Dual-Band Tunable Recursive Active Filter

This letter presents a novel recursive active filter topology that provides dual-band performance, with independent tuning capability in both bands. The dual-band operation is achieved by using two independent feedback lines. Additionally, linear phase shifters based on left-handed cells are included in these two branches in order to tune the center frequency of both pass bands

Design method for actively matched antennas with non-foster elements

The design of electrically small antennas (ESAs) loaded with active non-Foster elements is a topic whose interest has grown in the last years. In this communication, a new strategy for the design of actively matched antennas loaded with non-Foster elements is presented. The analysis of different parameters, such as the sensitivity to non-Foster circuit placement, the overall antenna system stability, and current distributions, has to be considered in order to enhance the antenna performance. A design example using an ESA and its realization is presented to validate the proposed strategy.This work was supported in part by MINECO under the project TEC2013-47753-C3-2-R and RTC 2014-2380-4.Publicad

Mortero de cemento Portland con parafinas microencapsuladas

Se muestran resultados y análisis de características físicas y mecánicas de morteros con PCM

Connection of Converters to a Low and Medium Power DC Network Using an Inductor Circuit

CONVOCATORIA 2013 - PROYECTOS I+D+I - PROGRAMA ESTATAL DE INVESTIGACIÓN, DESARROLLO E INNOVACIÓN ORIENTADA A LOS RETOS DE LA SOCIEDADThis paper describes an alternative to connect power converters to a direct-current network with an inductor circuit. The circuit allows the connection of converters through a coil and avoids short-circuit currents with different instantaneous values of voltage output. A description of the calculation and the choice of components together with a real implemented example in a dc network within Smart City project (Endesa Utility) is presented. Aplicación en el Smart City Project de Endesa en MálagaPlan Nacional de Investigación ref.: ENE2013-46205-C5-5-

PWM strategy with harmonics injection and modulated frequency triangular carrier. A review.

Política de acceso abierto tomada de: https://www.icrepq.com/re&pqj/open-access/RE&PQJ-Open-Access.pdfEn este artículo se presenta una nueva técnica de modulación de ancho de pulso (PWM) programada para controlar inversores de potencia, que utiliza un modulador de inyección armónica y una portadora triangular de frecuencia modulada, sincronizada con la señal moduladora. La frecuencia portadora instantánea se ajusta según una función periódica sincronizada con el término fundamental de la señal moduladora, con el fin de mantener el valor promedio de la frecuencia instantánea como un múltiplo entero positivo impar de 3, para cada período de la señal moduladora, lo cual se conoce como orden de modulación promedio. Las ventajas de utilizar la técnica propuesta sobre las técnicas PWM convencionales son la reducción de la distorsión armónica total y el aumento de la frecuencia de los armónicos temporales para cualquier orden de modulación promedio. Los resultados experimentales muestran la viabilidad de optimizar los armónicos de tiempo generados para minimizar las vibraciones en un motor de inducción o evitar las frecuencias resonantes. Se define la formulación matemática para el voltaje modulado de salida y los resultados también se verifican experimentalmente y se comparan con una técnica PWM sinusoidal.This work was funded by Spanish National Research Plan (2015–2017) with grant no. ENE2013-46205-C5-5-R

Antena de Parche Monopolar de Doble Frecuencia

A dual-frequency patch antenna with monopolar radiation patterns at both working frequencies is presented in this paper. The antenna design is based on a conventional patch with two concentric short-circuited conditions with a separating gap between them. Both shorting conditions are implemented with vias between the patch and the ground plane. These conditions impose two modes with a uniform electric field distribution both in phase and amplitude at the edge of the patch antenna. These modes result in a monopolar radiation pattern at two different frequencies. The working frequencies can be arbitrary set and depend on the patch dimensions and the location of the shorting vias. Two feeding strategies have been studied: a single coaxial probe which excites both monopolar modes and a different coaxial probe for each mode. A two-port design working at 2.6 GHz and 4.8 GHz is presented, obtaining the desired monopolar radiation pattern at both frequencies. High isolation between the feeding ports is achieved

Filtro Activo Recursivo con Divisores de Potencia Metamaterial Asimétricos

In this work, it is presented a recursive active filter implemented by means of unequal Wilkinson power dividers. These power combiners have been implemented by using metamaterial transmission lines based on complementary split ring resonators (CSRRs). The power dividers are designed in planar technology and thanks to the use of the metamaterial cells their dimensions have been reduced. Additionally, the designed recursive active filter presents a high gain and low noise at the same time that minimizes the number of employed lumped elements

Pulse width modulation technique with harmonic injection in the modulating wave and discontinuous frequency modulation for the carrier wave to reduce vibrations in asynchronous machines.

Política de acceso abierto tomada de: https://v2.sherpa.ac.uk/id/publication/25179A new carrier-based pulse-width modulation (PWM) technique to control power inverters is presented in this study. To generate the output waveform, this technique compares a harmonic-injection modulating wave and a frequency-modulated triangular carrier wave. The instantaneous frequency for the carrier wave is adjusted according to a periodic function synchronised with the fundamental term of the modulating wave. The main motivation for using this technique compared to a classic PWM sinusoidal technique revolves around the reduction of total harmonic distortion, the reduction of the distortion factor and the shift of temporal harmonics to higher frequencies for any modulation frequency order. Experimental results show that it is possible to optimise the time harmonics generated to minimise vibrations produced by an induction motor when it is fed with a DC/AC converter controlled by the proposed control strategy. This is made possible by using a control parameter that modifies the instantaneous frequency of the carrier wave without modifying the number of pulses per period of the modulating wave, i.e. the mean value of the carrier wave frequency. The proposed technique is applied to an open loop-controlled inverter that operates an induction motor, helping to reduce the vibration levels produced.This work was funded by Spanish National Research Plan (2015–2017) with grant no. ENE2013-46205-C5-5-R

Recursive Active Filter with Metamaterial Unequal Wilkinson Power Dividers

In this work, it is shown that it is possible to implement an unequal Wilkinson power divider with reduced dimensions by using metamaterial transmission lines based on complementary split ring resonators (CSRRs), in planar technology. In addition, this combiner has been used to implement a compact recursive active filter. Thanks to the use of the metamaterial combiner it is possible obtain a filter with small dimensions. Additionally, due to the asymmetry in the power divider it is possible obtain high gain and low noise at the same time that minimizes the number of lumped element

Estudio y Estrategias de diseño para amplificadores de doble banda de alto rendimiento. Estructuras con líneas CRLH y ECRLH.

In this paper two methods to design dual band and high efficiency power amplifiers using Composite Right/Left Hand (CRLH) and Extended Composite Right/Left Hand (ECRLH) transmission lines are described. The CRLH and ECRLH transmission lines, design procedure and design equations are presented. As example of application the design of an CE class amplifier appears. The non-linear phase response of a CRLH and ECRLH transmission line has been utilized to design arbitrary dual-band amplifiers. The simulations results are presented at the end of the paper, demonstrating the validity of the use of this type of lines in the design of amplifiers