Abstract-Enhanced MMW and SMMW/THz imaging system performance prediction and analysis tool for concealed weapon detection and pilotage obstacle avoidance

Steven R. Murrill, Charmaine C. Franck, Eddie L. Jacobs, Douglas T. Petkie, and Frank C. De Lucia

https://www.osapublishing.org/ao/abstract.cfm?uri=ao-56-3-B231&origin=search

The U.S. Army Research Laboratory has continued to develop and enhance a millimeter-wave (MMW) and submillimeter-wave (SMMW)/terahertz (THz)-band imaging system performance prediction and analysis tool for both the detection and identification of concealed weaponry and for pilotage obstacle avoidance. The details of the MATLAB-based model that accounts for the effects of all critical sensor and display components, for the effects of atmospheric attenuation, concealment material attenuation, active illumination, target and background orientation, target and background thermal emission, and various imaging system architectures have been reported on in 2005, 2007, and 2011. This paper provides a comprehensive review of a newly enhanced MMW and SMMW/THz imaging system analysis and design tool that now includes an improved noise submodel for more accurate and reliable performance predictions, the capability to account for postcapture image contrast enhancement, and the capability to account for concealment material backscatter with active-illumination-based systems. Present plans for additional expansion of the model’s predictive capabilities are also outlined.

© 2017 Optical Society of America

Abstract-Improved Sensitivity MEMS Cantilever Sensor for Terahertz Photoacoustic Spectroscopy

Ronald A. Coutu 1,* ,  Ivan R. Medvedev 2

 and   Douglas T. Petkie 2

1 Department of Electrical and Computer Engineering, Air Force Institute of Technology, 2950 Hobson Way, Wright-Patterson AFB, Dayton, OH 45433, USA2 Department of Physics, Wright State University, 3640 Colonel Glenn Highway, Dayton, OH 45435, USA

http://www.mdpi.com/1424-8220/16/2/251

In this paper, a microelectromechanical system (MEMS) cantilever sensor was designed, modeled and fabricated to measure the terahertz (THz) radiation induced photoacoustic (PA) response of gases under low vacuum conditions. This work vastly improves cantilever sensitivity over previous efforts, by reducing internal beam stresses, minimizing out of plane beam curvature and optimizing beam damping. In addition, fabrication yield was improved by approximately 50% by filleting the cantilever’s anchor and free end to help reduce high stress areas that occurred during device fabrication and processing. All of the cantilever sensors were fabricated using silicon-on-insulator (SOI) wafers and tested in a custom built, low-volume, vacuum chamber. The resulting cantilever sensors exhibited improved signal to noise ratios, sensitivities and normalized noise equivalent absorption (NNEA) coefficients of approximately 4.28 × 10−10 cm−1·WHz−1/2. This reported NNEA represents approximately a