Biomedical subjects

Glenn D Boreman

Publications and source records attributed to Glenn D Boreman.

5 recordsLinked to original sources

PubMed2006

Demonstration of a single-layer meanderline phase retarder at infrared.

Meanderline wave plates are in common use at radio frequencies as polarization retarders. We present initial results of a gold meanderline structure on a silicon substrate that functions at a wavelength of 10.6 microm in the IR. The measured results show a distinct change in the polarization state of the incident beam after passing through the device, inducing a 74 degrees phase retardance between horizontal and vertical components. A high degree of polarization (88%) is maintained in the transmitted beam with an overall power transmittance of 38% and a beam profile that remains essentially unchanged.

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PubMed2006

Millimeter wave imaging system for land mine detection.

Applications using millimeter wave (mmW) and THz radiation have increased during the past few years. One of the principal applications of these technologies is the detection and identification of objects buried beneath the soil, in particular land mines and unexploded ordnances. A novel active mmW scanning imaging system was developed for this purpose. It is a hyperspectral system that collects images at different mmW frequencies from 90 to 140 GHz using a vector network analyzer collecting backscattering mmW radiation from the buried sample. A multivariate statistical method, principal components analysis, is applied to extract useful information from these images. This method is applied to images of different objects and experimental conditions.

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PubMed2005

Comparison of relative signal-to-noise ratios of different classes of imaging spectrometer.

The continued development of new and fundamentally different classes of imaging spectrometer has increased both the scope and the complexity of comparisons of their relative signal-to-noise ratios. Although the throughput and multiplex advantages of Fourier-transform spectrometers were established in the early 1950s, the application of this terminology to imaging spectrometers is often ambiguous and has led to some confusion and debate. For comparisons of signal-collection abilities to be useful to a system designer, they must be based on identical requirements and constraints. We present unambiguous definitions of terminology for application to imaging spectrometers and comparisons of signal-collection abilities and signal-to-noise-ratios on a basis that is useful to a systems designer and inclusive of six fundamentally different classes (both traditional and novel) of imaging spectrometers.

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PubMed2004

Infrared antennas coupled to lithographic Fresnel zone plate lenses.

Several designs for Fresnel zone plate lenses (FZPLs) to be used in conjunction with antenna-coupled infrared detectors have been fabricated and tested. The designs comprise square and circular FZPLs with different numbers of Fresnel zones working in transmissive or reflective modes designed to focus infrared energy on a square-spiral antenna connected to a microbolometer. A 163x maximum increase in response was obtained from a 15-zone circular FZPL in the transmissive mode. Sensor measurements of normalized detectivity D* resulted in a 2.67x increase with FZPLs compared with measurements made of square-spiral antennas without FZPLs. The experimental results are discussed and compared with values obtained from theoretical calculations.

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PubMed2002

Influence of dielectric substrate on the responsivity of microstrip dipole-antenna-coupled infrared microbolometers.

We report on the influence of the dielectric substrate on the performance of microstrip dipole-antenna-coupled microbolometers. The location, the width, and the magnitude of the resonance of a printed dipole are altered when the dielectric substrate is backed by a ground plane. A thicker dielectric substrate shifts the antenna resonance toward shorter dipole lengths and leads to a stronger and slower detector response. The incorporation of an air layer into the antenna substrate further increases thermal impedance, leading to an even stronger response and shifting the antenna resonance toward longer dipole lengths.

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