A miniature microstrip patch antenna array with defected ground structure

The aim of this work is to miniaturize a microstrip patch antenna array resonating at 10 GHz. It presents an improved method of size reduction of a microstrip antenna array with circular polarisation using Defected Ground Structure (DGS) which is used to perform serious LC resonance property in certain frequency. By integrating Defected Ground Structure elements, the resonance frequency was shifted from 10 GHz to 7.5 GHz. The proposed structure of DGS is incorporated in the ground plane of our array antenna. Prototype of the antenna was fabricated with FR4 substrate and tested. The simulation and measurement results were in good agreement

On the use of a new class of simplified multi-window iris notch in the design of ultra-compact high-rejection waveguide filters for satellite links

This work introduces a simplified multi-aperture iris notch suitable for designing waveguide filters having an extremely improved compactness/rejection ratio, regarding available solutions, and adequate pass-band performances. The proposed iris architecture, analyzed for the first time, exhibits a unique transmission zero in the waveguide mono-mode bandwidth which can be easily located below or above the pass-band. The frequency of this transmission zero is evaluated in terms of the iris dimensions thus providing useful guidelines for designing filters with suitable responses. As a consequence of this simplified topology, any designed filter can be easily manufactured by cutting along its E-field symmetry plane. This strategy greatly improves the filter’s insertion loss regarding classical implementations based on more complicated arrangements with piled thin metallic sheets. Two exemplary filters have been designed and tested to be used in a high-performance X-band SATCOM terminal with an 80% size reduction with respect to the existing systems. Both filters covering the Rx (7.25–75 GHz) and Tx (7.9–8.4 GHz) sub-bands show a reflection of −25 dB with insertion losses below 1 dB in the pass-band, whereas they present a very sharp out-of-band rejection of at least 90 dB, that is, a 600 dB/GHz slope at X band.This work was supported by the State Research Agency, Spanish Ministry of Economy, Industry and Competitiveness, through project TEC2017-83343-C4-1-R and FEDER funds from the EU

Reducing side lobes of antenna array by the binomial method

This paper explores optimization and synthesis of linear, which prints antennas arrays. The developed synthesis bases on an optimization binomial method. The objective of this paper is to adapt the binomial method to reduce the side lobe level. The application of this formalism gives terrific results

Design and implementation of a technology planar 4x4 butler matrix for networks application

In this paper, switched beam smart antenna systems are investigated to improve the performance of wireless networks. The microstrip technology of antenna arrays with Butler matrix topology as a beam-former is used to implement the switched beam smart antenna system. The optimum design of a 4x4 planar Butler matrix array, operating at 5.6 GHz for WLAN applications. System’s design and optimization was based on computer simulations

Filtro de rechazo de banda

Un filtro de rechazo de banda de frecuencias, que comprende: - en una cara superior, una línea microstrip; - en una cara inferior, al menos dos celdas resonantes, cada celda conformada por un trazado en un plano de tierra de al menos cuatro circunferencias concéntricas en una configuración de anillo con corte donde la banda de frecuencias a rechazar se determina mediante uno o más parámetros de diseño que se seleccionan entre: - Anchura de la línea microstrip - Radio de la circunferencia interior - Anchura de las dos celdas - Separación entre las dos celdas - Separación entre dos circunferencias concéntricas consecutivas - Anchura del corte en cada celda.Solicitud: 2015500640 (01.09.2015)Nº Pub. de Solicitud: ES2563247A1 (11.03.2016

