239 results on '"E. Longhi"'
Search Results
2. A C-Band MMIC Multi-Functional Core Chip with 7 Bits Phase Shifter and Attenuator Using GaAs pHEMT.
- Author
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Swati Sharma, Shikha Swaroop Sharma, Patrick E. Longhi, Sergio Colangeli, Walter Ciccognani, and Ernesto Limiti
- Published
- 2024
- Full Text
- View/download PDF
3. Partitioned Ohtomo Stability Test for Efficient Analysis of Large-Signal Solutions
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Sergio Colangeli, Leonardo Pantoli, Walter Ciccognani, Patrick E. Longhi, Giorgio Leuzzi, and Ernesto Limiti
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Harmonic balance ,microwaves ,nonlinear circuits ,ohtomo test ,stability analysis ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
A fundamental step in the design of electronic circuits is the verification that they are stable at least on a given set of external terminations, in order to avoid that the solution found be not observable in practice. This is especially true at microwave and millimeter-wave circuits, which are typically analyzed in the frequency domain rather than in the time domain. As a consequence, both in the linear and large-signal case, unstable solutions may be found instead of an observable one. Unfortunately, as compared to the linear case, the stability analysis of large-signal solutions is significantly more cumbersome. In particular, although it is possible to translate the small-signal tests based on the Nyquist principle to large-signal equivalents, the price to pay is a significant increase in matrix size. In the case of the Ohtomo test, which has only recently been applied to large-signal solutions, it is however possible to exploit the structure of the problem to significantly reduce the complexity and, therefore, simulation time. A real-world balanced amplifier is selected to validate the proposed method and illustrate its practical usage. The application of the method to a realistic monolithic circuit with a large number of devices is also presented.
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- 2024
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- View/download PDF
4. Design for Manufacturing of Electro-Mechanical Assemblies in the Aerospace Industry
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Limiti, Ernesto, primary and E. Longhi, Patrick, additional
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- 2020
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5. UWB Circuits and Sub-Systems for Aerospace, Defence and Security Applications
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Limiti, Ernesto, primary and E. Longhi, Patrick, additional
- Published
- 2020
- Full Text
- View/download PDF
6. DC Power-Optimized Ka-Band GaN-on-Si Low-Noise Amplifier With 1.5 dB Noise Figure
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L. Pace, P. E. Longhi, W. Ciccognani, S. Colangeli, F. Vitulli, F. Deborgies, and E. Limiti
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Ka-band ,low-noise amplifier ,Settore ING-INF/01 ,Gallium nitride ,robustness ,Electrical and Electronic Engineering ,Condensed Matter Physics ,satellite applications - Published
- 2022
7. Novel Design Charts for Optimum Source Degeneration Tradeoff in Conjugately Matched Multistage Low-Noise Amplifiers
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Patrick E. Longhi, Ernesto Limiti, Walter Ciccognani, Sergio Colangeli, and Lorenzo Pace
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Noise measurement ,Loss measurement ,Computer science ,Design flow ,Settore ING-INF/01 ,Impedance matching ,low-noise amplifiers (LNAs) ,02 engineering and technology ,monolithic microwave integrated circuits (MMICs) ,Transistors ,Inductor ,Microwave theory and techniques ,high electron mobility transistors (HEMTs) ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Electrical and Electronic Engineering ,Monolithic microwave integrated circuit ,Microwave circuits ,Microwave transistors ,Feedback amplifiers ,Radiation ,Amplifier ,Bandwidth (signal processing) ,020206 networking & telecommunications ,Condensed Matter Physics ,Return loss - Abstract
Source degenerative feedback is extensively applied in the low-noise amplifier design. The beneficial effects of this technique are well established in the open literature. However, the designer is often left to trial-and-error or optimization procedures to identify the adequate amount of feedback when other linear requirements, such as signal matching, come into play. This issue is even more relevant in multistage designs. In this article, we present a synthesis procedure and the relevant design chart to identify the optimum feedback inductor value on all transistors of an $N$ -stage amplifier to obtain a perfect match at its external ports in conjunction with amplifier noise figure minimization and a specified gain requirement. It is shown that the method is applicable to arbitrary $N$ values although it becomes more elaborate for $N$ greater than 6. The method is deterministic as opposed to optimization or trial-and-error-based procedures. The design flow is illustrated at first through a four-stage design with ideal matching elements and subsequently validated by an monolithic microwave integrated circuit (MMIC) test vehicle designed and realized in the WIN foundry’s Gallium Arsenide PIH1-10 process. The measured performance of the test vehicle is NF = 1.9 dB, 26 dB gain, typical I/O return loss of 15 dB in the 26.5–29.5-GHz bandwidth, and practically ideal behavior at the design frequency of 28 GHz.
- Published
- 2021
8. Comparative Evaluation of Optimum Power and Efficiency Terminations Predicted by Alternative Methods for GaN Ka-band Power Amplifier Design
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Ferdinando Costanzo, Patrick E. Longhi, Mikko Kantanen, Rocco Giofre, Walter Ciccognani, Sergio Colangeli, Roberto Quaglia, Mikko Varonen, Paul Tasker, and Ernesto Limiti
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Ka-band ,Gallium Nitride ,MMIC ,Power Amplifiers ,Settore ING-INF/01 - Abstract
A comparative evaluation is provided in this paper regarding two design approaches for Ka-band Gallium Nitride Power Amplifiers. The first approach uses the standard electrical models provided by the foundry, while the alternative approach uses a custom model derived from in-house load-pull characterization. Both Power Amplifiers are designed to provide 30 dBm output power and 30% efficiency in the 31 - 35 GHz bandwidth. It is shown that the PA based on the custom model has a better PAE performance by about 4% and higher output power by 0.3 dB.
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- 2022
9. New Proofs of the Two-Port Networks Unconditional Stability Criteria Based on the Rollett K Parameter
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Antonio Serino, Walter Ciccognani, Sergio Colangeli, Patrick E. Longhi, and Ernesto Limiti
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reflection coefficient ,stability factor ,Circuit stability ,Stability criteria ,High frequency ,Hardware and Architecture ,Microwave theory and techniques ,Settore ING-INF/01 ,Microwave circuits ,Indexes ,Electrical and Electronic Engineering ,two-port ,Scattering parameters - Published
- 2022
10. Nondestructive, Self-Contained Extraction Method of Parasitic Resistances in HEMT Devices
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Patrick E. Longhi, Walter Ciccognani, Antonio Serino, Remy Leblanc, Sergio Colangeli, Julien Poulain, Ernesto Limiti, and Lorenzo Pace
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Physics ,high-electron-mobility transistor (HEMT) ,Radiation ,business.industry ,Transistor ,Linear system ,Settore ING-INF/01 ,Extrinsic circuit ,020206 networking & telecommunications ,Biasing ,02 engineering and technology ,High-electron-mobility transistor ,small-signal equivalent circuit (SSEC) ,Condensed Matter Physics ,parasitic resistances ,law.invention ,Overdetermined system ,law ,Logic gate ,Limit (music) ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Communication channel - Abstract
This article addresses the classical problem of determining the extrinsic resistances ( $R_{G}$ , $R_{S}$ , and $R_{D}$ ) of field-effect transistors (FETs) and, in particular, of high-electron-mobility transistors (HEMTs). The presented approach relies on small-signal measurements of open-channel transistors, as often proposed both for traditional metal–semiconductor FETs (MESFETs) and HEMTs. Unlike what is common practice with HEMTs, the method proposed here does not oversimplify the model of the active channel. On the contrary, we retrieve from the literature a possible analytical model for the open-channel HEMT and use it to determine the triplet of extrinsic resistances without the need of stressing the gate junction with too high currents. Another result of the approach, valid both for MESFETs and HEMTs, is a deterministic way to remove the contribution of the gate junction from the small-signal parameters of the measured devices. All extractions process data that are available on suitable ranges in frequency or in bias voltage, without taking to the limit the sweep parameters or seeking specific resonances. Also, optimizations are only allowed to refine the nominal values, not as the main technique of extraction. These goals are achieved by setting up different subproblems in the form of overdetermined linear systems and then solving by pseudoinversion. The validity of the approach is demonstrated on the measurements of devices from advanced HEMT technologies realized by OMMIC, both GaAs-based (40-nm gate length) and GaN-based (100 and 60 nm).
