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

Andrea Martellosio; Marco Pasian; Luca Perregrini; Luca Piffer; Roberto Riccardi; Filippo Concaro; Piermario Besso

doi:10.1109/map.2017.2752694

Switchable DBR Filters Using Semiconductor Distributed Doped Areas (ScDDAs)

Electronics ◽

10.3390/electronics9122021 ◽

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.

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A Novel Strategy for the Identification of Radiation Force Models

Volume 1A: Offshore Technology ◽

10.1115/omae2014-23504 ◽

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.

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The state of the art advanced developments of series-resonant high-frequency inverter using static induction transistors/power modules

Conference Record of the 1990 IEEE Industry Applications Society Annual Meeting ◽

10.1109/ias.1990.152467 ◽

2002 ◽

Author(s):

H. Ogiwara ◽

S. Nagai ◽

M. Nakaoka ◽

S. Hamada

Keyword(s):

High Frequency ◽

State Of The Art ◽

The State ◽

Static Induction Transistors ◽

Power Modules ◽

Series Resonant ◽

Static Induction ◽

Frequency Inverter

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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

10.5194/gstm2020-41 ◽

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

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. &#160;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/s2 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&#8208;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. &#160;

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Practical Picture Processing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100051700 ◽

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.

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