Showing papers by "Norman S. Kopeika published in 2013"

W-Band Chirp Radar Mock-Up Using a Glow Discharge Detector

Abstract: Chirp or frequency-modulated continuous-wave (FMCW) radar is a very well-known method for range applications. Using the current technology, conventional FMCW radar for W-band waves requires the use of expensive microwave mixers and low noise amplifiers (LNA). A uniquely simple and inexpensive solution is presented using very inexpensive glow discharge detectors (GDDs). The use of GDDs enables direct beating between the electric field of the target signal and the reference signal eliminating the requirement for expensive millimeter wave mixers, sources, and LNAs. This unique solution to FMCW radar is proven to be capable of determining range to target, and creating 3-D radar images. In this paper, a proof of concept of chirp/FMCW radar detection using a GDD in the W-band regime is demonstrated experimentally. The GDD chirp radar system has the following advantages: 1) much simpler realization in short range applications; 2) rigid, room temperature operation; 3) sub-microsecond response time; 4) large dynamic range; and 5) immunity to high-power radiation.

Heterodyne detection at 300 GHz using neon indicator lamp glow discharge detector.

Abstract: A miniature neon indicator lamp, also known as a glow discharge detector (GDD), costing about 50 cents, was found to be an excellent room temperature terahertz radiation detector Proof-of-concept 300 GHz heterodyne detection using GDD is demonstrated in this paper Furthermore, a comparison to direct detection was carried out as well Previous results with the GDD at 10 GHz showed 40 times better sensitivity using heterodyne detection compared to direct detection Preliminary results at 300 GHz showed better sensitivity by a factor of 20 with only 56 μW local-oscillator power using heterodyne compared to direct detection The higher the local-oscillator power (P(lo)), the better the sensitivity of the detector Further improvement can be achieved by employing better quasi-optical design

Performance quantification of a millimeter-wavelength imaging system based on inexpensive glow-discharge-detector focal-plane array

Abstract: Inexpensive millimeter-wavelength (MMW) optical digital imaging raises a challenge of evaluating the imaging performance and image quality because of the large electromagnetic wavelengths and pixel sensor sizes, which are 2 to 3 orders of magnitude larger than those of ordinary thermal or visual imaging systems, and also because of the noisiness of the inexpensive glow discharge detectors that compose the focal-plane array. This study quantifies the performances of this MMW imaging system. Its point-spread function and modulation transfer function were investigated. The experimental results and the analysis indicate that the image quality of this MMW imaging system is limited mostly by the noise, and the blur is dominated by the pixel sensor size. Therefore, the MMW image might be improved by oversampling, given that noise reduction is achieved. Demonstration of MMW image improvement through oversampling is presented.

Oversampling advances in millimeter-wave scan imaging using inexpensive neon indicator lamp detectors

Abstract: In recent years, much effort has been invested to develop room temperature inexpensive, but sensitive, millimeter wave (MMW) and terahertz (THz) detectors that can be used as pixels in focal plane arrays, which is important for real-time imaging. A new 18×2 neon indicator lamp MMW/THz scanner was developed. The components of the camera include horizontally shifted two-column glow discharge detectors in a scanning array. The detectors, costing about 50 cents each, are wired to a preprocessing card, a VLSI board, and a motor for scanner movement. A description of the VLSI Verilog programmable hardware of the new scanner, the physical architecture, the software user interface, and imaging results at 97 GHz are presented. At this stage, the emphasis is focused on the lamp exposure time and spatial resolution when the scanning is performed horizontally. In the future it is planned to expose all pixels simultaneously for real-time imaging. New software capabilities allow the application of digital image enhancement algorithms. Fast scanning permits obtaining images in 1 to 5 s. Oversampling yields a sharper edge response and a higher signal-to-noise ratio.

Heterodyne detection at 300 GHz using glow discharge detectors with efficient quasi-optical design

Abstract: A miniature neon indicator lamp, also known as a Glow Discharge Detector (GDD), costing about 50 cents, was found to be an excellent room temperature THz radiation detector. A proof of concept of 300 GHz heterodyne detection using GDD is demonstrated in this paper. Furthermore, a comparison to direct detection was carried-out and polarization effects on heterodyne detection were investigated. Preliminary results at 300 GHz showed better sensitivity by a factor of 20 with only 56 microwatt local oscillator power using heterodyne compared to direct detection. Further improvement of the detection sensitivity can be achieved if the Local Oscillator (LO) power (Plo) is increased. Effects of orthogonal polarizations of signal and local oscillator powers on heterodyne sensitivity were found to be surprisingly weak. More efficient quasi optical design for heterodyne detection is presented in this study, experimental results showed above 50% better performance compared to conventional ones.

Blind source separation of images based upon fractional autocorrelation

Abstract: Blind source separation (BSS) is a process in which mixed signals are separated into their original sources. Both the sources as well as the mixing coefficients are unknown but a priori information about statistical behavior and about the mixing model might be available. We here suggest a generalization of our previous research that showed a new BSS algorithm based on general cross correlation linear operators applied on the sources that are to be separated. In that approach in cases of negligible cross-correlation between the source signals, a very good separation could be obtained. Here we propose to use the fractional Fourier transform in order to reduce the correlation between the source signals and to further enhance the obtained separation performance. We present reduced dependence on the cross-correlation between the source images, resulting in better separation of the mixed sources.

3D Millimeter Wave imaging system using chirp radar and Glow Discharge Detector pixel

Abstract: Demonstration of Millimeter Wave (MMW) imaging system using chirp radar method and Glow Discharge Detector (GDD) Focal Plane Array (FPA) is presented. A unique quasi optical set up and advanced detection methods using the GDD are intended to build the 3D MMW imaging system. This quasi optical setup enables to detect the distance and reflection of each point in object in order to reconstruct a 3D MMW image.

Heterodyne detection and polarization effects at 300 GHz using Ne indicator lamp glow discharge detectors

Abstract: A miniature neon indicator lamp, also known as a Glow Discharge Detector (GDD), costing about 50 cents, was found to be an excellent room temperature THz radiation detector. A proof of concept of 300 GHz heterodyne detection using GDD is demonstrated in this paper. Furthermore, a comparison to direct detection was carried-out and polarization effects on heterodyne detection were investigated. Preliminary results at 300 GHz showed better sensitivity by a factor of 20 with only 56 microwatt local oscillator power using heterodyne compared to direct detection. Further improvement of the detection sensitivity can be achieved if the Local Oscillator (LO) power (Plo) is increased. Effects of orthogonal polarizations of signal and local oscillator powers on heterodyne sensitivity were found to be surprisingly weak.