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Full-Text Articles in Engineering
Organic-Based Microwave Frequency Absorbers Using Corn Stover, Ben Smythe, Sean Casserly, Dean Arakaki
Organic-Based Microwave Frequency Absorbers Using Corn Stover, Ben Smythe, Sean Casserly, Dean Arakaki
Electrical Engineering
Commercial antenna test chambers (anechoic) currently use polyurethane foam absorbers on chamber interiors to eliminate undesired radio-frequency (RF) reflections. While effectively absorbing microwave signals, polyurethane material particulates over time adding contaminants to clean rooms and reducing absorber lifetime. These absorbers also release toxic gas when operating under high temperatures and pose a health risk to direct-contact personnel. This paper presents reflectivity analysis and performance of alternative organic-based (corn stover) microwave frequency absorbers for use in anechoic chambers. These absorbers are composed of renewable materials and eliminate the toxic gas release problem for polyurethane materials under high power test conditions. Preliminary …
Multi-Technique Broadband Microstrip Patch Antenna Design, Daniel Colles, Dean Arakaki
Multi-Technique Broadband Microstrip Patch Antenna Design, Daniel Colles, Dean Arakaki
Electrical Engineering
Microstrip patch antennas offer low profile and small footprint advantages, but limited operating bandwidth. Substantial research focuses on broadband techniques. This paper presents the design, simulation, fabrication, and characterization of a 30% bandwidth microstrip patch antenna that incorporates multiple broadband techniques while minimizing footprint area. Methods include patch shape, dielectric thickness, and coupling slot optimization, with capacitively-coupled L-probe feeds. The final design incorporates an electrically thick dielectric and circular-E patch geometry. Microstrip L-probe feed and coupling slot dimensions were optimized via HFSS simulations. The final design was fabricated, and then tested in an anechoic chamber. The new design has measured …
Analytical Parametric Model Used To Study The Influence Of Electrostatic Force On Surface Coverage During Electrospinning Of Polymer Fibers, Joshua Beisel, Jerry Kyeremateng, Lance Purkett, Jessica Andriolo, Jack L. Skinner
Analytical Parametric Model Used To Study The Influence Of Electrostatic Force On Surface Coverage During Electrospinning Of Polymer Fibers, Joshua Beisel, Jerry Kyeremateng, Lance Purkett, Jessica Andriolo, Jack L. Skinner
Electrical Engineering
Electrospinning (ES) can readily produce polymer fibers with cross-sectional dimensions ranging from tens of nanometers to tens of microns. Qualitative estimates of surface area coverage are rather intuitive. However, quantitative analytical and numerical methods for predicting surface coverage during ES have not been covered in sufficient depth to be applied in the design of novel materials, surfaces, and devices from ES fibers. This article presents a modeling approach to ES surface coverage where an analytical model is derived for use in quantitative prediction of surface coverage of ES fibers. The analytical model is used to predict the diameter of circular …