Estructura transductora de modos de guía de onda basada en secciones octogonales

Estructura transductora de modos para la conversión de señales electromagnéticas entre una guía de onda de entrada y una guía de onda de salida, teniendo dichas guías de onda de entrada y salida igual o distinta geometría. La estructura transductora de modos comprende una pluralidad de secciones de guía octogonales concatenadas donde dichas secciones de guía octogonales comparten los mismos ejes de simetría entre sí y con dicha guía de onda de entrada y con dicha guía de onda de salida, y donde los parámetros geométricos de dichas secciones de guía octogonales están diseñados y ajustados para acondicionar progresivamente los modos de propagación electromagnéticos entre dicha guía de onda de entrada y dicha guía de onda de salida. Proporciona un ancho de banda superior al de otras técnicas anteriores. Además, la simetría eléctrica y magnética que proporciona la estructura octogonal elimina de forma efectiva la excitación de los modos superiores. Es aplicable en sistemas de transmisión y recepción de señales electromagnéticas a las frecuencias de microondas, milimétricas y sub-milimétricas.Solicitud: 201100440 (15.04.2011)Nº Pub. de Solicitud: ES2394819A1 (05.02.2013)Nº de Patente: ES2394819B2 (14.06.2013

The use of the fluorescente for the study of the water quality

We present a work proposal now in course that is based on the study of the fluorescence in cyanobacteria and toxicity, and the possibility of detecting their presence in freshwater environment, with a direct application in water assessment. The proposal is a consequence of a previous study about the fluorescence generated by hydrocarbon residue on the sea surface. In the first part of this work we present a review of results obtained from the analysis of hydrocarbon samples from the “prestige” oil spill accident and other referential hydrocarbons. In the second part we show the capability of this technique for the development of probes to explore the water quality

Miniaturized microstrip patch antenna with defected ground structure

The aim of this work is to miniaturize a microstrip patch antenna resonating at 3 GHz. For this purpose, defected ground structure (DGS) has been employed to shift the resonance frequency of an initial microstrip antenna from 5.7 GHz to 3 GHz by disturbing the antenna's current distribution. The proposed DGS is incorporated in the ground plane under the patch antenna to improve its performances. Finally, a miniaturization up to 50%, with respect to the conventional microstrip antenna, is successfully accomplished. A prototype of the antenna was fabricated with the FR4 substrate and tested. The measurements results were in good agreement with simulation results

Accurately modeling of Zero Biased Schottky-Diodes at millimeter-wave frequencies

This paper presents and discusses the careful modeling of a Zero Biased Diode, including low-frequency noise sources, providing a global model compatible with both wire bonding and flip-chip attachment techniques. The model is intended to cover from DC up to W-band behavior, and is based on DC, capacitance versus voltage, as well as scattering and power sweep harmonics measurements. Intensive use of 3D EM (ElectroMagnetic) simulation tools, such as HFSSTM, was done to support Zero Biased Diode parasitics modeling and microstrip board modeling. Measurements are compared with simulations and discussed. The models will provide useful support for detector designs in the W-band.This research was funded by the Spanish Ministry of Economy, Science and Innovation for the financial support provided through projects CONSOLIDER-INGENIO CSD2008-00068 (TERASENSE), the continuing excellence network SPATEK and the projects TEC2014-58341-C4-1-R and TEC2017-83343-C4-1-R

Nonlinear modeling of trapping and thermal effects on GaAs and GaN MESFET/HEMT devices

A novel nonlinear model for MESFET/HEMT devices is presented. The model can be applied to low power (GaAs) and high power (GaN) devices with equal success. The model provides accurate simulation of the static (DC) and dynamic (Pulsed) I-V characteristics of the device over a wide bias and ambient temperature range (from -70ºC to +70ºC) without the need of an additional electro-thermal sub-circuit. This is an important issue in high power GaN HEMT devices where self-heating and current collapse due to traps is a more serious problem. The parameter extraction strategy of the new model is simple to implement. The robustness of the model when performing harmonic balance simulation makes it suitable for RF and microwave designers. Experimental results presented demonstrate the accuracy of the model when simulating both the small-signal and large-signal behavior of the device over a wide range of frequency, bias and ambient temperature operating points. The model described has been implemented in the Advanced Design System (ADS) simulator to validate the proposed approach without convergence problems.The authors would like to thank the Spanish Ministry of Science and Innovation (MICINN) by the financial support provided through projects CSD2008-00068, TEC2008-06684-C03-01 and TEC2011-29126-C03-01