- Published
- 2020
11. V-Band GaAs Metamorphic Low-Noise Amplifier Design Technique for Sharp Gain Roll-Off at Lower Frequencies
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Sergio Colangeli, Walter Ciccognani, Remy Leblanc, Patrick E. Longhi, Lorenzo Pace, and Ernesto Limiti
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Materials science ,Noise measurement ,Roll-off ,business.industry ,Amplifier ,Settore ING-INF/01 ,indium gallium arsenide ,020206 networking & telecommunications ,Topology (electrical circuits) ,02 engineering and technology ,millimeter-wave integrated circuits ,Condensed Matter Physics ,Noise figure ,Low-noise amplifier ,Gallium arsenide ,chemistry.chemical_compound ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Electrical and Electronic Engineering ,low-noise amplifiers ,business ,V band - Abstract
In this letter, we present the design of a V- band low-noise amplifier for intersatellite crosslink receivers. The test vehicle, realized on industrial metamorphic gallium arsenide technology, operates from 57 to 66 GHz exhibiting 23-dB gain and an average 1.8-dB noise figure. Particular attention was devoted to the analysis and synthesis of an alternative bias injection topology to obtain a sharp gain roll-off at lower frequencies, thus avoiding the insertion, at system level, of an image-reject filter.
- Published
- 2020
12. Kidney transplant tolerance associated with remote autologous mesenchymal stromal cell administration
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Martino Introna, E. Longhi, Eliana Gotti, Norberto Perico, Valentina Portalupi, Federica Casiraghi, Giuseppe Remuzzi, Marta Todeschini, Alessandro Villa, Anna Rita Plati, Marilena Mister, Monica Cortinovis, and Flavio Gaspari
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0301 basic medicine ,Adult ,Male ,Stromal cell ,immunoregulation ,kidney transplantation ,Mesenchymal Stem Cell Transplantation ,Kidney transplant ,Immune tolerance ,03 medical and health sciences ,0302 clinical medicine ,Immune system ,Human Clinical Article ,Medicine ,Humans ,Transplantation, Homologous ,lcsh:QH573-671 ,Kidney transplantation ,Kidney ,lcsh:R5-920 ,tolerance ,business.industry ,lcsh:Cytology ,Mesenchymal stem cell ,Mesenchymal Stem Cells ,Cell Biology ,General Medicine ,medicine.disease ,Autologous bone ,030104 developmental biology ,medicine.anatomical_structure ,immunosuppression withdrawal ,Cancer research ,Transplantation Tolerance ,business ,mesenchymal stromal cells ,lcsh:Medicine (General) ,030217 neurology & neurosurgery ,Developmental Biology - Abstract
Here we report the case of successful immune tolerance induction in a living‐donor kidney transplant recipient remotely treated with autologous bone marrow‐derived mesenchymal stromal cells (MSC). This case report, which to the best of our knowledge is the first in the world in this setting, provides evidence that the modulation of the host immune system with MSC can enable the safe withdrawal of maintenance immunosuppressive drugs while preserving optimal long‐term kidney allograft function., This report provides the evidence that autologous BM‐MSC infusion induces a pro‐tolerogenic immune environment, thus allowing complete discontinuation of antirejection drugs in kidney transplantation
- Published
- 2020
13. A Bound on the Scattering Parameters of Unconditionally Stable N-Ports
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Sergio Colangeli, Walter Ciccognani, Antonio Serino, Patrick E. Longhi, and Ernesto Limiti
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parameter bound ,Scattering ,Circuit stability ,Stability criteria ,Asymptotic stability ,Linear networks ,necessary condition ,Settore ING-INF/01 ,unconditional stability ,Electrical and Electronic Engineering ,Reflectivity ,Terminology ,Scattering parameters - Published
- 2022
14. Ultralow-power digital control and signal conditioning in GaAs MMIC core chip for X-band AESA systems
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Abbas Nasri, Chiara Ramella, Lorenzo Pace, Walter Ciccognani, Marco Pirola, Patrick E. Longhi, and Ernesto Limiti
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Computer science ,Settore ING-INF/01 ,Integrated circuit ,law.invention ,Transmission line measurements ,Gallium arsenide ,law ,Radio frequency ,Electronic engineering ,Insertion loss ,Gallium arsenide (GaAs) ,Digital control ,mixed analog-to-digital integrated circuits ,Electrical and Electronic Engineering ,Monolithic microwave integrated circuit ,Gallium arsenide (GaAs), microwave monolithic integrated circuit (MMIC), mixed analog-to-digital integrated circuits ,Attenuator (electronics) ,Digital electronics ,Integrated circuit reliability ,Load modeling ,Radiation ,business.industry ,Condensed Matter Physics ,Chip ,Integrated circuit modeling ,microwave monolithic integrated circuit (MMIC) ,Microwave circuits ,business ,Phase shift module - Abstract
This work presents the design and characterization of an ultralow-power core chip for electronically scanned arrays at X-band, implemented in 0.25-/0.5-μm E-/D-mode gallium arsenide (GaAs) pHEMT technology. In particular, design details are given about the two core functional blocks embedded in the microwave monolithic integrated circuit (MMIC): a 12-bit phase and amplitude control circuit and an 18-bit serial-to-parallel (S2P) interface. The S2P interface was designed resorting to a custom symmetric device model, expressly conceived for the time-domain simulations required for digital circuits. Due to the adoption of a differential structure with resistive pull-ups, it achieves a state-of-the-art power consumption of 2.2 mW/bit and nearly 87% yield. The analog circuit includes a 6-bit phase shifter (PS) and a 6-bit attenuator. To mitigate risks, two different PS architectures have been developed and are compared in this work, discussing advantages and drawbacks of the different solutions. Since the two designs share the same target specifications, a truly fair comparison can be made not only in terms of performance but also concerning robustness and repeatability, thus providing useful guidelines for the selection of the most appropriate strategy. In particular, it is shown that one architecture outperforms the other by about 2 dB and 1.5° in terms of insertion loss and rms phase error, respectively.
- Published
- 2022
15. The Stability Radius: A New Indicator of Unconditional Stability for N-Port Linear Networks
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Sergio Colangeli, Walter Ciccognani, Antonio Serino, Patrick E. Longhi, and Ernesto Limiti
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Settore ING-INF/01 ,N-port network ,Electrical and Electronic Engineering ,Condensed Matter Physics ,Small-signal stability ,unconditional stability (US) - Published
- 2022
16. Source/Load-Pull Noise Measurements at Ka Band
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Remy Leblanc, Lorenzo Pace, Sergio Colangeli, Walter Ciccognani, Antonio Serino, Patrick E. Longhi, Ernesto Limiti, and Julien Poulain
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Test bench ,Noise power ,Technology ,Control and Optimization ,Materials science ,Gallium Nitride on Silicon ,Settore ING-INF/01 ,Energy Engineering and Power Technology ,02 engineering and technology ,High-electron-mobility transistor ,Noise figure ,noise characterization ,Optics ,0202 electrical engineering, electronic engineering, information engineering ,Ka band ,Electrical and Electronic Engineering ,Engineering (miscellaneous) ,HEMT ,Renewable Energy, Sustainability and the Environment ,business.industry ,Y-factor technique ,020208 electrical & electronic engineering ,Load pull ,020206 networking & telecommunications ,cold-source technique ,source pull ,black-box modeling ,Device under test ,business ,Noise (radio) ,Energy (miscellaneous) - Abstract
This paper is focused on the extraction of the noise parameters of a linear active device by exploiting both forward and reverse noise power measurements associated with different terminations. In order for load-pull measurements to yield a significant marginal improvement (as compared to forward measurements only) it is expected that the device under test should appreciably deviate from unidirectionality. For this reason, the source/load-pull technique is applied to frequencies at which the considered devices are still usable but their reverse noise factor exhibits a measurable dependence on the output terminations. Details on the test bench set up to the purpose, covering the 20–40 GHz frequency range, are provided. A characterization campaign on a 60 nm gate length, 4×35 µm GaN-on-Si HEMT fabricated by OMMIC is illustrated.
