Armando Fernández Prieto

Universidad de Sevilla | US · Electronic and Electromagnetism

This book takes you on an exciting journey into the world of antennas designed with defected ground structures (DGSs). It covers a wide range of interesting and timely topics. The authors, Prof. Debatosh Guha, Prof. Chandrakanta Kumar, and Prof. Sujoy Biswas, who are globally recognized experts in the field of antennas, have compiled a comprehensiv...

In this paper, glide symmetry is applied to design common-mode rejection filters based on defected ground structures with bandstop response. To this aim, complementary split-ring resonators are chosen as the basic components for common-mode rejection. To illustrate the advantages of using glide symmetry, three implementations are studied and compar...

Extraordinary transmission structures show promising capabilities for highly selective filters in both frequency and angle of incidence. However, their realistic response once manufacturing limitations are taken into account remains unexplored. In this manuscript, we explore a novel degree of freedom: disorder. We expand on previously developed hig...

In this article, the authors propose a lumped circuit methodology for the design of broadband stacked microstrip patch antennas fed through an aperture. First, an equivalent circuit (EC) is introduced for the antenna. The EC consists of an $LC$ series resonator modeling the feed plus two capacitively coupled $LC$ parallel resonators accounting...

Passive planar circuits play a key role in many RF/microwave applications, such as in wireless communications, medical instrumentation, and remote sensing [...]

Two new compact balanced-to-balanced diplexers composed of two multiband balanced bandpass filters in a multilayer configuration are proposed in this letter to perform dual- and tri-band responses. The balanced bandpass filters are based on the use of magnetically coupled open-loop resonators. The magnetic coupling results in a strong inherent comm...

In this article, we present a novel application of glide symmetry to differential lines with common-mode (CM) rejection filter properties. Two different topologies are investigated. First, glide symmetry is applied to a pair of differential lines where ground-connected mushrooms are employed as a CM rejection structure. The same idea is also used i...

In this work, a rigorous approach for the design of a differential coupled-line directional coupler (DCLDC) implemented in double-side coplanar-waveguide (CPW) technology is presented. Due to the double symmetry of the structure, it is possible to obtain the coupling level and port characteristic impedances of the coupler in a simple and efficient...

A new dual-band balanced bandpass filter based on magnetically coupled open-loop resonators in multilayer technology is proposed in this paper. The lower differential passband, centered at the Global Positioning System (GPS) L1 frequency, 1.575 GHz, was created by means of two coupled resonators etched in the middle layer of the structure, while th...

Mushroom-type electromagnetic bandgap (EBG) structures are known to operate as high-impedance surfaces at low-frequency bands. They are broadly used in the microwave regime. However, one of the main drawbacks of mushroom-type EBG structures is their narrow bandwidth. In this article, we propose a mushroom-type EBG structure with glide-symmetric edg...

Passive planar circuits play a key role in many RF/microwave applications, such as wireless communications, medical instrumentation, and remote sensing. Planar technologies were born during World War II but their use did not became popular until the 1960s. Since then, the use of classical planar structures, such as striplines, microstrips, and copl...

This paper presents slow-wave transmission lines based on non-periodic reactive loading. Specifically, the loading elements are stepped impedance shunt stubs (SISS). By sacrificing periodicity using SISS tuned to different frequencies, multiple transmission zeros above the pass band arise, and the rejection level and bandwidth of the stop band is i...

In this study, a compact rat‐race hybrid coupler with harmonic suppression based on slow‐wave transmission lines (SW‐TLs) is presented. Such artificial lines are implemented by periodic loading a host microstrip line with series meandered inductors and shunt patch capacitors. The presence of both loading elements has a twofold effect, i.e. phase ve...

During July 2018, a group of top high school Spanish students attended a summer scientific camp at the University of Seville. The topic of the project was magnetic levitation. During the one-week-long stay, the students investigated several possible ways of achieving stable levitation. These included diamagnetic levitation, use of superconductors,...

A compact, balanced, dual-band bandpass filter with flexible and independent control of the differential-mode response is presented in this study. The filtering mechanism relies on the use of magnetically coupled embedded resonators. This provides two clear advantages: high level of miniaturisation and two differential-mode passbands that can be in...

This document contains supplementary material for the article with the same title that appeared in American Journal of Physics in 2019

A compact branch‐line hybrid coupler with harmonic suppression based on slow‐wave microstrip lines is presented in this paper. These slow‐wave artificial transmission lines are implemented by simultaneously loading a host line with series inductors and shunt capacitors. By this means, the effective capacitance and inductance of the line are increas...

