Design of a 87% fractional bandwidth Doherty Power Amplifier supported by a simplified bandwidth estimation method

This paper presents a novel technique for the design of broadband Doherty power amplifiers (DPAs), supported by a simplified approach for the initial bandwidth estimation that requires linear simulations only. The equivalent impedance of the Doherty inverter is determined by the value of the output capacitance of the power device, and the Doherty combiner is designed following this initial choice and using a microstrip network. A GaN-based single-input DPA designed adopting this method exhibits, on a state-of-the-art bandwidth of 87% (1.5-3.8 GHz), a measured output power of around 20 W with 6 dB back-off efficiency between 33% and 55%, with a gain higher than 10 dB. System-level measurements prove the linearizability of the designed Doherty amplifier when a modulated signal is applied

A differential combiner for quasi-complete cancellation of output capacitance in mm-wave power amplifiers with high- Q devices

This article proposes a new and simpler methodology to combine two transistors for high-frequency applications. By using a λ/4 transmission line to connect the drain pads of the identical transistors, the line characteristic impedance can be chosen to almost perfectly cancel out the output capacitance at the design frequency f0 . When the combined network is loaded with a real impedance, the real part of the impedance seen at each of the intrinsic devices is twice the value of that load, while the imaginary part is exactly zero for one of the transistors and depends on f0 for the other. This imaginary part is inversely proportional to f0 and becomes relatively small with high Q -factor (defined as product between optimum intrinsic load and output capacitance susceptance) devices at the frequency of operation ( f0 ). To demonstrate the effectiveness of this methodology, a 28-GHz Doherty power amplifier (DPA) based on the NP15 microwave monolithic integrated circuit (MMIC) process from WIN Semiconductors, Taoyuan, Taiwan, has been designed using the proposed combining method for the main and auxiliary branches. The continuous wave (CW) characterization of this amplifier shows competitive results, which are comparable with the state-of-the-art in terms of efficiency, output power, gain, and bandwidth. Over a band between 27.5 and 29.5 GHz, the obtained saturated output power is higher than 32 dBm. The power added efficiency (PAE) at 6-dB output back-off (OBO) is in the range of 21%–24%, while it is from 24% to 34% at saturation. The saturated gain is between 8 and 12 dB over the abovementioned band

A 0.6–3.8 GHz GaN Power Amplifier Designed Through a Simple Strategy

This letter presents the design strategy for an ultrawideband, high-efficiency hybrid power amplifier based on a commercial GaN-HEMT. The measurement results demonstrate a state-of-the-art fractional bandwidth of 145.5%, with saturated output power higher than 10 W from 0.6 to 3.8 GHz and power added efficiency exceeding 46% in the whole band, thus covering most of the mobile frequencies and making this device suitable for small-base station applications. The simple design approach exploits a N-section transformer, and allows for a priori estimation of the bandwidth: in the proposed case, a good agreement between estimated and measured bandwidth is obtaine

Automatización del proceso de generación del seguro estudiantil, aplicando las tecnologías rfid y gprs

This article presents the description of the design and implementation of a system which allows the fulfilment of a consultation service on various parameters to a web server using a GSM modem, exchanging information systems over the Internet (ISS) and radio-frequency identification (RFID). The application validates for its use in automation of the process of generation of the student insurance, and hardware and software, developed by the Research Group in Robotics and Industrial Automation GIRAof UPTC, are used as a platform.En este artículo se presenta la descripción del diseño e implementación de un sistema que permite el despliegue de un servicio de consultas de diversos parámetros a un servidor de Internet, utilizando un módem GSM, sistemas de intercambio de información a través de Internet (ISS) e identificación de usuarios mediante radiofrecuencia (RFID). La aplicación se valida por su uso en la automatización del proceso de generación del seguro estudiantil, y se emplean como plataforma el software y el hardware desarrollados por el Grupo de Investigación en Robótica y Automatización Industrial GIRAde la UPTC

A K-band GaAs MMIC Doherty power amplifier for point-to-point microwave backhaul applications

This work reports the design of a GaAs monolithic K-band Doherty power amplifier for point-to-point microwave backhaul applications. The design of the module is described, from the choice of the architecture based on power budget and gain requirements, to the analysis of the solutions adopted. The MMIC is expected to achieve 32.5 dBm output power in the 20.8-24 GHz band, PAE higher than 32% at saturation (20% at 6 dB output back-off) and gain higher than 10 d

3-20 GHz GaN MMIC Power Amplifier Design Through a COUT Compensation Strategy

This paper presents the design approach for a compact, single-stage, wideband MMIC power amplifier. A method is proposed to compensate the output capacitance of the active device over a frequency range as wide as possible, with minimum impact on the achievable output power, that leads to a 2- element compensating network. A 3- section transformer is then adopted for a real-to-real transformation. The CW characterization shows output power higher than 32dBm and drain efficiency between 35% and 45%, over a fractional bandwidth of 148%, from 3 GHz to 20 GHz

Surrogate indices of insulin resistance using the Matsuda index as reference in adult men—a computational approach