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- 2021
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17. Improved microwave attenuator topology minimizing the number of control voltages
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Ernesto Limiti, Sergio Colangeli, Walter Ciccognani, and Patrick E. Longhi
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Attenuator (electronics) ,Computer science ,020206 networking & telecommunications ,Topology (electrical circuits) ,02 engineering and technology ,Condensed Matter Physics ,Topology ,Settore ING-INF/01 - Elettronica ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Hardware_INTEGRATEDCIRCUITS ,0202 electrical engineering, electronic engineering, information engineering ,Control signal ,Field-effect transistor ,Electrical and Electronic Engineering ,Voltage reference ,Monolithic microwave integrated circuit ,Microwave ,Voltage - Abstract
This letter presents an improved circuit topology to minimize the number of external control voltages that are required to set the state of an N-bit microwave digital attenuator. An alternative method to connect the control signal is proposed. Typically, the control signal is connected to the gate terminal of the field effect transistor while the source terminal is DC grounded. Here, the control signal is applied to the source terminal of the field effect transistor while the gate is connected to a fixed reference voltage. In this way, only one control voltage is necessary to set the state of single attenuator cell vs two control voltages required in the typical case. The proposed method becomes particularly beneficial as the number of bits increases (ie, >4). The topology has been validated through design, realization, and testing of a 5-bit Monolithic Microwave Integrated Circuit (MMIC) attenuator operating over the full C-band (4-8 GHz).
- Published
- 2018
18. Linear Characterization and Modeling of GaN-on-Si HEMT Technologies with 100 nm and 60 nm Gate Lengths
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Lorenzo Pace, Ernesto Limiti, Julien Poulain, Sergio Colangeli, Walter Ciccognani, Remy Leblanc, and Patrick E. Longhi
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Test bench ,Materials science ,Computer Networks and Communications ,Settore ING-INF/01 ,lcsh:TK7800-8360 ,02 engineering and technology ,High-electron-mobility transistor ,Noise figure ,Noise (electronics) ,noise temperatures ,Reduction (complexity) ,0202 electrical engineering, electronic engineering, information engineering ,characterization ,Electrical and Electronic Engineering ,Monolithic microwave integrated circuit ,HEMT ,Cold-source technique ,business.industry ,Y-factor technique ,lcsh:Electronics ,Linear model ,Noise tem-peratures ,020206 networking & telecommunications ,modeling ,021001 nanoscience & nanotechnology ,Hardware and Architecture ,Control and Systems Engineering ,Signal Processing ,gallium nitride on silicon ,scalable SSEC ,Optoelectronics ,0210 nano-technology ,business ,Voltage - Abstract
Motivated by the growing interest towards low-cost, restriction-free MMIC processes suitable for multi-function, possibly space-qualified applications, this contribution reports the extraction of reliable linear models for two advanced GaN-on-Si HEMT technologies, namely OMMIC&rsquo, s D01GH (100 nm gate length) and D006GH (60 nm gate length). This objective is pursued by means of both classical and more novel approaches. In particular, the latter include a nondestructive method for determining the extrinsic resistances and an optimizaion-based approach to extracting the remaining parasitic elements: these support standard DC and RF measurements in order to obtain a scalable, bias-dependent equivalent-circuit model capturing the small-signal behavior of the two processes. As to the noise model, this is extracted by applying the well known noise-temperature approach to noise figure measurements performed in two different frequency ranges: a lower band, where a standard Y-factor test bench is used, and an upper band, where a custom cold-source test bench is set up and described in great detail. At 5 V drain-source voltage, minimum noise figures as low as 1.5 dB and 1.1 dB at 40 GHz have been extracted for the considered 100 nm and 60 nm HEMTs, respectively: this testifies the maturity of both processes and the effectiveness of the gate length reduction. The characterization and modeling campaign, here presented for the first time, has been repeatedly validated by published designs, a couple of which are reviewed for the Reader&rsquo, s convenience.
- Published
- 2021
19. Use of DPB1 T-cell epitope algorithm among italian transplant centers: a survey on behalf of Associazione Italiana di Immunogenetica e Biologia dei Trapianti
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E. Longhi, P Chiusolo, Elena Bevilacqua, Elisabetta Guizzardi, Lia Mele, Valeria Miotti, Angela Rossi, Benedetta Mazzi, Sara Lai, Carlo Carcassi, Valentina Cappuzzo, Manuela Testi, Rita Tognellini, Claudia Lombardo, Graziella Carella, Laura Perotti, D. Mininni, Nadia Ceschini, Roberta Penta, Nesci S, Marina Tagliaferri Cinzia, Pia Azzaro Maria, Mariadele Scollo Chiara, Paola Albergoni Maria, Paola Grammatico, Barbara Murgia, Antonina Piazza, Giuseppe Cappucci, Elena Garino, Roberto Crocchiolo, Laura Castellani, Cinzia Vecchiato, Silvia Giuliodori, Marco Andreani, and Silvia Manfroi
- Subjects
HLA-DPB1 ,business.industry ,donor ,hematopoietic stem cell transplantation ,T-cell epitope algorithm ,Histocompatibility Testing ,Immunology ,Hematopoietic Stem Cell Transplantation ,Epitopes, T-Lymphocyte ,Human leukocyte antigen ,Epitope ,Italy ,Unrelated Donor ,Allogeneic hsct ,Surveys and Questionnaires ,Genetics ,Immunology and Allergy ,Medicine ,Humans ,In patient ,business ,Unrelated Donors ,Algorithm ,Algorithms ,Alleles ,HLA-DP beta-Chains - Abstract
The HLA-DPB1 locus has been demonstrated to have a significant role on patients' outcome after allogeneic HSCT, and the so-called T-cell epitope (TCE) algorithm has been incorporated in international guidelines for the selection of unrelated donors. The purpose of the present study is to measure, through a national survey conducted on behalf of the Associazione Italiana di Immunogenetica e Biologia dei Trapianti (AIBT), the extent of awareness and use of HLA-DPB1 TCE-based algorithms during the donor search. 89% of the HLA laboratories answered to a short questionnaire and the results showed a progressive increase of the laboratories typing DPB1 in patients and their potential donors during the search (from 44% to 79% during the 2010-2019 period) as well as the application of a TCE-based algorithm for the donor choice whenever possible (from 24% to 65% during the same period). The DP-permissiveness status is detailed in the official HLA typing report by 12%, 32% and 50% of laboratories in 2010, 2015 and 2019, respectively. The present data indicate an encouraging raise in the awareness of the HLA-DPB1 role in unrelated donor selection; noteworthy, mentioning the TCE-based permissiveness status in the HLA typing report of each potential unrelated donor represents a notable mean to raise awareness among transplant physicians and to support them in their task of choosing the best donor. Nonetheless, despite the compelling evidence of the predictive ability of TCE-based algorithms, further efforts are still needed to extend its application to all transplant centers in Italy.
- Published
- 2021
20. A MMIC Low-Noise Amplifier realized with two different gate length GaN-on-Si technologies
- Author
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Lorenzo Pace, Walter Ciccognani, Sergio Colangeli, Ernesto Limiti, Patrick E. Longhi, and Remy Leblanc
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Silicon ,Materials science ,Microwave amplifiers ,Noise measurement ,Gain measurement ,business.industry ,Satellites ,020208 electrical & electronic engineering ,Transistor ,Ka-Band ,Gate length ,Settore ING-INF/01 ,020206 networking & telecommunications ,02 engineering and technology ,Low-Noise Amplifier ,Low-noise amplifier ,law.invention ,Gallium Nitride ,law ,Logic gate ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,business ,Monolithic microwave integrated circuit ,MMICs - Abstract
In this work, a Ka-Band MMIC LNA designed with two different gate length GaN-on-Si devices is shown. Measurements show a gain higher than 29dB, 2.1dB average NF in the 34÷37.5GHz design band and a 1dBcp around 23-24dBm in the 35÷36.5GHz target band, showing a good suitability to highgain, low-noise and medium-power requests. Comparison with GaN-on-SiC-based similar works confirms the feasibility of the adoption of GaN-on-Si technology for space-borne applications.