A compact microstrip power splitter based on a pair of 70.71 Ω impedance inverters implemented by means of inductively loaded slow‐wave transmission lines is designed and fabricated. As a result of the slow‐wave effect, associated to the presence of series‐connected semi‐lumped (meandered) inductors, the length of the constitutive inverters is 41%...

This work presents a simple and accurate method for the calculation of both the self-inductance and the mutual inductance between thin-film capacitors, placed in close proximity in electromagnetic interference filters. From physical considerations regarding the impact of both skin and proximity effects, we approximate the currents flowing inside th...

Two balanced-to-balanced planar diplexers based on magnetically coupled microstrip resonators are proposed in this paper. For the first prototype, each channel/differential-output is composed of a second order single-band balanced bandpass filter based on open-loop resonators. For the second diplexer example, the filters composing the differential...

In this paper, an analytical method to estimate the complex dielectric constant of liquids is presented. The method is based on the measurement of the transmission coefficient in an embedded microstrip line loaded with a complementary split ring resonator (CSRR), which is etched in the ground plane. From this response, the dielectric constant and l...

This chapter aims to study some implementations of wideband balanced bandpass filters based on multi-section mirrored stepped impedance resonators (SIRs) and to provide guidelines for their design. Through the use of such resonant elements, it is possible to achieve wideband differential-mode responses and an efficient common-mode rejection by the...

Coupled-resonators are widely used for implementing narrowband bandpass filters, which are essential components for many RF/microwave applications. This chapter starts by designing a balanced single-band bandpass filter based on conventional coupled resonators. Next, several types of common-mode (CM) rejection stages (which are the basic unit cells...

Narrowband bandpass filters (BPFs) are key components in modern communication systems and other applications of wireless technologies. This chapter discusses balanced filter topologies where common-mode (CM) is inherently rejected due to the geometric properties (including symmetry) of the proposed structures. It also discusses several examples of...

This chapter reviews the main strategies for common-mode suppression in differential-mode transmission lines. It presents some examples of common-mode suppression filters for differential microstrip lines, based on patterned ground planes (or defected ground structures). These common-mode filters exhibit significant common-mode rejection bandwidths...

A compact balanced-to-balanced diplexer composed of two balanced bandpass filters is proposed in this letter. The balanced filters are implemented using compact edge-coupled square split-ring resonators. The design methodology is based on the standard coupled-resonators filter synthesis procedure. First, each filter is independently designed. Then,...

In this paper, a slow-wave transmission line implemented in coplanar waveguide technology, based on simultaneous inductive and capacitive loading, is presented for the first time. The shunt capacitors are achieved by periodically etching transverse strips in the back substrate side, connected to the central strip through metallic vias. The series i...

Common-mode rejection filters operating at microwave frequencies have been the subject of intensive research activity over the last decade. These filters are of interest for the suppression of common-mode noise in high-speed digital circuits, where differential signals are widely employed due to the high immunity to noise, electromagnetic (EM) inte...

A symmetrical pair of differential microstrip lines implemented in hybrid microstrip/coplanar waveguide (CPW) technology is proposed. Transmission-line models are used to analyze differential- and common-mode responses, allowing efficient design with minimal optimization effort. The structure behaves as a conventional transmission line pair under d...

A new compact balanced dual-band bandpass filter based on coupled-embedded resonators with modified ground plane is presented in this work. Common-mode is rejected within the two differential passbands by symmetrically introducing four coupled U-shaped defected ground structures below the resonators. Common-mode rejection is significantly improved...

A novel balanced differential bandpass filter implemented in coplanar waveguide (CPW) technology is presented. The filter is based on the use of two magnetically coupled CPWfolded-stepped impedance resonators. The use of magnetic coupling, instead of the more common electric coupling, provides inherent common-mode rejection. Measured and simulated...

A unifying principle explaining the numerical bounds of quantum correlations remains elusive despite the efforts devoted to identify it. Here we show that these bounds are indeed not exclusive to quantum theory: for any abstract correlation scenario with compatible measurements, a suited classical wave theory produces probability distributions indi...

A new multilayer differential transmission line for common-mode suppression fabricated using an organic liquid crystal polymer multilayer substrate is proposed and analysed. The structure consists of a pair of parallel strip lines printed on the top layer of the substrate that are capacitively coupled to conductor patches periodically etched in an...

A simple strategy is proposed to design differential-mode bandpass filters with good common-mode (CM) rejection using simple resonators. Specifically, the CM rejection is enhanced by using conventional open-loop resonators as well as folded stepped-impedance resonators without the addition of printed or lumped elements along the symmetry plane of t...

