioning and alignment of micro-objects
  • Can serve as a compact motion sensor and can be employed to achieve direct metrology and direct visual servo control in the object space with nanometer resolution