- Published
- 2021
21. Extending the ohtomo stability test to large-signal solutions in a commercial circuit simulator
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Leonardo Pantoli, Patrick E. Longhi, Walter Ciccognani, Sergio Colangeli, Giorgio Leuzzi, and Ernesto Limiti
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Radiation ,Relation (database) ,Computer science ,Amplifier ,Stability (learning theory) ,Settore ING-INF/01 ,Stability analysis ,Context (language use) ,Harmonic balance ,Microwaves ,Nonlinear circuits ,Ohtomo test ,Condensed Matter Physics ,Electronic circuit simulation ,Nonlinear system ,Control theory ,Electrical and Electronic Engineering ,Complex plane ,Electronic circuit - Abstract
The stability analysis of nonlinear circuits is a central problem in the framework of microwave design, as applied to high-power amplifiers, oscillators, frequency dividers, and multipliers. However, reliable, user-friendly tools for the stability analysis of such components seem to be quite scarce, even within the very commercial suites for high-frequency circuit simulation. This contribution addresses the problem by generalizing Ohtomo’s test—a popular tool born in the context of linear circuits—to the nonlinear case. Specifically, the new technique allows to analyze the characteristic zeros of a linearized large-signal solution resulting from a harmonic-balance (HB) simulation. As well known, the location of these zeros with respect to the imaginary axis of the complex plane is critical in relation to the qualitative nature of the solution, i.e., to its stability. To the best of the authors’ knowledge, for the first time, a large-signal stability test based on the system determinant but not requiring direct access to the nonlinear elements is implemented completely within a commercial circuit simulator (i.e., without requiring an external mathematical environment for data postprocessing). Some limitations still present are discussed. The generalized Ohtomo test was validated against other methods and circuits from the literature.
- Published
- 2021
22. Broadband amplifier design technique by dissipative matching networks
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Rocco Giofre, Patrick E. Longhi, Antonio Serino, Ernesto Limiti, Walter Ciccognani, Sergio Colangeli, and Lorenzo Pace
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Lossless compression ,Matching (statistics) ,Computer science ,Flatness (systems theory) ,Amplifier ,Return loss ,Electronic engineering ,Impedance matching ,Settore ING-INF/01 ,Linearity ,Electrical and Electronic Engineering ,Mismatch loss - Abstract
This work is focused on the design of broadband amplifiers by exploiting dissipative reciprocal matching networks. Unlike the classical approach, which makes use of lossless reciprocal matching networks, there is no need to trade-off the gain flatness with the input/output matching levels. In this contribution the flat gain condition is obtained partially by exploiting the mismatch loss at a certain section and partially by leveraging on ohmic losses. In particular, two different matching schemes have been analytically studied. Taking advantage of the more promising scheme of the two presented, the design of a linear power amplifier operating over the 4–40 GHz decade, is illustrated. The amplifier showed measured input/output return loss better than 9/10 dB respectively, a gain of 8 ± 0.6 dB and an output power level of 25.5 ± 0.5 dBm at 1 dB compression point. Incidentally, unconditional stability is obtained without considering additional stabilization networks or components devoted to the purpose.
- Published
- 2021
23. Fluctuations in granular materials
- Author
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R. P. Behringer, Junfei Geng, D. Howell, E. Longhi, G. Reydellet, L. Vanel, E. Clément, and S. Luding
- Published
- 2020
24. S-band hybrid amplifiers based on hydrogenated diamond FETs
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Claudio Verona, Walter Ciccognani, Sergio Colangeli, Patrick E. Longhi, Massimiliano Benetti, Domenico Cannatà, Ernesto Limiti, Gianluca Verona Rinati, Vittorio Camarchia, Fabio Di Pietrantonio, Marco Marinelli, and Marco Pirola
- Subjects
Materials science ,Settore ING-INF/01 ,lcsh:Medicine ,02 engineering and technology ,engineering.material ,Noise figure ,01 natural sciences ,Article ,0103 physical sciences ,Electronic devices ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,lcsh:Science ,010302 applied physics ,Multidisciplinary ,Amplifier ,lcsh:R ,dBm ,Bandwidth (signal processing) ,Diamond ,020206 networking & telecommunications ,Electrical and electronic engineering ,Transducer ,engineering ,lcsh:Q ,S band ,Microwave - Abstract
The first realizations of S-band hybrid amplifiers based on hydrogenated-diamond (H-diamond) FETs are reported. As test vehicles of the adopted H-diamond technology at microwave frequencies, two designs are proposed: one, oriented to low-noise amplification, the other, oriented to high-power operation. The two amplifying stages are so devised as to be cascaded into a two-stage amplifier. The activities performed, from the technological steps to characterization, modelling, design and realization are illustrated. Measured performance demonstrates, for the low-noise stage, a noise figure between 7 and 8 dB in the 2–2.5 GHz bandwidth, associated with a transducer gain between 5 and 8 dB. The OIP3 at 2 GHz is 21 dBm. As to the power-oriented stage, its transducer gain is 5–6 dB in the 2–2.5 GHz bandwidth. The 1-dB output compression point at 2 GHz is 20 dBm whereas the OIP3 is 33 dBm. Cascading the measured S-parameters of the two stages yields a transducer gain of 15 ± 1.2 dB in the 2–3 GHz bandwidth.
- Published
- 2020
25. C to V-band Cascode Distributed Amplifier Design Leveraging a Double Gate Length Gallium Nitride on Silicon Process
- Author
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Lorenzo Pace, Remy Leblanc, Walter Ciccognani, Patrick E. Longhi, Sergio Colangeli, and Ernesto Limiti
- Subjects
Materials science ,Settore ING-INF/01 ,Gallium nitride ,02 engineering and technology ,Substrate (electronics) ,distributed amplifiers, millimeter wave integrated circuits, Gallium Nitride, broadband amplifiers ,law.invention ,chemistry.chemical_compound ,millimeter wave integrated circuits ,law ,0202 electrical engineering, electronic engineering, information engineering ,Silicon carbide ,broadband amplifiers ,business.industry ,Amplifier ,020208 electrical & electronic engineering ,Transistor ,Distributed amplifier ,020206 networking & telecommunications ,Gallium Nitride ,distributed amplifiers ,chemistry ,Optoelectronics ,Cascode ,business ,V band - Abstract
Design solutions and technology considerations of a 6–52 GHz cascode distributed amplifier are presented in this paper. The amplifier is designed in a Gallium Nitride on Silicon process with two different gate length transistors, namely 60 nm and 100 nm, connected in cascode configuration. The test vehicle, whose additional aim is to show the possibility to integrate transistors with different gate lengths onto the same chip, demonstrates 9 dB gain, 28 dBm saturated output power, 20% PAE and 37 dBm IP3, on average. Comparison with Gallium Nitride on Silicon Carbide based similar works reveals satisfactory performance obtained however on a cost effective and high volume production substrate.
- Published
- 2020
26. Design of a Ka-Band Single-Chip Front-End based on a 100 nm GaN-on-Si technology
- Author
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Lorenzo Pace, Remy Leblanc, A. Suriani, Sergio Colangeli, Patrick E. Longhi, Ernesto Limiti, Ferdinando Costanzo, and Walter Ciccognani
- Subjects
Power gain ,Power-added efficiency ,High-Power Amplifier (HPA) ,Materials science ,business.industry ,Core Chip ,020208 electrical & electronic engineering ,Settore ING-INF/01 ,020206 networking & telecommunications ,Switch ,02 engineering and technology ,Gallium Arsenide (GaAs) ,Noise figure ,Chip ,Single-Chip Front-End (SCFE) ,Logic gate ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Low-Noise Amplifier (LNA) ,Ka band ,Radio frequency ,Gallium Nitride (GaN) ,business ,Monolithic microwave integrated circuit - Abstract
In this paper, a Single-Chip Front-End (SCFE) operating in Ka-Band (35–36.5 GHz) is presented. Chip is designed exploiting a GaN-on-Si technology featured by 100nm gate length provided by OMMIC foundry. This MMIC integrates high-power, low-noise amplification functionalities enabled by a couple of synchronous Single-Pole Double-Throw (SPDT) switches, occupying a total surface of 4.7×3 mm2. Transmit-mode (Tx) performance present a 36 dBm output power, a Power Added Efficiency (PAE) higher than 25% and a 20dB power gain at 2 dB compression. Regarding the receiving-mode (Rx) performance, a sub-3.2 dB Noise Figure (NF) and a linear gain just below the 32 dB level is obtained, with a I/O matching better than 20 dB, as well.
