Pablo Luis López Espí

Pablo Luis López Espí
University of Alcalá | UAH · Department of Signal and Communications Theory

PhD

About

50
Publications
10,950
Reads
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286
Citations
Citations since 2017
10 Research Items
192 Citations
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2017201820192020202120222023010203040
2017201820192020202120222023010203040
2017201820192020202120222023010203040
Additional affiliations
July 2011 - present
University of Alcalá
Position
  • Professor (Associate)

Publications

Publications (50)
Article
Full-text available
A miniaturized helical antenna is presented in this work. The antenna is flexible, it is 6100 μm long and it has a diameter of 352 μm. This antenna has such a small cross-section, that permits to be implanted in the human body with fine syringes and minimally invasive surgeries. The antenna can be used to receive power and/or send information in me...
Article
Full-text available
We describe the application of ISE&PPOOA MBSE methodology and trade-off to select the best technology to implement a building element (block) of an intravascular medical device represented in the system modular architecture. It is important to understand these aspects: • The ISE&PPOOA methodology explains how to select trade-off criteria to constru...
Article
Full-text available
A textile multi-band antenna for LTE and 5G communication services, composed by a rectangular microstrip patch, two concentric annular slots and a U-Shaped slot, is considered in this paper. In the ground plane, three sleeved meanders have been introduced to modify the surface current distribution, leading to a bandwidth improvement. The U-Shaped s...
Article
Full-text available
In recent years, the study and design of wearable antennas have been empowered given the success of Wireless Body Area Networks (WBAN) for healthcare and medical purposes. This work analyses a flexible textile antenna whose performance can be optimised by the careful selection of the substrate thickness of the textile material, and by varying the a...
Article
Full-text available
The image processing of mammograms is very important for the early detection of breast pathologies, including cancer. This paper proposes a new technique based on directional fractal filtering for detecting microcalcification clusters or irregularly shaped microcalcifications. The proposed algorithm has two parts: a preprocessing step for detecting...
Article
Full-text available
This paper proposes a low-profile textile-modified meander line Inverted-F Antenna (IFA) with variable width and spacing meanders, for Industrial Scientific Medical (ISM) 2.4-GHz Wireless Body Area Networks (WBAN), optimized with a novel metaheuristic algorithm. Specifically, a metaheuristic known as Coral Reefs Optimization with Substrate Layer (C...
Article
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The aim of this study is the detailed calculation of microwave propagation inside raw timber in cylindrical configurations. Two different approaches have been used. The first one uses an exact formulation and analytical approximations in order to explore the electromagnetic field distribution inside dry wood. The introduction of conductivity in the...
Article
Electromagnetic radiowave exposure is a major concern in most countries due to possible adverse health effects. Over the last 10years, many technological changes (digital television, mobile technologies, wireless networks…) have led to variations in the electromagnetic field (EMF) levels. A large number of studies devoted to the analysis of EMF lev...
Article
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The main aim is to test the influence of anatomical structure (grain direction and elements size), wood hardness and machining conditions on wood surface roughness. 180 samples defect-free were obtained from beech, oak and pine and processed with different machining methods (planning, sanding with 60 grit or sanding with 180 grit). Roughness, hardn...
Article
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This paper presents the design of a tree sections corrugated horn antenna with a modified linear profile, using NURBS, suitable for radio-astronomy applications. The operating band ranges from 4.5 to 8.8 GHz. The aperture efficiency is higher than 84% and the return losses are greater than 20 dB in the whole bandwidth. The antenna optimization has...
Article
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In this work a simple technique to obtain information about the species of wood samples using stress-wave sounds in the audible range is presented. However, spectra of wood sounds generated by pendulum impact are very complex and feature extraction for classification purposes is very difficult. Polyspectral techniques have been successfully applied...
Conference Paper
This paper presents a low profile multiband antenna suitable for future wireless communication systems. The design comprises a co-planar fed patch antenna and a planar inverted-F antenna (PIFA). Active switching enables the antenna to resonant in different lower frequency bands while maintaining fixed operational performance in the upper bands.
Article
Full-text available
In this paper, we propose the optimization of the parameters of a hybrid antenna for wireless applications by using a multi‐objective evolutionary programming (EP). Specifically, the antenna proposed is formed by a planar inverted‐F antenna and a coplanar patch, in the same structure. The objective functions to carry out the optimization process ar...
