Category Archives: General Instrumentation

AFM, interferometry, mass spectrometry, STEM, etc.

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

Miniaturizable, High Temperature Oxygen Sensor

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Summary:

In a variety of applications from automobiles to power plants, the optimization of combustion parameters is critical in maximizing efficiency and minimizing harmful emissions.  In fact, it is estimated that yearly savings of over $400 million could be enabled through combustion optimization within coal-fired power plants.  In order to optimize combustion, oxygen levels need to be carefully controlled, which calls for accurate and reliable oxygen sensor technologies.  Such sensor technologies must be able to withstand the high temperatures found in combustion environments while exhibiting the smallest possible footprint.

In order to fulfill this need, researchers at The Ohio State University have developed a miniaturizable, high temperature oxygen sensor that is capable of long-term operation and is resistant to the strains of thermal cycling.  Currently, the sensor can withstand temperatures up to 800 degrees C.  Furthermore, as the sensor does not require reference gas plumbing, there is flexibility in the placement of these sensors in a combustion stream. 

Potential Applications:

  • Automotive
  • Power plants
  • Medical
  • Diving
  • Scientific

Advantages:

  • Cost effective
  • Reliable over long-term operation
  • Can withstand temperatures up to 800 degrees C
  • Miniaturizable
  • Affords flexibility in sensor placement

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

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

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.

Multi-Degree-of-Freedom Nano-Probes: Design, Actuation, and Measurement

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Summary:

In applications such as scanning probe microscopy (e.g. AFM), nano-metrology, and micro/nano manipulation, traditional nano-probes are limited in that their tips have a fixed orientation. As a result, they are useful primarily for near-planar samples. Complex geometrical features or features with large changes in topography can either not be imaged at all or are imaged at greatly reduced lateral resolution with increased artifacts. Researchers at the Ohio State University have developed a novel multi-axis nano-probe that enables high-resolution imaging of 3-D surfaces on arbitrarily complex geometric features and nano-manipulation of 3-D samples. For these applications, the probe enables fast and precise co-located control of tip orientation by several tens of degrees and multi-axis control of probe-sample interaction forces. Together, they allow for controlled 3-D manipulation of soft, sensitive specimens and imaging samples with complex geometry (like re-entrant features and steep side-walls).

Potential Applications:

  • AFM equipment manufacturers
  • Nanometrology instrument manufacturers
  • Nanomanipulation system manufacturers
  • NEMS/MEMS manufacturers

Advantages:

  • Enables control of probe-orientation along two independent axes by several tens of degrees while retaining the probe-stiffness along the Z-axis
  • Compact, high-bandwidth, high-gain actuation for fast, large-angle tip-positioning
  • Enables the measurement of tip orientation angles that are possibly over a hundred times larger than the measurement range of the optical detectors used in scanning probe microscopy while retaining the high resolution of the detectors
  • Enables multi-axis co-located control of probe-sample interaction forces
  • Enables real-time tracking of surface orientation by the probe-tip during 3-D imaging of sample surfaces

Implementation of Light-Free Capacitive Displacement Detection for Magnetic Resonance Force Microscopy

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Summary:

Magnetic resonance signal is detected via displacement detection of a micromechanical cantilever. Usually, this is done by means of fiber-optical laser interferometry. However, in many systems, laser light disrupts magnetic resonance signal. At The Ohio State University, we are the first to implement MRFM with light-free capacitive displacement readout that can perform subsurface imaging on a nanometer scale.

Potential Applications:

  • Solid state quantum computer
  • Semiconducting devices
  • It can detect a range of magnetic resonance phenomena (EPR, NMR, FMR) making it applicable to various physical systems

Advantages:

  • The depth of probing can measure to the nanometer scale to image molecules.
  • Improved sensitivity could exceed optical techniques
  • Capacitive detection will eventually replace optical detection
  • There is no laser light to disrupt the magnetic resonance signal
  • Displacement detection is integrated into the device allowing it to be fabricated at the same time making it enabling for parallelization

Low Temperature Working Carbon Monoxide (CO) Sensor Based on Au/SnO2 Core-Shell Nanoparticles

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Summary:

SnO2-based CO sensors are widely used in domestic and industrial applications and belong to the class of metal-oxide semiconductor (MOS) sensors. This class of sensor is easy to manufacture and miniaturize, and sensitivity and selectivity are both tunable. Also, electrochemical measurements are easily realized, require simple electronics, and integration into electronic devices is straightforward. However, since sufficient oxygen vacancies are needed for conduction, MOS sensors typically operate at elevated temperatures, which requires energy consumption and reduces sensor lifetimes. Researchers at The Ohio State University have developed a MOS CO sensor based on Au/SnO2 core-shell nanoparticles that is operable in the 25 to 150 deg. C range. Sensor response is highly reproducible and recovery is fast in this temperature range, and high sensitivity was exhibited.

Potential Applications:

  • Home, office, and industrial CO monitoring for occupant and fire safety
  • Low temperature and low power requirement makes it compatible with mobile devices

Advantages:

  • A MOS electrochemical CO sensor that operates in the 25 to 150 deg. C range!
  • Increased safety and sensor longevity as no heating device is needed
  • Greatly reduced energy consumption
  • Extremely low cost and easy manufacturing
  • Simple electronics for easy device integration

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

Carbon Monoxide (CO) Detector Operating at Room Temperature

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Summary:

Existing CO sensors are usually of either the electrochemical or optical variety. Inexpensive optical sensors, usually battery powered, are limited in their precision and lack displays to determine exact levels of CO concentration. Electrochemical devices offer higher precision and offer a display for CO concentration, but must operate at elevated temperatures and thus must be plugged in to a wall outlet. Researchers at The Ohio State University have developed an electrochemical CO sensor that operates and senses CO at room temperature, thus eliminating the need for a heating device. Therefore, energy demands are far lower when plugged in to a wall outlet, and a battery-powered electrochemical CO sensor can be achieved. This sensor can monitor CO in the ppm range and can be readily fabricated by screen printing techniques with deposition on polymer substrates. Sensors are miniaturizable.

Potential Applications:

  • Home, office, and industrial CO monitoring for occupant safety and fire detection
  • CO sensors can be incorporated into mobile devices, such as cell phones

Advantages:

  • Increased safety and sensor longevity as no heating device is needed
  • For the first time, battery-powered electrochemical CO sensors are possible
  • A portable, battery-powered CO sensor with a display becomes possible
  • Great reduction in energy consumption
  • Low-cost and easy to manufacture