- Published
- 2020
27. Design and Validation of 100 nm GaN-On-Si Ka-Band LNA Based on Custom Noise and Small Signal Models
- Author
-
Patrick E. Longhi, Sergio Colangeli, Remy Leblanc, Walter Ciccognani, Lorenzo Pace, M. Feudale, Ernesto Limiti, and Fabio Vitobello
- Subjects
Materials science ,Computer Networks and Communications ,low-noise amplifier (LNA) ,gallium nitride (GaN) ,GaN/Si ,GaN-on-Si ,high linearity ,HEMT ,Ka-band ,Gate length ,lcsh:TK7800-8360 ,02 engineering and technology ,High-electron-mobility transistor ,Noise figure ,01 natural sciences ,Signal ,Noise (electronics) ,Settore ING-INF/01 - Elettronica ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Ka band ,Electrical and Electronic Engineering ,Monolithic microwave integrated circuit ,010302 applied physics ,business.industry ,Amplifier ,lcsh:Electronics ,020206 networking & telecommunications ,Hardware and Architecture ,Control and Systems Engineering ,Signal Processing ,Optoelectronics ,business - Abstract
In this paper a GaN-on-Si MMIC Low-Noise Amplifier (LNA) working in the Ka-band is shown. The chosen technology for the design is a 100 nm gate length HEMT provided by OMMIC foundry. Both small-signal and noise models had been previously extracted by the means of an extensive measurement campaign, and were then employed in the design of the presented LNA. The amplifier presents an average noise figure of 2.4 dB, a 30 dB average gain value, and input/output matching higher than 10 dB in the whole 34&ndash, 37.5 Ghz design band, while non-linear measurements testify a minimum output 1 dB compression point of 23 dBm in the specific 35&ndash, 36.5 GHz target band. This shows the suitability of the chosen technology for low-noise applications.
- Published
- 2020
- Full Text
- View/download PDF
28. Low power GaAs digital and analog functionalities for microwave signal conditioning in AESA systems
- Author
-
Motahhareh Estebsari, Lorenzo Pace, Walter Ciccognani, Ernesto Limiti, Patrick E. Longhi, Marco Pirola, Chiara Ramella, and Abbas Nasri
- Subjects
Attenuators ,Transceivers ,Materials science ,Beam steering ,Settore ING-INF/01 ,02 engineering and technology ,Phase Shifters ,01 natural sciences ,Gallium Arsenide ,Beam Steering ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Signal conditioning ,Monolithic microwave integrated circuit ,010302 applied physics ,business.industry ,Mixed Analog-Digital Integrated Circuits ,Bandwidth (signal processing) ,Electrical engineering ,020206 networking & telecommunications ,Chip ,Radio frequency ,Transceiver ,business ,Microwave - Abstract
A MMIC demonstrator for RF phase and amplitude control with on board 18-bit serial to parallel conversion (Multi-Functional Chip) is presented. Thanks to an alternative digital building block topology, the DC power consumption of the digital serial to parallel converter is noteworthy: less than 43 mW (2 mW/bit). The main RF performances are 0° – 360° phase coverage and 0 dB – 31.5 dB attenuation setting, in the 7.6 GHz – 9.1 GHz operating bandwidth. The circuit, whose area is 6 mm2, is realised in an industrial and commercially available GaAs technology. This component can be used in active electronically scanned arrays for beam steering.
- Published
- 2020
29. A Test for Unconditional Stability Based on Polynomial Convexification
- Author
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Sergio Colangeli, Patrick E. Longhi, Ernesto Limiti, and Walter Ciccognani
- Subjects
Mathematical optimization ,Polynomial ,Radiation ,Current (mathematics) ,small-signal stability ,Computer science ,Stability (learning theory) ,Settore ING-INF/01 ,020206 networking & telecommunications ,Field (mathematics) ,02 engineering and technology ,Condensed Matter Physics ,Convergence (routing) ,Convex optimization ,0202 electrical engineering, electronic engineering, information engineering ,N-port network ,unconditional stability ,Electrical and Electronic Engineering ,Algebraic number ,Numerical stability - Abstract
A theoretical analysis is carried out of the problem of checking the unconditional stability of a linear $N$ -port with arbitrary $N$ , explaining at length its inherent difficulties. To overcome the algebraic roadblock, an optimization-based method is proposed; the main novelty is that notwithstanding the use of optimization, the problem formulation is specifically chosen so as to guarantee convergence to the global minimum. In particular, recent advancements in the field of convex optimization, mostly unknown to the high-frequency engineering community, are exploited to that end. The result is a method suitable for checking the unconditional stability of linear $N$ -ports with $N$ up to 4. Higher numbers of ports, although allowed in principle, are not viable with the current combination of hardware resources and software implementation. Several examples of applications are provided, both purely illustrative and from actual circuit designs.
- Published
- 2020
30. Design for Manufacturing of Electro-Mechanical Assemblies in the Aerospace Industry
- Author
-
Ernesto, Limiti and E., Longhi, Patrick
- Subjects
InformationSystems_INFORMATIONSTORAGEANDRETRIEVAL ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) - Published
- 2019
31. Development of a MMIC chip-set for W-band space-borne communications
- Author
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Patrick E. Longhi, Silvio Fenu, Lorenzo Pace, Ernesto Limiti, and Carlo Antonio Leone
- Subjects
Physics ,Chipset ,business.industry ,Amplifier ,Frequency multiplier ,Local oscillator ,020208 electrical & electronic engineering ,Settore ING-INF/01 ,020206 networking & telecommunications ,Mixers, Topology, Radio frequency, Harmonic analysis, Receivers, Gallium arsenide ,02 engineering and technology ,Noise figure ,Topology ,Receivers ,Mixers ,Harmonic analysis ,Gallium arsenide ,W band ,Radio frequency ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,business ,Monolithic microwave integrated circuit - Abstract
The feasibility of a W-band (81-86 GHz) downconverter for space-borne communications is verified in this paper through the design of a custom MMIC chip-set. The latter is composed of three functionalities: a low-noise amplifier (LNA), a sub-harmonically pumped mixer (SHM), and an active frequency doubler that provides the local oscillator (LO) pump to the mixer. The MMICs have been designed with OMMIC’s 70 nm and UMS’s 100nm GaAs technologies, in order to exploit the best-of-both technologies (low-noise and power-handling at millimetre-wave). The LNA features 23 dB gain and sub-2.5 dB Noise Figure in the whole operating band, while the mixer shows 13 dB conversion loss (CL). Finally, the active doubler provides > +10dBm pump at the necessary LO frequency.
- Published
- 2019
32. Development of a V-Band MMIC chip-set for in-orbit Inter-Satellite Links
- Author
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Silvio Fenu, Walter Ciccognani, Patrick E. Longhi, Sergio Colangeli, Ernesto Limiti, and Lorenzo Pace
- Subjects
Physics ,Chipset ,Frequency band ,business.industry ,Noise measurement ,Amplifier ,020208 electrical & electronic engineering ,Settore ING-INF/01 ,020206 networking & telecommunications ,Port (circuit theory) ,Mixers, Gain, Radio frequency, Gallium arsenide, Noise measurement, Topology ,02 engineering and technology ,Noise figure ,Topology ,Mixers ,Gallium arsenide ,Radio frequency ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Gain ,business ,Monolithic microwave integrated circuit ,V band - Abstract
In this paper, the feasibility of a V-band MMIC chipset is tested by the design of a Low-Noise Amplifier (LNA) operating in the 59-66 GHz frequency band and two Mixers exploiting two different topologies that convert signals from the 60-60.4 GHz band to 8-8.4 GHz band and vice versa. The MMICs have been designed exploiting OMMIC’s 70 nm and 130 nm GaAs technologies. LNA shows a 23 dB gain and a sub-2 dB Noise Figure in the whole operating band, while the two Mixers show a 11-12 dB conversion loss, along with LO isolation towards RF and IF port higher than 22 dB and a simulated Input 1 dB Compression Point of 10 dBm.
- Published
- 2019
33. Q/V band LNA for satellite on-board space applications using a 70 nanometers GaAs mHEMT commercial technology
- Author
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Patrick E. Longhi, Ernesto Limiti, Walter Ciccognani, and Sergio Colangeli
- Subjects
Physics ,business.industry ,020208 electrical & electronic engineering ,020206 networking & telecommunications ,02 engineering and technology ,Condensed Matter Physics ,Space (mathematics) ,Settore ING-INF/01 - Elettronica ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,On board ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Nanometre ,Satellite ,Electrical and Electronic Engineering ,business ,V band - Published
- 2018
34. Design of a GaN-on-Si Single-Balanced Resistive Mixer for Ka -band Satcom
- Author
-
Aurora De Padova, Walter Ciccognani, Patrick E. Longhi, Sergio Colangeli, and Ernesto Limiti
- Subjects
Materials science ,business.industry ,Local oscillator ,020206 networking & telecommunications ,Electrical element ,Gallium nitride ,02 engineering and technology ,Condensed Matter Physics ,chemistry.chemical_compound ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Ka band ,Radio frequency ,Electrical and Electronic Engineering ,Circuit complexity ,business ,Monolithic microwave integrated circuit ,Voltage - Abstract
Design and performance of a gallium nitride (GaN)-on-Si mixer for the Ka -band satellite telecom applications are presented in this letter. GaN-on-Si offers the advantage of high-volume production even for millimeter-wave applications. A single-balanced architecture is selected as an optimum tradeoff between circuit complexity and rejection of local oscillator (LO) harmonics. An alternative circuit topology is adopted where the in-phase combiner and hybrid quadrature couplers, used to obtain the desired signal phasing at mixer output, are also employed as circuit elements to inject external bias voltages so to optimize the mixer’s conversions loss (CL). The mixer features 11-dB CL, 11- and 22-dBm P1dB and IIP3 respectively, in the 26–31-GHz bandwidth when driven by a 10-dBm LO level. Monolithic microwave integrated circuit area is less than 6 mm2.
- Published
- 2019
35. Comparative noise investigation of high-performance GaAs and GaN millimeter-wave monolithic technologies
- Author
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Silvio Fenu, Lorenzo Pace, Ernesto Limiti, Julien Poulain, Sergio Colangeli, Walter Ciccognani, Antonio Serino, Remy Leblanc, and Patrick E. Longhi
- Subjects
Materials science ,business.industry ,Amplifier ,020208 electrical & electronic engineering ,Transistor ,Linearity ,020206 networking & telecommunications ,02 engineering and technology ,Noise figure ,Settore ING-INF/01 - Elettronica ,law.invention ,CMOS ,Robustness (computer science) ,law ,Extremely high frequency ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,business ,Monolithic microwave integrated circuit - Abstract
This paper provides an assessment between two MMIC foundry processes for millimetre-wave high-performance receiver applications, namely, OMMIC’s 70 nm GaAs and 60 nm GaN-on-Si processes. To do so, a characterization and modelling campaign was carried out on transistors provided by OMMIC for the two processes, whose commercial names are D007IH (70 nm GaAs) and D006GH (60 nm GaN). The resulting models were employed to design several test vehicle Low-Noise Amplifiers (LNA) operating above 30 GHz. The GaAs LNAs have been manufactured and characterized, while the GaN-on-Si LNAs are being manufactured. The initial outcome of the assessment is that GaAs is still ahead if Noise Figure is the crucial and mandatory requirement. GaN-on-Si, on the other hand, proves to be a viable solution if a – slightly – higher Noise Figure is acceptable. Moreover, the benefits of GaN-on-Si, with respect to GaAs, are higher robustness, output power, linearity, and higher integration capability with CMOS technologies.
- Published
- 2019
36. UWB Circuits and Sub-Systems for Aerospace, Defence and Security Applications
- Author
-
Ernesto, Limiti and E., Longhi, Patrick
- Subjects
InformationSystems_INFORMATIONSTORAGEANDRETRIEVAL ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) - Published
- 2019
37. A Ka-Band Low-Noise Amplifier for Space Applications in a 100 nm GaN on Si technology
- Author
-
Remy Leblanc, Patrick E. Longhi, Ernesto Limiti, Sergio Colangeli, Walter Ciccognani, and Lorenzo Pace
- Subjects
Materials science ,Low-Noise Amplifier (LNA) ,Gallium Nitride (GaN) ,GaN-on-Si ,high linearity ,HEMT ,Ka-band ,Gallium nitride ,02 engineering and technology ,High-electron-mobility transistor ,Noise figure ,Settore ING-INF/01 - Elettronica ,01 natural sciences ,chemistry.chemical_compound ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Ka band ,Monolithic microwave integrated circuit ,010302 applied physics ,Noise measurement ,business.industry ,Amplifier ,020206 networking & telecommunications ,Low-noise amplifier ,chemistry ,Optoelectronics ,business - Abstract
In this paper a MMIC Low-Noise Amplifier operating in Ka-band is presented. The chosen technology is a 100 nm GaN HEMT on a High Resistivity Silicon substrate. A fully deterministic approach based on constant mismatch circles has been used for the preliminary synthesis of matching networks. The designed four-stages LNA presents a 33 dB gain, Input/Output matching better than 21 dB and a Noise Figure of no more than 2.3 dB in the whole operating band, showing the suitability of the chosen technology to low-noise, high gain and linearity applications.
- Published
- 2019
38. A Times-4 Frequency Multiplier from K- to W-band
- Author
-
P. Frtjlink, Alessandro Salvucci, Silvio Fenu, M. Renvoise, Walter Ciccognani, Patrick E. Longhi, Sergio Colangeli, Ernesto Limiti, and Lorenzo Pace
- Subjects
Physics ,business.industry ,Frequency multiplier ,Harmonic analysis, Frequency modulation, Field effect transistors, Power generation, Power system harmonics, Photonics ,020208 electrical & electronic engineering ,Settore ING-INF/01 ,dBc ,02 engineering and technology ,Field effect transistors ,Signal ,Power (physics) ,Harmonic analysis ,Photonics ,W band ,Frequency modulation ,Power system harmonics ,0202 electrical engineering, electronic engineering, information engineering ,Harmonic ,Optoelectronics ,business ,Monolithic microwave integrated circuit ,Power generation ,Communication channel - Abstract
In this paper, a times four K- to W-Band frequency multiplier involved in the generation of a Local Oscillator signal is presented. The chosen technology for this design is the D01MH, a metamorphic GaAs mHEMT with a 0.13 µm channel length. The designed MMIC is expected to convert a 5 dBm, 23–24 GHz input signal into a 11 dBm, 92–96 GHz output signal. Simulations show an output power harmonic suppression over 50 dBc between the desired and unwanted ones. Input and Output matching respectively better than 13 and 16 dB is expected. The MMIC occupies an area of 3 × 2 mm2, and is currently being manufactured.
- Published
- 2019
39. GaN/Si ka-band SPDT for observation payloads
- Author
-
Silvio Fenu, Sergio Colangeli, Ferdinando Costanzo, Patrick E. Longhi, Walter Ciccognani, Ernesto Limiti, and Giorgio Polli
- Subjects
(MMICs) ,Materials science ,Silicon ,Millimeter-wave integrated circuits ,Operating frequency ,Settore ING-INF/01 ,chemistry.chemical_element ,Gallium nitride ,02 engineering and technology ,Gallium nitride on silicon (GaNISi) ,High-electron-mobility transistors (HEMTs) ,Ka-band ,Single-Pole double-Throw (SPDT) switch ,chemistry.chemical_compound ,Resonator ,0202 electrical engineering, electronic engineering, information engineering ,Insertion loss ,Ka band ,Satellite observation ,business.industry ,020208 electrical & electronic engineering ,Bandwidth (signal processing) ,020206 networking & telecommunications ,chemistry ,Optoelectronics ,business - Abstract
This paper presents the design and initial tests of a Gallium Nitride on Silicon (GaN/Si) Single-Pole Double-Throw (SPDT) switch for space-borne satellite observation payloads operating at Ka-band and more precisely around 36GHz. The SPDT is synthesized through a series FET configuration, with inductive resonators, and exhibits (typically) 1.1dB measured insertion loss and 22dB isolation over the 33–39GHz bandwidth. Expected non-linear performance is +39dBm IP1dB. Results and performance are in line with previously published results in open literature but are obtained on a relatively inexpensive and most of all easily accessible Silicon substrate that is known for its higher RF losses with respect to its Silicon-Carbide (SiC) counterpart. To the best of the Authors' knowledge this is one of the first GaN on Silicon SPDTs published in this operating frequency.