Conference Paper
This work describes the optimization process of a dual band antenna by using two evolutionary method: Evolutionary Programming (EP) and Particle Swarm (PSO). These techniques have been used to increase the bandwidth of each band. The bandwidth criterion is that the return loss must be less or equal to -10dB. The antenna has been made by two single...
Article
Full-text available
Palatal clicks are most interesting for human echolocation. Moreover, these sounds are suitable for other acoustic applications due to their regular mathematical properties and reproducibility. Simple and nondestructive techniques, bioinspired by synthetized pulses whose form reproduces the best features of palatal clicks, can be developed. The use...
Article
Full-text available
In the first part of this work we studied several oral signals suitable for human echolocation. Palatal clicks were proven to be optimal pulses for this task. In the second part of this series, we analyze, from a physical and psychoacoustical point of view, the sounds produced by hand clapping and finger snapping. One additional sound is studied: a...
Article
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This paper presents an application of evolutionary computation algorithms in the estimation of the concentration of nitrates/nitrites in water. Specifically, we start from the measured transmittance curves of a water sample and a model of the curve consisting of a mixture of polynomial, Fermi and Gaussian functions. An evolutionary programming algo...
Conference Paper
In this paper we present a study of the application of a Particle Swarm Optimization (PSO) and a Variable Neighborhood Search (VNS) algorithms to the estimation of the concentration of nitrates in water. Our study starts from the definition a model for the Ultra-violet spectrophotometry transmittance curves of water samples with nitrate content. T...
Article
Full-text available
One of the non-conventional technologies of wastewater treatment applicable to small communities is the land application system (LAS) or “filtros verdes”, as this technique is called in Spanish. A correct design of LAS may imply to know the mode of occurrence and efficiency of the infiltration. Thus, the geophysical method of electric resistivity t...
Article
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This paper analyzes the application of different bio-inspired and heuristic techniques to the problem of curve fitting in experimental chemistry applications. Two different curve models are considered, the well-known Pearson VII function, used before in different curve fitting applications, and a novel hybrid model for transmittance curves, mainly...
Article
Full-text available
Active human echolocation can be an extremely useful aid for blind people. Active echolocation can be trained with both artificial and organic signals. Organic signals offer some advantages over artificial ones. Very detailed studies of organic signals in animals have been done. However, in the case of humans, the scientific literature is very scar...
Article
Verilog-A Hardware Description Language (VHDL) is a behavioral description language for analog systems. It is derived from the IEEE 1364 Verilog HDL specification and it is intended to let designers of analog and integrated circuits to create and use modules described mathematically in terms of its terminals and external parameters applied to the m...
Conference Paper
Full-text available
The paper presents a short survey of some topics related to speed control of electrical drives based on fuzzy PI controllers. In the beginning the conventional control systems of the main three motors mostly used in practice: DC motors, induction motors ...
Conference Paper
Full-text available
The long term impact of microwave communication technologies will be functionality simulated and design on traditional computing and usual RF and microwave communication simulators such us: PSPICE, Agilent ADS, Agilent GENESYS, AWR Microwave Office, etc. This ability, allows making possible the enabling of the digital computer interaction and simul...
Article
Speckle noise reduction techniques are very important for the enhancement and preprocessing of SAR and many medical images. We present a fast and efficient algorithm, based on fractal convolutions, to reduce speckle noise in real SAR images. The results of this approach are compared with other classical noise reduction techniques.
Article
Full-text available
An accurate full vectorial treatment of the leaky modes in Bragg fibres with high refractive index variations is presented. The model can describe arbitrary functions of the relative permittivity inside the fibre. Boundary conditions are substituted by smooth continuous functions. This allows the use of very precise numerical and analytical approac...
Article
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Complete vectorial studies of electromagnetic wave propagation in complex media are difficult and computationally intensive. A mathematical continuous model can simplify some of such difficulties. Using this technique, we have modeled the propagation of electromagnetic plane waves through a semiinfinite photonic crystal with defects. The model is e...
Article
