Unit-Cell Modeling of High-Speed Interconnect with Adjacent Metal-Filled Via Array using FDTD method

2002 ◽  
Author(s):  
Heeseok Lee ◽  
Charlie Park ◽  
Derek Kam ◽  
Joungho Kim
Keyword(s):  
High Speed ◽  
Fdtd Method ◽  
Unit Cell ◽  
Cell Modeling ◽  
Unit Cell Modeling

scholarly journals A hybrid broadband metalens operating at ultraviolet frequencies

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farhan Ali ◽  
Serap Aksu
Keyword(s):  
Dielectric Material ◽  
Berry Phase ◽  
Uv Light ◽  
Fdtd Method ◽  
Numerical Aperture ◽  
Limited Range ◽  
Unit Cell ◽  
Dielectric Constants ◽  
Phase Method ◽  
Frequency Range

AbstractThe investigation on metalenses have been rapidly developing, aiming to bring compact optical devices with superior properties to the market. Realizing miniature optics at the UV frequency range in particular has been challenging as the available transparent materials have limited range of dielectric constants. In this work we introduce a low absorption loss and low refractive index dielectric material magnesium oxide, MgO, as an ideal candidate for metalenses operating at UV frequencies. We theoretically investigate metalens designs capable of efficient focusing over a broad UV frequency range (200–400 nm). The presented metalenses are composed of sub-wavelength MgO nanoblocks, and characterized according to the geometric Pancharatnam–Berry phase method using FDTD method. The presented broadband metalenses can focus the incident UV light on tight focal spots (182 nm) with high numerical aperture ($$\hbox {NA}\approx 0.8$$ NA ≈ 0.8 ). The polarization conversion efficiency of the metalens unit cell and focusing efficiency of the total metalens are calculated to be as high as 94%, the best value reported in UV range so far. In addition, the metalens unit cell can be hybridized to enable lensing at multiple polarization states. The presented highly efficient MgO metalenses can play a vital role in the development of UV nanophotonic systems and could pave the way towards the world of miniaturization.

Investigation of Contact Conditions During Stamping of a Thin Plate

2020 ◽  
Author(s):  
Harshal Y. Shahare ◽  
Rohan Rajput ◽  
Puneet Tandon
Keyword(s):  
Wave Propagation ◽  
Material Properties ◽  
High Speed ◽  
Fdtd Method ◽  
Propagation Model ◽  
Transmitted Wave ◽  
Two Dimensional ◽  
Contact Conditions ◽  
Simulation Based ◽  
Difference Time

Abstract Stamping is one of the most used manufacturing processes, where real-time monitoring is quite difficult due to high speed of the mechanical press, which leads to deterioration of the accuracy of the products In the present work, a method is developed to model elastic waves propagation in solids to measure contact conditions between die and workpiece during stamping. A two-dimensional model is developed that reduces the wave propagation equations to two-dimensional equations. To simulate the wave propagation inside the die-workpiece model, the finite difference time domain (FDTD) method and modified Yee algorithm has been employed. The numerical stability of the wave propagation model is achieved through courant stability condition, i.e., Courant-Friedrichs-Lewy (CFL) number. Two cases, i.e., flat die-workpiece interface and inclined die-workpiece interface, are investigated in the present work. The elastic wave propagation is simulated with a two-dimension (2D) model of the die and workpiece using reflecting boundary conditions for different material properties. The experimental and simulation-based results of reflected and transmitted wave characteristics are compared for different materials in terms of reflected and transmitted wave height ratio and material properties such as acoustic impedance. It is found that the numerical simulation results are in good agreement with the experimental results.

Thermally Induced Oscillatory Two-Phase Flow in a Mini-Channel: Towards Understanding Pulsating Heat Pipes

2011 ◽  
Author(s):  
Shyama Prasad Das ◽  
Fre´de´ric Lefe`vre ◽  
Sameer Khandekar ◽  
Jocelyn Bonjour
Keyword(s):  
High Speed ◽  
Capillary Tube ◽  
Numerical Models ◽  
Heat Pipes ◽  
Unit Cell ◽  
Operating Pressure ◽  
Operating Characteristics ◽  
Interfacial Instabilities ◽  
Thermally Driven ◽  
Flow Oscillations

Research on Pulsating Heat Pipes (PHP) has received substantial attention in the recent past, due to its unique operating characteristics and potential applications in many passive heat transport situations. Reliable design tools can only be formulated if the nuances of its operating principles are well understood; at present, this is rather insufficient for framing comprehensive models. In this context, this paper reports experimental data on self-sustained thermally driven oscillations in a 2.0 mm ID capillary tube sub-system, consisting of only one vapor slug and one liquid plug (‘unit-cell’). Understanding such a sub-system/‘unit-cell’ is vital, as it represents a primary unit of a multi-turn PHP. Experiments have been performed with two fluids, i.e. Pentane (BP = 36.1°C) and Methanol (BP = 64.7°C) at different evaporator (40°C to 65°C) and condenser temperatures (−5°C to 15°C) respectively. High speed videography and spectrum analysis reveals that self-sustained thermally driven flow oscillations are observed for both fluids, albeit the dominant periodicity is different. Oscillation frequencies vary from 1.5 Hz to 4.2 Hz approximately, depending on the fluid, operating pressure and temperature. Increasing the difference of temperature between the evaporator and condenser sections leads to enhanced driving force for creating flow oscillations. The resulting phase velocities cause interfacial instabilities, resulting in the formation of secondary bubbles which break-off from the main meniscus. Results of this study can be compared to numerical models and will be useful to understand the physics of multi-turn PHPs.

Study on the Characteristics of High Speed near Field Communication Antenna Based on FDTD

2014 ◽  
Vol 1044-1045 ◽  
pp. 1362-1365
Author(s):  
Yan Feng Liu ◽  
Bing Wei
Keyword(s):  
Numerical Simulation ◽  
Field Distribution ◽  
Electric Dipole ◽  
High Speed ◽  
Near Field ◽  
Fdtd Method ◽  
Near Field Communication ◽  
Calculation Results ◽  
The Ideal

The near-field characteristics of the ideal electric dipole are analyzed in this paper. A practical ultrafast band antenna near field FDTD is made and the near field distribution of the antenna is studied by numerical simulation. The calculation results show that the FDTD method is used for the analysis of feasibility and reliability of the near-field communication antenna.

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