- Published
- 2019
40. Design of a MMIC low-noise amplifier in industrial gallium arsenide technology for E-band 5G transceivers
- Author
-
Sergio Colangeli, Walter Ciccognani, Patrick E. Longhi, and Ernesto Limiti
- Subjects
Materials science ,business.industry ,Millimeter wave circuits ,E band ,020206 networking & telecommunications ,02 engineering and technology ,Condensed Matter Physics ,Low-noise amplifier ,Settore ING-INF/01 - Elettronica ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Gallium arsenide ,chemistry.chemical_compound ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Optoelectronics ,Electrical and Electronic Engineering ,Transceiver ,business ,Monolithic microwave integrated circuit ,5G - Published
- 2019
41. A Generalized Unterminating Technique for Characterizing Reciprocal Three-Port Networks
- Author
-
Walter Ciccognani, Sergio Colangeli, Patrick E. Longhi, and Ernesto Limiti
- Subjects
Radiation ,Reciprocal network ,three-port network ,Generalization ,business.industry ,Computer science ,unterminating ,020206 networking & telecommunications ,Port (circuit theory) ,02 engineering and technology ,Extension (predicate logic) ,Condensed Matter Physics ,Topology ,Settore ING-INF/01 - Elettronica ,Software ,Balun ,0202 electrical engineering, electronic engineering, information engineering ,Calibration ,Power dividers and directional couplers ,Electrical and Electronic Engineering ,business ,Reciprocal - Abstract
A novel technique for characterizing reciprocal three-port networks is proposed. The approach is an extension of the conventional unterminating method for characterizing two-port networks: on the one hand, the latter extracts the parameters of a (reciprocal) two-port network from one-port measurements, and on the other hand, the presented generalization extracts the parameters of a (reciprocal) three-port network from two-port measurements. The technique is believed of interest particularly for those which occasionally need to perform three-port vector-corrected measurements of three-port test-bench components such as baluns and directional couplers but do not have access to multiport equipment and software.
- Published
- 2019
42. Design for Manufacturing of Electro-Mechanical Assemblies in the Aerospace Industry
- Author
-
Patrick E. Longhi and Ernesto Limiti
- Subjects
Engineering ,business.industry ,business ,Aerospace ,Settore ING-INF/01 - Elettronica ,Manufacturing engineering ,Design for manufacturability - Published
- 2019
43. UWB Circuits and Sub-Systems for Aerospace, Defence and Security Applications
- Author
-
Patrick E. Longhi and Ernesto Limiti
- Subjects
Engineering ,business.industry ,Systems engineering ,business ,Aerospace ,Settore ING-INF/01 - Elettronica ,Electronic circuit - Published
- 2019
44. A straightforward design technique for narrowband multi-stage low-noise amplifiers with I/O conjugate match
- Author
-
Ernesto Limiti, Sergio Colangeli, Walter Ciccognani, Antonio Serino, Patrick E. Longhi, and Alessandro Salvucci
- Subjects
Computer science ,02 engineering and technology ,Integrated circuit ,Inductor ,Settore ING-INF/01 - Elettronica ,law.invention ,Narrowband ,law ,design methodology ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Linear amplifier ,Electrical and Electronic Engineering ,low-noise amplifiers ,conjugate matching ,noise measure ,Flowchart ,Amplifier ,020208 electrical & electronic engineering ,020206 networking & telecommunications ,Computer Graphics and Computer-Aided Design ,source inductive degeneration ,Computer Science Applications ,Noise ,Electronic design automation - Abstract
Low-noise amplifier (LNA) designers often struggle to simultaneously satisfy gain, noise, stability, and I/O matching requirements. In this article, a novel design technique, tailored for two-stage low-noise amplifiers, is presented. The proposed design method is completely deterministic and exploits inductive source degeneration to obtain a two-stage LNA featuring perfect input and output match together with low noise figure (NF) and a pre-determined gain, including stability analysis. A novel flowchart is provided together with the corresponding design chart that contains gain, matching, and stability information, therefore addressing all key figures-of-merit of a linear amplifier. The design chart is easily implementable in commercial Electronic Design Automation software, to aid designers in the difficult task of selecting the appropriate source degeneration inductor value. The noise performance, on the other hand, is the best possible since the matching networks are designed to provide the input of the two Field Effect Transistors with the optimum termination for noise. The design method is validated with two separate test vehicles operating respectively at Ka-band (26.5-31.5 GHz) and K-band (20.0-24.0 GHz). The realized Monolithic Microwave Integrated Circuits exhibit 18 dB gain for both versions, NF of 1.5 and 1.2 dB, respectively for the Ka-band and K-band version. Input and output matching are typically better than 12 and 15 dB.
- Published
- 2019
45. On the Optimum Noise-Gain Locus of Two-Ports
- Author
-
Walter Ciccognani, Patrick E. Longhi, Ernesto Limiti, and Sergio Colangeli
- Subjects
two-port network ,misura di rumore ,Conformal map ,02 engineering and technology ,extended noise factor ,Noise figure ,Settore ING-INF/01 - Elettronica ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,Reflection coefficient ,Exchangeable gain ,noise measure ,reti due porte ,Guadagno scambiabile ,Physics ,Discrete mathematics ,Radiation ,Noise measurement ,Scattering ,Amplifier ,Guadagno scambiabile, reti due porte, misura di rumore ,Tangent ,020206 networking & telecommunications ,Condensed Matter Physics ,Locus (mathematics) - Abstract
A novel result is presented concerning the locus, on the source reflection coefficient plane, of the optimum tradeoff between noise factor and available gain. Although this locus has been discussed and exploited in previous contributions, here, it is shown in a simple manner that it must be an arc of a circumference with center $C_{\mathrm{ tc}}$ and radius $\rho _{\mathrm{ tc}}$ (tangency circle). A handy transformation (a reversible, conformal one) of two-port networks is adopted to study the problem in a simplified, yet general, representation. Properties of the tangency circle are observed in this “noise-centered” representation which are preserved under the conformal transformation, thus providing two equivalent, closed-form approaches to computing $C_{\mathrm{ tc}}$ and $\rho _{\mathrm{ tc}}$ . The second method presented lends itself to being easily implemented in commercial circuit simulators, thus serving as the basis of a simple design method for single-stage low-noise amplifiers.
- Published
- 2019
46. Design of a 5W Single Chip Front-End for C-Ku Band T/R Modules
- Author
-
Daniele Rampazzo, Diego Palombini, Patrick E. Longhi, and Andrea Bentini
- Subjects
Physics ,Concurrent engineering ,business.industry ,020208 electrical & electronic engineering ,Electrical engineering ,020206 networking & telecommunications ,Gallium nitride ,02 engineering and technology ,Ku band ,Settore ING-INF/01 - Elettronica ,Power (physics) ,Front and back ends ,chemistry.chemical_compound ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Insertion loss ,Electronic warfare ,business ,Monolithic microwave integrated circuit - Abstract
In this contribution an integrated Single Chip Front-End (SCFE) for next generation Electronic Warfare T/R modules is presented. The proposed circuit relies on a concurrent design technique merging switches and HPA matching network. Realized MMIC features a 6.3×4.3mm2 outline operating in the 5.5-18 GHz band with a typical output power of 6W, an associated PAE of 10% and 3dB insertion loss in Rx mode.
- Published
- 2018
47. Generalized Extraction of the Noise Parameters by Means of Source-and Load-Pull Noise Power Measurements
- Author
-
Antonio Serino, Walter Ciccognani, Sergio Colangeli, Ernesto Limiti, and Patrick E. Longhi
- Subjects
Limiting factor ,Noise power ,Radiation ,Noise measurement ,Computer science ,020208 electrical & electronic engineering ,Load pull ,020206 networking & telecommunications ,Context (language use) ,02 engineering and technology ,Condensed Matter Physics ,Settore ING-INF/01 - Elettronica ,Noise ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Extraction (military) ,Electrical and Electronic Engineering ,Electrical impedance - Abstract
This paper is focused on the extraction of the noise parameters of a linear two-port network by exploiting both forward and reverse noise power measurements, thus extending the universally adopted approach in which only forward measurements are involved. The analytical derivation of the constituting relations is detailed and the application to an exemplifying measurement context is reported. A fuller exploitation of the approach may in the future simplify the direct extraction of black-box noise models at very high frequencies, where the difficulty in synthesizing a number of different terminations is the most prominent limiting factor.
- Published
- 2018
48. Thrombosis after liver transplantation for hepatocellular carcinoma
- Author
-
E. Longhi, Sherrie Bhoori, Maria Abbattista, Alberto Maino, Andrea Artoni, Marta Serafini, Ida Martinelli, Tullia Maria De Feo, Giorgio Rossi, Paolo Bucciarelli, Vincenzo Mazzaferro, Umberto Maggi, and Francesca R. Ponziani
- Subjects
RNA viruses ,Male ,medicine.medical_treatment ,lcsh:Medicine ,Hepacivirus ,Cardiovascular Medicine ,Liver transplantation ,Vascular Medicine ,Biochemistry ,Gastroenterology ,Postoperative Complications ,0302 clinical medicine ,Medicine and Health Sciences ,Thrombophilia ,Medicine ,lcsh:Science ,Pathology and laboratory medicine ,Multidisciplinary ,Hepatitis C virus ,Liver Diseases ,Mortality rate ,Liver Neoplasms ,Hematology ,Proteases ,Medical microbiology ,Middle Aged ,Thrombosis ,Enzymes ,Survival Rate ,Venous thrombosis ,Oncology ,Cardiovascular Diseases ,030220 oncology & carcinogenesis ,Viruses ,Prothrombin G20210A ,Female ,030211 gastroenterology & hepatology ,Pathogens ,Research Article ,Hepatitis B virus ,medicine.medical_specialty ,Carcinoma, Hepatocellular ,Death Rates ,Surgical and Invasive Medical Procedures ,Gastroenterology and Hepatology ,Carcinomas ,Microbiology ,Disease-Free Survival ,Digestive System Procedures ,03 medical and health sciences ,Population Metrics ,Internal medicine ,Gastrointestinal Tumors ,Factor V Leiden ,Humans ,Blood Coagulation ,Survival rate ,Aged ,Transplantation ,Coagulation Disorders ,Population Biology ,Flaviviruses ,business.industry ,lcsh:R ,Organisms ,Viral pathogens ,Biology and Life Sciences ,Proteins ,Cancers and Neoplasms ,Organ Transplantation ,Hepatocellular Carcinoma ,medicine.disease ,Hepatitis viruses ,Liver Transplantation ,Microbial pathogens ,Enzymology ,lcsh:Q ,Serine Proteases ,business ,Follow-Up Studies - Abstract
The influence of thrombosis on the prognosis of patients with hepatocellular carcinoma (HCC) after liver transplantation (LT) and the role of the commonest inherited thrombophilia abnormalities factor V Leiden and prothrombin G20210A in the development of thrombosis are unknown. We investigated a cohort of patients who underwent LT for HCC with the aim to estimate the incidence rate (IR) of thrombosis, its influence on mortality and re-transplantation rates and, in the frame of a nested case-control study, the role of thrombophilia in donors and recipients for the development of thrombosis. Four-hundred and thirty patients underwent LT and were followed for a median of 7.2 years. Twenty-six recipients (6%) developed thrombosis (IR 1.06 [95%CI: 0.71-1.53] per 100 pts-yr). Mortality rate after LT was 3.95 (95%CI: 3.22-4.79) per 100 pts-yr and was not influenced by thrombosis. Re-transplantation was planned for 33 patients and was more common in patients with thrombosis than in those without (HR 2.50 [95%CI: 0.87-7.17]). The risk of thrombosis was 4 times higher in recipients with thrombophilia than in those without (OR 4.23 [95%CI: 0.99-18.04]) and 6 times higher when the analysis was restricted to venous thrombosis (OR 6.26 [95%CI: 1.19-32.85]). The presence of inherited thrombophilia in the donors did not increase the risk of thrombosis of the recipient. In conclusion, thrombosis is a complication of 6% of patients transplanted for HCC and increases the risk of re-transplantation but not of mortality. The risk of thrombosis, particularly venous, is increased in the presence of thrombophilia abnormalities in the recipients.
- Published
- 2017
49. Anti-HLA Antibodies before and after Lung Transplantation: A Role on Medium-Long Term Outcomes?
- Author
-
E. Benazzi, Antonino Cannavò, Serena M. Passamonti, Letizia Corinna Morlacchi, Massimo Cardillo, Alessandro Palleschi, Paolo Tarsia, Lorenzo Rosso, Ilaria Righi, B. Dalpedri, Valeria Rossetti, and E. Longhi
- Subjects
Pulmonary and Respiratory Medicine ,Transplantation ,medicine.medical_specialty ,Lung ,biology ,business.industry ,medicine.medical_treatment ,Context (language use) ,Human leukocyte antigen ,Gastroenterology ,body regions ,medicine.anatomical_structure ,Internal medicine ,medicine ,biology.protein ,Long term outcomes ,Lung transplantation ,Surgery ,Risk factor ,Antibody ,Cardiology and Cardiovascular Medicine ,business ,Cohort study - Abstract
Purpose The development of donor specific human leukocyte antigen (HLA) antibodies (DSA) has already been identified as a risk factor for graft dysfunction and poor survival in the context of lung transplantation (LuTx), but available evidence is not conclusive. The aim of our study was to evaluate the possibly existing correlation between pre-existing and/or post transplant developing DSA and recipients’ outcome. Methods This was a prospective, cohort study on consecutive LuTx recipients from January 2013 to December 2017. Every individual underwent DSA surveillance with blood specimens collection before and after LuTx. Three groups were defined based on pre-formed antibody setting at time of LuTx: silent, if no antibody was found on their blood; reactive, patients with non-DSA antibodies; and activated, patient with DSA antibodies. Correlation between antibodies panel (before and after LuTx) and outcomes (lung allograft dysfunction and survival) was then investigated. Results 132 patients were considered; 70 (53%) males, median age at LuTx 36 (26; 51) years. Among the “silent” patients: 63% remained negative after LuTx, 20% developed non-DSA and 17% DSA. Among “reactive” recipients: 15% became negative after LuTx, 39% maintained non-DSA and 46.2% developed de-novo DSA. Finally, considering “activated” individuals: the vast majority (80%) maintained pre-transplant DSA and developed new ones, while the remaining 20% lost pre-transplant DSA but showed de-novo non DSA. DSA tended to appear much earlier in pre-transplant allosensitized patients (1 vs. 3 months). Image 1 depicts these results. Finally, both pre and post LuTx DSA showed correlation with the development of chronic lung allograft dysfunction (CLAD) (HR 3.43; 1.19-9.89 and HR 3.35; 1.46-7.68). Conclusion These preliminary findings support the role of both pre-existing and post LuTx developed DSA as a potentially dangerous risk factor for CLAD development, while they did not correlate with acute cellular rejection and/or survival.
- Published
- 2019
50. Constant Mismatch Circles and Application to Low-Noise Microwave Amplifier Design
- Author
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Walter Ciccognani, Patrick E. Longhi, Sergio Colangeli, and Ernesto Limiti
- Subjects
amplifier noise ,Engineering ,Radiation ,Amplifier figures of merit ,business.industry ,feedback amplifiers ,Amplifier ,microwave field-effect transistor (FET) amplifiers ,Y-factor ,Condensed Matter Physics ,Settore ING-INF/01 - Elettronica ,Low-noise amplifier ,design methodology ,Control theory ,Negative feedback amplifier ,Current sense amplifier ,Electronic engineering ,Instrumentation amplifier ,Electrical and Electronic Engineering ,business ,Direct-coupled amplifier - Abstract
Constant input and output mismatch circles in the output load plane are introduced as the basis for low-noise amplifier design methodology. Optimum tradeoff between input and output matching levels results as the application of a design chart providing, at the same time, the corresponding stage transducer gain. The role of degenerative series feedback is studied and systematically embedded in the design procedure, thus providing a direct way to evaluate its optimum level.
- Published
- 2013
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