Category Archives: Technology

Independently Fed AM/FM Heated Window Antenna

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Summary:

Dr. Eric Walton of the ElectroScience Laboratory at The Ohio State University has developed an automotive antenna that is effectively incorporated into the resistive, conductive heating elements found in automotive windows. The automobile industry has long recognized the advantages of forming an antenna in a vehicle window by imbedding conductors in the window glass. Manufacturers have also recognized that such windows can be defogged or defrosted by distributing resistive conductors over a major portion of the window area (the familiar heater grid found on the rear window of automobiles). It has been realized that the same conductors may be used for both heating the window area and as the communications antenna. The challenge lies in that the heater power source must be isolated from radio frequency signals in order to prevent RF currents from being shorted through the vehicle or heater power system. Previous attempts at isolation have been successful but have resulted in the need for heavy, expensive components and the need for separate antennas for different frequency bands. Dr. Walton’s design allows for optimal AM/FM reception (or the reception of other relatively low and high frequency bands found in modern wireless communication) and impedance matching using a single antenna, whereas previous designs required the use of two separate, different antennas. The design further allows for an apparatus with reduced size, weight, and cost as compared to previous methods. When coupled with U.S. Patents #6,320,558 and #6,483,468 (On-Glass Impedance Matching Antenna Connector, Reference #99062), impedance matching in the AM and FM bands can be easily achieved and a complete on-glass automotive AM/FM antenna/heater grid configuration realized.

Potential Applications:

  • A sleek, lightweight, and low-cost antenna solution that is integrated into existing heater grid configurations
  • When coupled with U.S. Patents #6,320,558 and #6,483,468 (On-Glass Impedance Matching Antenna Connector, Reference #99062), impedance matching in the AM and FM bands can be easily achieved and a complete on-glass automotive AM/FM antenna/heater grid configuration realized

Advantages:

  • Effectively incorporates an antenna into a vehicle’s heater grid system
  • Allows for the reception of multiple bands with large frequency separation
  • Provides a smaller, lighter, lower-cost alternative to previous methods

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

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.

Direct, Low Frequency Capacitance Measurement for Scanning Capacitance Microscopy

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Summary:

Scanning capacitance microscopy (SCM) circuits, used for such applications as semiconductor characterization (including dopant profiling, device characterization, and surface defect characterization), are typically not adapted for calibrated, low frequency measurements of absolute capacitance. In fact, these implementations of SCM generally do not measure capacitance directly. Rather, they measure the change in capacitance versus the change in voltage (dC/dV) by varying the probe-sample voltage V at frequencies greater than 10 kHz. This is due to a voltage dependant capacitance resulting from a voltage-dependant space change layer in the semiconductor substrate. The Ohio State University has developed a system and method for performing scanning capacitance microscopy using an atomic force microscope (AFM) that measures direct capacitance at a frequency less then 10 kHz. The system exhibits high sensitivity with very low noise. Recent advancements to this technology have resulted in even higher sensitivity by enabling direct measurements of absolute capacitance at higher frequencies. The design of the circuit has also been simplified, enabling the use of off-the-shelf components such as function generators. This straightforward design will shorten the investment of time and money needed to commercialize this powerful system.

Potential Applications:

This system is an ideal tool for semiconductor characterization. It is also useful for measuring a wide variety of dielectric films such as SiO2 grown on Si, or for dielectric films on other semiconductor substrates such as Si3N4, Al2O3, TiO2, and ZrO2. It may also be used to measure thin lubricant films such as perfluoropolyethers, a widely used class of compounds for MEMS and hard disk drive lubrication. Other suitable types of samples include self-assembled monolayers.

Advantages:

  • Enables direct capacitance measurements at low frequencies
  • Low noise
  • High sensitivity
  • Straightforward yet powerful design
  • Can also determine stray capacitance

On-Glass Impedance Matching Antenna Connector

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Summary:

Dr. Eric Walton of the ElectroScience Laboratory at The Ohio State University has developed a way to connect an on-glass antenna to a transmission cable that overcomes impedance matching problems in the AM and FM bands. Impedance matching for on-glass antennas is a challenge since in the FM frequency band coaxial cable impedance is often 50 ohms, and in the much lower AM frequency band the antenna and the receiver input impedance is much closer to 6,000 ohms. This invention results in a wide bandwidth and a transformation from the coaxial cable impedance to the antenna impedance. The matching circuit is especially designed to be imbedded in a small window attachment clip. This invention would be particularly suited for use in automobiles where the rear window heater grid can also function as an antenna, and consequently is essential along with another of Dr. Walton’s inventions which is described in U.S. Patent #5,781,160 (OSU Reference #94048). It should be noted, however, that this method is applicable in other on-glass wideband antenna configurations where impedance matching in the AM and FM bands must be achieved.

Potential Applications:

  • An elegant and cost-effective impedance matching solution in the AM and FM bands for automotive antenna manufacturers
  • When coupled with U.S. Patent #5,781,160, a complete AM/FM on-glass automotive heater grid/antenna system can be realized

Advantages:

  • Allows for easy, convenient impedance matching for printed on-glass AM/FM antennas

Device and Method for Producing Optically-Controlled Incremental Time Delays

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Summary:

Generating precise and reliable true time delays (TTDs) is of paramount importance for phased array radars and a host of other applications. True time delay avoids beam squint in wideband antenna systems. Researchers at The Ohio State University have developed a free-space optical TTD device that can provide many bits of delay (more than 15 bits) for hundreds of antenna elements in ultra-compact form (half a cubic foot) with delays varying from femtoseconds to tens of nanoseconds. The invention uses a single MEMS chip, free space for massive overlapping of beam space, and a handful of mirrors. A programmable tapped delay line has many other uses, including optical correlation, optical matched filtering, optical signal processing, optical code-division multiple access coding and decoding, photonic analog-to-digital conversion, and optical communications performance monitoring. A variation of the device can also be used for optical interconnections and routers. Electronically implementing TTDs is generally impractical because of the need for many long lengths of strip line, waveguides, or coaxial cable, which are expensive, bulky, and temperature sensitive. Since long path lengths are relatively easy to obtain optically, optical TTD systems have been developed, either using fibers or free-space paths, but these existing systems are expensive and bulky due to the use of multiple optical switches. Researchers at The Ohio State University have developed a free-space optical TTD device that uses only one optical switch or spatial light modulator for the entire system instead of one or more switches for each bit, as in previous systems. Furthermore, the device avoids beam-spreading problems that may be present in other free-space systems by using a multiple-pass optical cell with refocusing mirrors. As a result, the device is more inexpensive, compact, and temperature insensitive than existing devices.

Potential Applications:

  • Optical multiplexing/demultiplexing applications
  • Optical routing and switching
  • Phased array radars
  • Optical signal processing
  • Optical performance monitoring

Advantages:

  • Uses only one optical switch or spatial light modulator
  • Ultra-compact form factor
  • Small component count

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

Two-Layered Micro Channel Heat Sink Concept in Electronic Cooling

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Summary:

Heat removal has become an important factor in the advancement of microelectronics due to drastically integrated density of chips in digital devices and increased current-voltage handling capability of power electronic devices. Micro-channel heat sinks remove heat 50 times more efficiently than conventional methods. However, one-layered micro-channel heat sinks induce high temperatures which can produce thermal stress on the chips and packages. To avoid such high temperatures, a large pressure drop is necessary which moves the coolant through the cooling channels more rapidly, thus requiring a larger, noisier pumping system. Scientists at The Ohio State University have developed a multi-layered micro-channel heat sink with a current flow arrangement for cooling that is a substantial improvement over conventional one-layered micro-channel heat sink designs. The thermal performance and the temperature distribution for these types of micro-channels were analyzed and a procedure for optimizing the geometrical design parameters was developed. While the power supply system of the multi-layered design is not significantly more complicated than the one-layered design, the stream-wise temperature rise on the base of surface was substantially reduced. At the same time, the pressure drop required for the multi-layered heat sink was substantially smaller than the one-layer design. It is shown that the thermal resistance is as low as 0.03 ?C/W for micro-channel heat sinks, which is substantially lower than conventional channel-sized heat sinks.

Potential Applications:

The multi-layered micro-channel design is ideal for the electronics semiconductor industry. More efficient cooling of solid-state radar systems, diode lasers, and mainframe and supercomputers are just a few of the applications. Using this technology for laser cooling is simpler than for microelectronics cooling. Research has demonstrated that the method works quite well for surfaces with a diameter of roughly up to 10 cm.

Advantages:

  1. Cools far more efficiently than conventional cooling methods
  2. Cools surfaces as well as single-layer micro-channels but holds two noticeable improvements in efficiency:
    1. Stream-wise temperature rise on the base of surface is substantially reduced compared to single-layer micro-channels.
    2. Pressure drop required for the multi-layered heat sink is substantially smaller than the single-layer design.
    3. Size of coolant pumping system is reduced.

Low-Cost, Fast, and Accurate System to Test Wire Pattern Continuity

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Summary:

Dr. Eric Walton of the ElectroScience Laboratory at the Ohio State University has developed a system for testing a conductive pattern that is fast, inexpensive, and accurate. Conductive patterns are found in a wide range of everyday products, from electronics to automobiles. One common application of a conductive pattern is the defroster/defogger on the rear window of an automobile. As the conductive wire patterns in these windows become more complex, methods of testing the continuity and quality of these patterns becomes more difficult and expensive. It is important that the testing system be robust enough to easily handle complex changes in pattern design, accurate enough to meet engineering standards, and inexpensive enough to be cost-effective to the manufacturer. This invention meets and exceeds all of these needs. This invention is just as useful in other applications such as the testing of printed circuit boards, the testing of conductive patterned surfaces used in electroforming, or the testing of any material in which conductive patterns are used for heating.

Potential Applications:

  • Invaluable tool for automotive glass manufacturers who aim to increase efficiency and reduce costs
  • Provides a fast and easy way to test the quality of printed circuit boards
  • A fantastic testing tool for the emerging field of printed electronics using conductive inks, which will find applications in e-readers, RFID tags, and other novel, groundbreaking electronic technologies

Advantages:

  • Reliable as the system is never in direct contact with the material to be tested
  • Inexpensive and easy to modify and/or replace components
  • Extremely accurate
  • Speed limited only by computing power and production capabilities
  • Easily integrated into an automated production line

Instantaneous Monitoring of the Quality of Optical Telecommunications Links

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Summary:

Ohio State researchers have developed a novel method of signal quality monitoring that can reliably assess the quality of a digital signal in as little as 100 picoseconds, thousands of times faster than traditional bit-error rate (BER) or eye diagram testing. The technique compares bit shapes in an all-optical system to detect the combined effects of attenuation, dispersion, noise, and timing jitter. The hardware is simple, compact, and far less expensive than traditional QoS systems. This system allows users of optical links to quickly and accurately assess their data quality. Using this information, more intelligent networks can be designed and implemented.

Potential Applications:

  • Optical performance monitoring
  • Optical routing and switching
  • Digital communication systems (electronic or optical)

Advantages:

  • Compact, simple, inexpensive hardware
  • Orders of magnitude faster than traditional electronic bit error rate measurement
  • Instantaneous monitoring of optical link quality