Background: Overweight and obesity, high blood pressure, hyperglycemia, hyperlipidemia, and insulin resistance (IR) are strongly associated with non-communicable diseases (NCDs), including type 2 diabetes, cardiovascular disease, stroke, and cancer. Different surrogate indices of IR are derived and validated with the euglycemic–hyperinsulinemic clamp (EHC) test. Thus, using a computational approach to predict IR with Matsuda index as reference, this study aimed to determine the optimal cutoff value and diagnosis accuracy for surrogate indices in non-diabetic young adult men. Methods: A cross-sectional descriptive study was carried out with 93 young men (ages 18–31). Serum levels of glucose and insulin were analyzed in the fasting state and during an oral glucose tolerance test (OGTT). Additionally, clinical, biochemical, hormonal, and anthropometric characteristics and body composition (DEXA) were determined. The computational approach to evaluate the IR diagnostic accuracy and cutoff value using difference parameters was examined, as well as other statistical tools to make the output robust. Results: The highest sensitivity and specificity at the optimal cutoff value, respectively, were established for the Homeostasis model assessment of insulin resistance index (HOMA-IR) (0.91; 0.98; 3.40), the Quantitative insulin sensitivity check index (QUICKI) (0.98; 0.96; 0.33), the triglyceride-glucose (TyG)-waist circumference index (TyG-WC) (1.00; 1.00; 427.77), the TyG-body mass index (TyG-BMI) (1.00; 1.00; 132.44), TyG-waist-to-height ratio (TyG-WHtR) (0.98; 1.00; 2.48), waist-to-height ratio (WHtR) (1.00; 1.00; 0.53), waist circumference (WC) (1.00; 1.00; 92.63), body mass index (BMI) (1.00; 1.00; 28.69), total body fat percentage (TFM) (%) (1.00; 1.00; 31.07), android fat (AF) (%) (1.00; 0.98; 40.33), lipid accumulation product (LAP) (0.84; 1.00; 45.49), leptin (0.91; 1.00; 16.08), leptin/adiponectin ratio (LAR) (0.84; 1.00; 1.17), and fasting insulin (0.91; 0.98; 16.01). Conclusions: The computational approach was used to determine the diagnosis accuracy and the optimal cutoff value for IR to be used in preventive healthcare.Fil: Malagón Soriano, Víctor Antonio. Universidad Nacional de Colombia; ColombiaFil: Ledezma Forero, Andres Julian. Universidad Nacional de Colombia; ColombiaFil: Espinel Pachon, Cristian Felipe. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Burgos Cárdenas, Álvaro Javier. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Garces, Maria Fernanda. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Ortega Ramírez, Gustavo Eduardo. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Franco Vega, Roberto. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Peralta Franco, Jhon Jairo. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Maldonado Acosta, Luis Miguel. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Rubio Romero, Jorge Andres. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Mercado Pedroza, Manuel Esteban. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Caminos Cepeda, Sofia Alexandra. Universitat Pompeu Fabra; EspañaFil: Lacunza, Ezequiel. Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Inmunológicas Básicas y Aplicadas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Rivera Moreno, Carlos Armando. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Darghan Contreras, Aquiles Enrique. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Ruiz Parra, Ariel Iván. Universidad Nacional de Colombia. Facultad de Medicina; ColombiaFil: Caminos, Jorge E.. Universidad Nacional de Colombia. Facultad de Medicina; Colombi

Surrogate indices of insulin resistance using the Matsuda index as reference in adult men—a computational approach

BackgroundOverweight and obesity, high blood pressure, hyperglycemia, hyperlipidemia, and insulin resistance (IR) are strongly associated with non-communicable diseases (NCDs), including type 2 diabetes, cardiovascular disease, stroke, and cancer. Different surrogate indices of IR are derived and validated with the euglycemic–hyperinsulinemic clamp (EHC) test. Thus, using a computational approach to predict IR with Matsuda index as reference, this study aimed to determine the optimal cutoff value and diagnosis accuracy for surrogate indices in non-diabetic young adult men.MethodsA cross-sectional descriptive study was carried out with 93 young men (ages 18–31). Serum levels of glucose and insulin were analyzed in the fasting state and during an oral glucose tolerance test (OGTT). Additionally, clinical, biochemical, hormonal, and anthropometric characteristics and body composition (DEXA) were determined. The computational approach to evaluate the IR diagnostic accuracy and cutoff value using difference parameters was examined, as well as other statistical tools to make the output robust.ResultsThe highest sensitivity and specificity at the optimal cutoff value, respectively, were established for the Homeostasis model assessment of insulin resistance index (HOMA-IR) (0.91; 0.98; 3.40), the Quantitative insulin sensitivity check index (QUICKI) (0.98; 0.96; 0.33), the triglyceride-glucose (TyG)-waist circumference index (TyG-WC) (1.00; 1.00; 427.77), the TyG-body mass index (TyG-BMI) (1.00; 1.00; 132.44), TyG-waist-to-height ratio (TyG-WHtR) (0.98; 1.00; 2.48), waist-to-height ratio (WHtR) (1.00; 1.00; 0.53), waist circumference (WC) (1.00; 1.00; 92.63), body mass index (BMI) (1.00; 1.00; 28.69), total body fat percentage (TFM) (%) (1.00; 1.00; 31.07), android fat (AF) (%) (1.00; 0.98; 40.33), lipid accumulation product (LAP) (0.84; 1.00; 45.49), leptin (0.91; 1.00; 16.08), leptin/adiponectin ratio (LAR) (0.84; 1.00; 1.17), and fasting insulin (0.91; 0.98; 16.01).ConclusionsThe computational approach was used to determine the diagnosis accuracy and the optimal cutoff value for IR to be used in preventive healthcare

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe