Tag Archives: medical

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

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