This paper presents a low cost system developed for finding vehicles by means of a GPS system. By using several applications, it is possible to know the position of a vehicle on a map, send messages... The applications are independent of the employed radiocomunication system. Circuitry has been developed with commercial devices and different applic...
Conference Paper
The main objective of this work is to develope a software tool that allows studying the reticular network planning in hectometrics wavelengths. This tool is intended to perform the pratical teaching about surface wave broadcasting in the educational laboratory. The program has been developed using MATLAB 6.
Conference Paper
Full-text available
In this paper, we present several techniques of digital image processing that can be used in the recovering of damaged graphical documents. The ancient graphical documents give an important information in several subjects like history, ethnography or architecture reconstruction and then a good conservation and recovering is an important issue. The...
Article
Full-text available
This paper deals with the application of time-frequency decompositions and principal component analysis for improving the performance of a neural network for radar detection. This approach is compared with a simpler neural detector, designed as a multilayer feed-forward network that works with raw data. The proposed detector can be split in three p...
Article
Slow fluctuating radar targets have shown to be very difficult to classify by means of neural networks. This paper deals with the application of time-frequency decompositions for improving the performance of neural networks for this kind of targets. Several topics, such as dimensionality reduction of the time-frequency representations and the optim...
Article
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Resumen: El programa desarrollado permite la edición, análisis y simulación de circuitos eléctricos formados por generadores y/o impedancias de distintos tipos bajo el entorno multitarea Windows. Ofrece por tanto un entorno amigable para la edición gráfica de los circuitos además de proporcionar información sobre el análisis en el dominio temporal...
Article
Full-text available
In this paper, a new family of nearly perfect transmultiplexers based on cosine-modulated filter banks is presented. These filter banks are obtained using a new prototype filter design technique that controls the position of the passband cutoff frequency to minimize an objective function. The resulting transmultiplexers have good frequency selectiv...
Article
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We present in this paper a software tool that let the user simulate the overall optical system response. We can evaluate it for those ones that use either rectangular pulses or digitally modulated signals in order to transmit information by means of optical fibber, monomode or multimode, and in first, second or third optical window. This applicatio...
Article
Full-text available
This paper presents a software tool developed for simulating optical communications systems. The optical system is divided into three main parts: transmitter, optical fibber and receiver. The simulation allows the determinations of the spectral and frequency responses of each block and the whole system. The program allows the simulations of the dif...
Article
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El gran avance tecnológico producido en los últimos años en el ámbito de las comunicaciones, ha incrementado la complejidad de los dispositivos de RF y microondas. Todo ello ha ido acompañado de un refinamiento de las herramientas CAD de alta frecuencia utilizadas en simulación, exigiéndoles que muestren la máxima fidelidad posible a la realidad de...
Article
Full-text available
The study of contamination levels in wastewater is very important for health, economic and legal reasons. European Directive 2000/60/CE establishes the quality levels for groundwater. It also binds control between other nitrate concentration. In this work, we show a method based on evolutionary programming for estimating nitrate concentration in a...
Article
Full-text available
This paper describes the development of a tool for the application of the knowledge on waveguides, and its equivalent transmission line model to the design of several microwave waveguide circuits. We purpose the creation of user's models for the simulation program MMICAD, starting from the equivalent circuits of discontinuities in rectangular and c...
Article
Full-text available
This document presents an application where neural networks with variable size and parameters are applied to radar targets detection. These parameters are: number of layers, neurons in every layer, learning rate and momentum. These parameters allow the choice of the network that match better with your problem. We have successfully used neural netwo...
Article
Full-text available
In this paper we present the study of electromagnetic simulation as an educational tool for microwave filters. We have started from the classic coupled lines filter, simulated both by traditional and electromagnetic methods. This way, we can obtain the frequency response and also the electric field distribution. Later, we have introduced ladder lin...

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Projects (2)
Project
Researching new highly penetrating, no ionizing, high quality imaging sensors for medical and nondestructive testing applications.