Neural-Based Nonlinear Device Models for Intermodulation Analysis

A new procedure to learn a nonlinear model together with its derivative parameters using a composite neural network is presented.So far neural networks have never been used to extract large-signal device model accounting for distortion parameters.Applying this method to FET devices leads to nonlinear models for current- voltage functions which allow improved prediction of weak and mildly device nonlinearities in the whole bias region. The resulting models have demonstrated to be suitable for both small-signal and large-signal analyses,including intermodulation distortion prediction

Rasgos dentales no-métricos en una muestra pre-conquista calchaquí de Argentina, América del Sur

The present study was carried out with a Calchaquí human Pre-Conquest sample from Northwest of Argentina, with the aim of exploring the dental morphology patterns in this population. This study was carried out by means of a macroscopic analysis in permanent dentitions of 7 skulls. 40 dental non-mtetric traits were recorded using the ASU Dental Anthropology System. Percentages >70% was found only in 4 traits. Calchaquí sample studied here is near to these values in shovel shape expression, but the results of this study suggest that a Sinodont pattern is no clear for this sample. To conclude, the present investigation provides additional, insightful elements for a description of biological factors in the process of dental morphologic diversification associated to regional and temporal ranges in this region of Argentina.Facultad de Ciencias Naturales y Muse

A Novel Stacked Cell Layout for High Frequency Power Applications

This letter presents an innovative stacked cell, where the common source device is split in two smaller devices leading to a more compact and symmetric structure, with almost negligible parasitics associated to the transistors connection. This novel configuration is rigorously compared, for the first time, with the two classical approaches commonly adopted to physically connect the two devices. The three different layouts are fabricated in Gallium Nitride technology for high frequency power applications, and experimentally compared by means of an extensive measurement campaign performed on several loads and in different bias conditions, ranging from class AB to C. The proposed novel configuration outperforms the other two in all conditions, thanks to the advantages of adopting two smaller devices with reduced parasitics, higher gain and higher power density. These features are common to different technologies, thus making the novel topology widely applicable for the design of high frequency stacked cells

Automatic Optimization of Input Split and Bias Voltage in Digitally Controlled Dual-Input Doherty RF PAs

Digitally controlled Dual-Input Doherty Power Amplifiers (DIDPAs) are becoming increasingly popular due to the flexible input signal splitting between the main and auxiliary stages. Nevertheless, the presence of many degrees of freedom, e.g., input amplitude split and phase displacement as well as biasing for multiple stages, often involves inefficient trial-and-error procedures to reach a suitable PA performance. This article presents automated parameter setting based on coordinate descent or Bayesian optimizations, demonstrating an improvement in the performance in terms of RF output power and power-added efficiency (PAE) in the presence of broadband-modulated signals, yet maintaining suitable linear behavior for, e.g., communications applications

168-195 GHz Power Amplifier with Output Power Larger Than 18 dBm in BiCMOS Technology

This paper presents a 4-way combined G-band power amplifier (PA) fabricated with a 130-nm SiGe BiCMOS process. First, a single-ended PA based on the cascode topology (CT) is designed at 185 GHz, which consists of three stages to get an overall gain and an output power higher than 27 dB and 13 dBm, respectively. Then, a 4-way combiner/splitter was designed using low-loss transmission lines at 130-210 GHz. Finally, the combiner was loaded with four single-ended PAs to complete the design of a 4-way combined PA. The chip of the fabricated PA occupies an area of 1.35mm 2 . The realized PA shows a saturated output power of 18.1 dBm with a peak gain of 25.9 dB and power-added efficiency (PAE) of 3.5% at 185 GHz. A maximum output power of 18.7 dBm with PAE of 4.4% is achieved at 170 GHz. The 3-dB and 6-dB bandwidth of the PA are 27 and 42 GHz, respectively. In addition, the PA delivers a saturated output power higher than 18 dBm in the frequency range 140-186 GHz. To the best of our knowledge, the power reported in this paper is the highest for G-band SiGe BiCMOS PAs