This paper presents a novel approach for the implementation of balanced ultra-wideband (UWB) bandpass filters with common-mode noise suppression. To a first-order approximation, the differential-mode filter response is described by the canonical circuit model of a bandpass filter, i.e., a cascade of series-connected resonators alternating with shun...

A novel balanced bandpass filter (BPF) based on folded stepped impedance resonators (FSIR's) with modified ground plane is presented in this work. By symmetrically introducing a series-LC resonant structure below the FSIR's, common-mode (CM) propagation can be rejected without affecting differential-mode (DM) performance. The filter presents two ma...

This paper investigates the effects of inter-resonator coupling in metamaterial transmission lines loaded with split ring resonators (SRRs). The study is performed from Bloch mode theory applied to the multiport equivalent circuit model of the unit cell of such artificial lines. From this analysis, it follows that the stopband bandwidth, inherent t...

This letter presents a compact differential-mode (balanced) power splitter with filtering capability and dual-band functionality. This multifunctional device is based on differential-mode composite right/left-handed (DM-CRLH) transmission lines specifically designed to achieve the dual-band behavior and to suppress the common-mode noise over a broa...

This paper is focused on the analysis of the propagation characteristics of periodic structures consisting of a host line loaded with split ring resonators (SRRs). It is well known that these structures exhibit stop band functionality in the vicinity of the resonance frequency of the SRRs, and propagation is forward in the transmission bands. Howev...

A novel strategy for the design of common-mode suppressed differential (or balanced) filters, based on stepped impedance resonators (SIRs), is presented. The differential mode band pass response is achieved by coupling parallel LC resonators, implemented by a patch capacitance and a grounded inductance, through admittance inverters. Such inverters...

Differential (balanced) microstrip bandpass filters (BPFs) implemented by combining open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs) are proposed. The OSRRs are series connected in both strips of the differential line, whereas the OCSRRs are paired face-to-face and connected between both line strips in a symm...

A new balanced dual-band bandpass filter with strong common-mode rejection is presented in this paper. Common-mode rejection is provided by a section of a periodic microstrip differential line that behaves as a low-pass filter under common-mode operation. In contrast, the differential line exhibits very good all-pass behavior under differential mod...

Transmission-line metamaterials based on complementary split-ring resonators (CSRRs) are shown to support forward, backward, electroinductive, and complex waves. Two CSRR-based lines are considered: 1) stopband microstrip lines simply loaded with CSRRs, and 2) passband microstrip lines loaded with CSRRs and series gaps. The effects of interresonato...

This paper is focused on the application of complementary split-ring resonators (CSRRs) to the suppression of the common (even) mode in microstrip differential transmission lines. By periodically and symmetrically etching CSRRs in the ground plane of microstrip differential lines, the common mode can be efficiently suppressed over a wide band where...

This work reports on a modified version of λ/2 open stubs bandpass filters (λ/2‐OSBPFs) and λ/4 open stubs bandstop filters (λ/4‐OSBSFs) for wide/narrow bandwidth operation. When wide bandwidths (for λ/2‐OSBPF) or narrow bandwidths (for λ/4‐OSBSF) are required, conventional microstrip implementation of this kind of filters is not possible owing to...

A novel microstrip differential transmission line with common-mode noise suppression is proposed and experimentally validated. It is implemented by periodically etching complementary split ring resonators (CSRRs) in the ground plane. For the differential signals, the symmetry of the structure efficiently cancels the electric field components axial...

A novel microstrip differential transmission line for broadband common-mode rejection is proposed. The basic unit cell of the artificial transmission line consists of a pair of coupled lines with a slot in the ground plane in which a conductor patch has been etched. This patch is symmetrically series connected to the ground plane by means of high i...

Modified coplanar waveguide (CPW) edge-coupled band-pass filters with floating conductor strips printed below the coupled-line sections are proposed. These structures allow one to suppress the first undesired spurious passband associated with the nonhomogeneous nature of the dielectric in CPW structures. Also, tight coupling levels can be easily ac...

This letter presents a methodology to reproduce at microwave frequencies the physical behavior of certain diffraction structures that have been investigated in the optics community. The methodology will be exemplified with a microstrip circuit implementation of a transmission line system exhibiting an electromagnetic response that mimics the respon...

This contribution presents a microstrip implementation of a system exhibiting an electromagnetic response that mimics the response of compound diffraction gratings investigated in the optics community. The transmission response of periodic structures of this kind has attracted a lot of attention in the frame of the so called extraordinary transmiss...