- 标题
- 摘要
- 关键词
- 实验方案
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Application of Airborne Infrared Remote Sensing to the Study of Ocean Submesoscale Eddies
摘要： This paper explores the use of infrared remote sensing methods to examine submesoscale eddies that recur downstream of a deep-water island (Santa Catalina, CA). Data were collected using a mid-wave infrared camera deployed on an aircraft flown at an altitude of 3.7 km, and research boats made nearly simultaneous measurements of temperature and current profiles. Structure within the thermal field is generally adequate as a tracer of surface fluid motions, though the imagery needs to be processed in a novel way to preserve the smallest-scale tracer patterns. In the case we focus on, the eddy is found to have a thermal signature of about 1 km in diameter and a cyclonic swirling flow. Vorticity is concentrated over a smaller area of about 0.5 km in diameter. The Rossby number is 27, indicating the importance of the centrifugal force in the dynamical balance of the eddy. By approximating the eddy as a Rankine vortex, an estimate of upward doming of the thermocline (about 14 m at the center) is obtained that agrees qualitatively with the in-water measurements. Analysis also shows an outward radial flow that creates areas of convergence (sinking flow) along the perimeter of the eddy. The imagery also reveals areas of localized vertical mixing within the eddy thermal perimeter, and an area of external azimuthal banding that likely arises from flow instability.
关键词： infrared imagery,surface current,remote sensing of environment,submesoscale eddies,kinematics and dynamics
更新于2025-09-23 15:22:29
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Ti/Au/Al/Ni/Au low contact resistance and sharp edge acuity for highly scalable AlGaN/GaN HEMTs
摘要： In this letter, we have reported a novel metal scheme Ti/Au/Al/Ni/Au for ohmic contact on AlGaN/GaN high electron mobility transistors (HEMTs). The reported metal scheme is observed to show minimum metal out-diffusion and sharp edge acuity at high temperature annealing, which facilitates aggressive scaling of source drain separation (LSD). We have demonstrated LSD as low as 300 nm with gate length (Lg) of 100 nm for this metal stack. We observed improvement in ON-Resistance (RON) from 3 ?.mm to 1.25 ?.mm, transconductance (gm) from 276 mS/mm to 365 mS/mm, saturation drain current (IDS,sat) from 906 mA/mm to 1230 mA/mm and unity current gain frequency (fT) from 70 GHz to 93 GHz by scaling LSD from 3 μm to 300 nm. The gate length for all devices were 100 nm.
关键词： Edge acuity,HEMT,smooth surface,current gain cut-off frequency,ohmic contact resistance,GaN
更新于2025-09-23 15:21:01
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Transmission control by asymmetric electromagnetically induced transparency-like metamaterials in transverse electromagnetic waveguide
摘要： We numerically and experimentally present passive and active electromagnetically induced transparency-like metamaterials in a TEM waveguide under normal excitation. Asymmetry of the metamaterial unit cell leads to the splitting of the radiative resonance. Surface current distributions are analyzed to account for each resonance. Moreover, by implementing a varactor diode to one of the gaps of the double-split ring resonator, electromagnetically induced transmission-like band is shifted in frequency and the corresponding bandwidth is modulated. A modulation ratio of 29.5 dB in transmission is experimentally demonstrated by only increasing the bias voltage 4 volts.
关键词： Surface current distributions,Radiative resonance,Electromagnetically induced transparency,Metamaterial,Modulation ratio
更新于2025-09-16 10:30:52
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[IEEE 2019 16th International Conference on Quality in Research (QIR): International Symposium on Electrical and Computer Engineering - Padang, Indonesia (2019.7.22-2019.7.24)] 2019 16th International Conference on Quality in Research (QIR): International Symposium on Electrical and Computer Engineering - Surface Current Analysis of THz Bowtie Antenna-coupled Microbolometer
摘要： Terahertz (THz) frequency band offers several advantages over microwave band such as larger bandwidth and radiation capability for various imaging applications. One of the important components is the THz detector applicable for room temperature use. For the lower THz frequency band, an antenna-coupled microbolometer is considered as the THz wave detector due to its compact structure and easy to fabricate. In this paper, we design and simulate the antenna-coupled microbolometer for 1 THz frequency band. Simulation is conducted by using CST Microwave Studio. A surface current analysis is performed to understand the effect of the increasing resistance of the microbolometer to the power efficiency performance. From the simulation results, the proposed design and analysis method reveals that power efficiency of the microbolometer can be increased by increasing the resistance of the microbolometer.
关键词： microbolometer,Terahertz,surface current
更新于2025-09-11 14:15:04
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Compact Scalable Modeling of Chipless RFID Tag Based on High-Impedance Surface
摘要： This paper proposes a compact model for chipless radio frequency identification (RFID) tag. This compact scalable model consists of capacitors, inductors, and resistors of which their values are directly described by the physical dimension of the chipless tag. Moreover, based on this compact model, radar cross section of chipless RFID tag is predicted, by analyzing polarizability based on surface current distribution in different modes. To validate the proposed model, a 5-bit chipless RFID tag based on high-impedance surface (HIS) is presented, with good agreement among modeled, simulated, and measured results. A wide range of physical parameters have also been validated to show the scalability. This compact scalable model of chipless RFID tag not only simplifies the tag design, but also provides an insight understanding of the HIS structure.
关键词： radar cross section (RCS),high-impedance surface (HIS),equivalent circuit modeling,Chipless radio frequency identification (RFID) tag,surface current distribution
更新于2025-09-10 09:29:36