scholarly journals Switchable DBR Filters Using Semiconductor Distributed Doped Areas (ScDDAs)

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2021
Author(s):  
Rozenn Allanic ◽  
Denis Le Berre ◽  
Cédric Quendo ◽  
David Chouteau ◽  
Virginie Grimal ◽  
...  
Keyword(s):  
High Frequency ◽  
Degrees Of Freedom ◽  
State Of The Art ◽  
Active Surface ◽  
The State ◽  
Semiconductor Substrate ◽  
Great Flexibility ◽  
Active Elements ◽  
Insertion Losses ◽  
Good Agreement

This paper presents a novel way to switch dual-behavior resonator (DBR) filters without any additional active surface-mount components. By using a semiconductor substrate, we were able to simultaneously co-design the filters and semiconductor distributed doped areas (ScDDAs) with integrated N+PP+ junctions as active elements. These ScDDAs act as electrical vias in the substrate, which makes it possible to have an open-circuited resonator in the OFF state and a short-circuited resonator in the ON state, and, consequently, to control the transmission zeroes of the filters. This method offers degrees of freedom as the dimensions and positions of these doped areas can be chosen to obtain the best performances. In this study, four filters were simulated and fabricated to spotlight different possibilities for the dimensions and positions of the ScDDA to control the low- or high-frequency transmission zero of the filters. The simulations were in very good agreement with the measured results. All the filters present insertion losses lower than 2 dB in the OFF and ON states, a great flexibility in the frequency choice, and good agility compared with the state of the art.

scholarly journals DEVELOPMENT OF 3D PIN-BY-PIN CORE SOLVER TORTIN AND COUPLING WITH THERMAL-HYDRAULICS

2021 ◽  
Vol 247 ◽  
pp. 02034
Author(s):  
P. Mala ◽  
A. Pautz ◽  
H. Ferroukhi ◽  
A. Vasiliev
Keyword(s):  
Monte Carlo ◽  
State Of The Art ◽  
The State ◽  
Monte Carlo Code ◽  
Channel Code ◽  
Thermal Hydraulics ◽  
Fuel Temperature ◽  
Power Profile ◽  
Assembly Problem ◽  
Good Agreement

Currently, safety analyses mostly rely on codes which solve both the neutronics and the thermal-hydraulics with assembly-wise nodes resolution as multiphysics heterogeneous transport solvers are still too time and memory expensive. The pin-by-pin homogenized codes can be seen as a bridge between the heterogeneous codes and the traditional nodal assembly-wise calculations. In this work, the pin-by-pin simplified transport solver Tortin has been coupled with a sub-channel code COBRA-TF. The verification of the 3D solver of Tortin is presented at first, showing very good agreement in terms of axial and radial power profile with the Monte Carlo code SERPENT for a small minicore and with the state-of-the-art nodal code SIMULATE5 for a quarter core without feedback. Then the results of Tortin+COBRA-TF are compared with SIMULATE5 for one assembly problem with feedback. The axial profiles of power and moderator temperature show good agreement, while the fuel temperature differ by up to 40 K. This is caused mainly by different gap and fuel conductance parameters used in COBRA-TF and in SIMULATE5.

A Novel Strategy for the Identification of Radiation Force Models

2014 ◽  
Author(s):  
Roman M. Janssen ◽  
Henk Jansen ◽  
Jan-Willem van Wingerden
Keyword(s):  
Asymptotic Behavior ◽  
Frequency Domain ◽  
High Frequency ◽  
State Of The Art ◽  
Radiation Force ◽  
The State ◽  
Test Cases ◽  
Subspace Identification ◽  
Domain Identification

A novel frequency domain identification (FDI) strategy for the identification of radiation force models from frequency domain hydrodynamic data is proposed. First, a subspace identification method is augmented with a convex constraint that guarantees a stable solution. Then, in a second convex optimization problem, constraints on low- and high frequency asymptotic behavior and passivity are enforced. This novel method, constrained frequency domain subspace identification (CFDSI), is validated by comparing both SISO and MIMO CFDSI results with the state-of-the-art FDI toolbox, which is part of the Marine Systems Simulator MATLAB toolbox. In two test cases, it is shown that the novel algorithm can successfully identify a model with either a SISO or MIMO structure, where stability, passivity and the desired low- and high-frequency asymptotic behavior are guaranteed. For the two test cases presented, the quality of the CFDSI models matches the quality of the state-of-the-art FDI models.

scholarly journals Half-Elliptical Resonator Lowpass Filter with a Wide Stopband for Low Band 5G Communication Systems

Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 2916
Author(s):  
Rasoul Azadi ◽  
Saeed Roshani ◽  
Arez Nosratpour ◽  
Ali Lalbakhsh ◽  
Mohammad Hazhir Mozaffari
Keyword(s):  
Transfer Function ◽  
Loss Tangent ◽  
Communication Systems ◽  
Figure Of Merit ◽  
State Of The Art ◽  
The State ◽  
Lowpass Filter ◽  
Transmission Zero ◽  
Transmission Zeros ◽  
Good Agreement

In this paper, a lowpass filter is designed using half elliptical resonators with a wide stopband. New formulas are presented to achieve a circuit model for the half elliptical resonators used in this work. Additionally, the transfer function and transmission zero equations are used to adjust the frequency of the transmission zeros of the filter. The cut-off frequency of the lowpass filter is 1.26 GHz with a sufficiently large stopband, extending from 1.48 GHz to 20 GHz. The proposed filter’s figure of merit is 62,520, demonstrating its outperformance compared to the state of the art. The filter is implemented on a RT-5880 substrate with a constant dielectric of 2.2, thickness of 31 mil and loss tangent of 0.0009. The LPF was fabricated and tested, showing good agreement between the simulated and measured results.

Application of ultra‐precise GRACE Follow-On LRI measurements for validation of the state-of-the-art static gravity field models and examination of sub-monthly time-variable gravity signals

2020 ◽  
Author(s):  
Khosro Ghobadi Far ◽  
Shin-Chan Han ◽  
Jeanne Sauber ◽  
Richard Ray ◽  
Christopher M. McCullough ◽  
...  
Keyword(s):  
Gravity Field ◽  
High Frequency ◽  
State Of The Art ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
The State ◽  
Gravity Change ◽  
Gravity Field Model ◽  
Gravity Field Models

<p>The test Laser ranging interferometer (LRI) on the GRACE Follow-On satellites provides complementary inter-satellite ranging measurements to the baseline K-band microwave ranging (KBR) system that can be used to examine standard, and create novel, GRACE-FO data products.  We first calculated the KBR and LRI inter-satellite ranging residuals using dynamic orbits computed from non-gravitational accelerations, a static gravity field model and other background geophysical models like ocean tides. To accurately quantify the improvement by LRI, we directly examined the inter-satellite ranging residuals in the time and frequency domains. The frequency-domain analysis reveals that LRI enhances the accuracy of gravity measurements by ~1 order of magnitude over 60-200 CPR (10-37 mHz) frequencies with the signal dominated by static gravity field of the Earth. The time-domain analysis shows that LRI is capable of detecting static gravity signals as small as a few 0.1 nm/s<sup>2</sup> in 100-200 CPR frequency band. We made use of such LRI data acquired in 2019 to validate the state-of-the-art gravity field models GGM05S, GGM05C, GOCE-TIM-R6e, EIGEN-6C4, ITSG-Grace2018s and GOCO06s. We found that LRI data can identify subtle un-/mis-modeled static gravity signals in these models in the spectral as well as spatial domains, and thus, suggest how the next generation of gravity field models could be improved. We also examined the high‐frequency (sub-monthly) variations of the Argentine Gyre using LRI measurements along with satellite altimetry data. Through comparison of measured gravity change by LRI with synthetic gravity change from altimetry sea surface data (evaluated at GRACE Follow-On altitude), we clearly demonstrate how the high-frequency Argentine Gyre signal is fully captured by instantaneous LRI measurements by individual data arcs, but not in the monthly mean Level-2 data. Such along-orbit analyses of LRI data could be employed for, among others, validation of high-frequency non-tidal ocean models used in GRACE and GRACE Follow-On de-aliasing products.</p> <p> </p>

High-Frequency Radomes for Polar Region Ground Stations: The State of the Art and Novel Developments of Radome Technologies

2017 ◽  
Vol 59 (6) ◽  
pp. 88-101 ◽  
Author(s):  
Andrea Martellosio ◽  
Marco Pasian ◽  
Luca Perregrini ◽  
Luca Piffer ◽  
Roberto Riccardi ◽  
...  
Keyword(s):  
High Frequency ◽  
Polar Region ◽  
State Of The Art ◽  
The State

On the Maximization of Joint Velocities and Generalized Reactions in the Workspace and Singularity Analysis of Parallel Mechanisms

Robotica ◽  
2018 ◽  
Vol 37 (4) ◽  
pp. 675-690 ◽  
Author(s):  
Pavel Laryushkin ◽  
Victor Glazunov ◽  
Ksenia Erastova
Keyword(s):  
Case Studies ◽  
External Load ◽  
Parallel Mechanism ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
State Of The Art ◽  
Singularity Analysis ◽  
The State ◽  
Parallel Mechanisms ◽  
Different Types

SummaryAn approach for calculating the maximum possible absolute values of joint velocities or generalized reactions in a leg of a parallel mechanism has been considered in this paper. The Jacobian analysis and the Screw theory-based methods have been used to acquire the result. These values are calculated for the “worst” directions of the external load or end-effector’s velocity for each leg. The feasibility of using these parameters as the measures of closeness to different types of parallel mechanism singularity is discussed. Further, how this approach is related to the state-of-the-art methods has been illustrated. The key aspect of the discussed approach is that the normalization of vectors or screws is carried out separately for angular and linear components. One possible advantage of such an approach is that it deals only with the kinematic and statics of the mechanism while still providing physically meaningful and practically applicable measures. Case studies of a 3-Degrees Of Freedom translational parallel mechanism and a planar parallel mechanism are presented for illustration and comparison.

Practical Picture Processing

1974 ◽  
Vol 32 ◽  
pp. 338-339
Author(s):  
T. A. Welton
Keyword(s):  
Radiation Damage ◽  
Coherence Length ◽  
Spatial Information ◽  
State Of The Art ◽  
Coherent Radiation ◽  
The State ◽  
Energy Spread ◽  
Electron Micrograph ◽  
Picture Processing ◽  
Molecular Skeleton

Various authors have emphasized the spatial information resident in an electron micrograph taken with adequately coherent radiation. In view of the completion of at least one such instrument, this opportunity is taken to summarize the state of the art of processing such micrographs. We use the usual symbols for the aberration coefficients, and supplement these with £ and 6 for the transverse coherence length and the fractional energy spread respectively. He also assume a weak, biologically interesting sample, with principal interest lying in the molecular skeleton remaining after obvious hydrogen loss and other radiation damage has occurred.

Hypothesis-Evidence Coordination: The State of the Art

2003 ◽  
Vol 48 (6) ◽  
pp. 826-829 ◽  
Author(s):  
Eric Amsel
Keyword(s):  
State Of The Art ◽  
The State
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