Selective mode suppression in microstrip differential lines by means of electric-LC (ELC) and magnetic-LC (MLC) resonators

CIMITECIn this paper, it is demonstrated that the so-called electric-LC (ELC) resonators, and their dual counterparts, the magnetic-LC (MLC) resonators, are useful for the selective suppression of either the differential or the common mode in microstrip differential lines. The key point to mode suppression is the alignment of the resonator with the electric (differential mode) or magnetic (common mode) wall of the line. It is shown that by simply rotating the resonators 90∘ we can selectively choose the suppressed mode in the vicinity of the resonator's fundamental resonance frequency. The theory is validated through full-wave electromagnetic simulation, the lumped element equivalent circuit models of the proposed structures and experimental data

S-shaped complementary split ring resonators and their application to compact differential bandpass filters with common-mode suppression

This letter presents an S-shaped complementary split ring resonator (S-CSRR) for application in compact differential filters. The working principle of the proposed S-CSRR is explained and a circuit model is developed and validated through electromagnetic simulations. It is shown that an S-CSRR-loaded differential microstrip line with series gaps can be used in the design of compact differential bandpass filters (BPFs) with common-mode suppression. The filter design procedure is explained and the theoretical concept is validated through fabrication and measurement of a compact (0.09 λg 0.25 λg) third-order differential BPF with common-mode suppression

Common-mode suppressed differential bandpass filter based on open complementary split ring resonators fabricated in microstrip technology without ground plane etching

A differential (or balanced) bandpass filter based on open complementary split ring resonators (OCSRRs) coupled through admittance inverters is presented in this article. Pairs of OCSRRs are symmet- rically placed in a mirror configuration between the strips of the differential line and are modeled by means of two series connected parallel resonators. For the differential (odd) mode, there is a virtual ground at the connecting plane between the OCSRR pairs, and the structure is roughly described by the canonical model of a bandpass filter, consisting of a cascade of shunt resonators coupled through admittance inverters. It is demonstrated that, through a proper design of the OCSRR stages, the common mode noise in the vicinity of the differential filter pass band can be efficiently suppressed. Due to the differential mode operation of the filter, it is not necessary to incorporate metallic vias to ground the OCSRRs. Moreover, as compared to other differential filters based on OCSRRs, defected ground structures are not present in the proposed filters. To illustrate the potential of the approach, two balanced bandpass filters are designed, fabricated, and characterized

Diseño e implementación de un filtro paso banda de banda estrecha con topología interdigital a frecuencias UHF y microondas

Desde el área de Ingeniería de RF del consorcio CELLS y en el marco de un convenio de colaboración firmado con el grupo de antenas y sistemas de microondas del Departamento de Telecomunicación e Ingeniería de sistemas de la ETSE (UAB), se ha planteado la evaluación y construcción de un filtro que formará parte del lazo de control en el módulo de RF. El objetivo es eliminar una señal espuria que se encuentra a la salida de un mezclador en banda lateral única, que por limitaciones en los inbalanceos de ganancia y fase, no termina de cancelar suficientemente la banda rechazada. Por lo tanto, el trabajo surge de la necesidad de diseñar un filtro capaz de obtener una respuesta paso banda centrada a 520 MHz, para atenuar un espurio existente a una frecuencia cercana (530 MHz). En consecuencia, estas especificaciones proporcionarán al filtro la característica de banda estrecha.Nota: Aquest document conté originàriament altre material i/o programari només consultable a la Biblioteca de Ciència i Tecnologia

Diseño e implementación de un receptor multifrecuencia basado en muestreo paso banda aplicado al sistema Galileo

Este trabajo tiene como objetivo diseñar e implementar un receptor multifrecuencia requerido para aplicaciones Galileo centradas a realizar correcciones de errores y estudios de la ionosfera. Estas características obligan a buscar alternativas respecto los receptores superheterodinos convencionales dado que para éstos los retardos de propagación entre las diferentes bandas de interés son inaceptables. Por ello, se presenta un receptor basado en la técnica de muestreo paso banda, que permite trasladar el espectro mediante el conversor ADC a través de un aliasing intencionado, eliminando así los retardos de propagación entre bandas de interés, dado que todas se albergan en un mismo canal. En este trabajo nos hemos centrado únicamente en las etapas críticas del receptor presentado, siendo éstas la etapa de filtrado y conversión digital. La etapa de filtrado requerirá filtros muy selectivos, ya que el ruido existente fuera de banda se solapará a nuestra banda de interés, degradando la SNR del sistema a medida que tenga más potencia. Esta etapa se ha realizado mediante una estructura duplexora conjuntamente con dos filtros de líneas acopladas. La etapa de conversión se ha realizado fabricando el layout de un conversor comercial, del cual se ha validado el correcto funcionamiento para la aplicación requerida.Aquest treball té com objectiu dissenyar i implementar un receptor multi-freqüència requerit per aplicacions Galileo centrades a realitzar correccions d'errors i estudis de la ionosfera. Aquestes característiques obliguen a buscar alternatives respecte els receptors superheterodins convencionals donat que per aquests, els retards de propagació entre les diferents bandes d'interès són inacceptables. Per això, es presenta un receptor basat en la tècnica de mostreig passa banda, que permet traslladar l'espectre mitjançant el conversor ADC a través d'un aliasing intencionat, eliminant així els retards de propagació entre bandes d'interès, donat que totes s'alberguen en un mateix canal. En aquest treball ens hem centrat únicament en les etapes crítiques del receptor presentat, essent aquestes l'etapa de filtrat i conversió digital. La etapa de filtrat requerirà filtres molt selectius, ja que el soroll existent fora de banda es solaparà a la banda d'interès, degradant així la SNR del sistema a mesura que aquest tingui més potència. Aquesta etapa s'ha realitzar mitjançant una estructura duplexora conjuntament amb dos filtres de línees acoblades. L'etapa de conversió s'ha realitzat fabricant el layout d'un conversor comercial, del qual s'ha validat el correcte funcionament per la aplicació requerida.The purpose of this work is to design and implement a multi-frequency receiver required to Galileo applications aimed to make error corrections and ionosphere studies. These characteristics require using alternatives to the conventional superheterodine receivers, owing to the existing propagation delays between the bands are unacceptable. Thus, a band-pass sampling receiver is presented. This receiver realizes a frequency translation via intentional aliasing, allowing to have the same propagation delays between bands due to all the bands are in a same channel. In this work we only present those stages which are critical for the presented receiver, being these the filter and digital conversion stages. The filter stage requires very selective filters because all the out-of-band noise will be overlapped to the interest band. Thus, the more noise power exists, the more the SNR of the system will be degraded. The filter has been done using a duplexer structure along with two parallel-coupled, half-wavelength resonator filters. The conversion stage has been done realizing the layout of a comercial ADC. With this one, the correct performance of the ADC for the required application has been validated

Split rings-based differential transmission lines with common-mode suppression

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 to the CSRRs, and these particles have no effect on signal transmission. However, the CSRRs are activated under common mode excitation, with the result of a stop-band behavior. For the designed and fabricated prototype device, over 20 dB suppression of common-mode noise is achieved over a frequency range from 1.18 GHz to 1.74 GHz.Ministerio de Ciencia e Innovació TEC2010-17512, CSD2008-00066Generalitat de Catalunya 2009SGR-42

Differential bandpass filters with common-mode suppression based on stepped impedance resonators (SIRs)

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 are implemented by means of 90 o transmission lines, whereas the grounded inductances are implemented by means of mirrored stepped impedance resonators (SIR). For the differential mode, the symmetry plane is a virtual ground, the wide strip section of the SIR is effectively grounded, and the SIR behaves as a shunt inductance. However, for the common mode, where the symmetry plane is an open (magnetic wall), the SIR is a shunt connected series resonator, providing a transmission zero, which can be used for the rejection of the common mode in the differential filter pass band. The equivalent circuit model of the proposed structure is validated through electromagnetic simulation and experimental data of order-3 and -5 Chebyshev differential bandpass filters. Moreover, guidelines for the design of balanced filters with wide bandwidths, including ultra-wideband (UWB) bandpass filters, are provided.Ministerio de Ciencia e Innovación TEC2010-17512, CSD2008-00066Generalitat de Catalunya 2009SGR-42

Common-mode suppression in microstrip differential lines by means of complementary split ring resonators: Theory and applications

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 whereas the differential signals are not affected. Throughout the paper, we present and discuss the principle for the selective common-mode suppression, the circuit model of the structure (including the models under even- and odd-mode excitation), the strategies for bandwidth enhancement of the rejected common mode, and a methodology for common-mode filter design. On the basis of the dispersion relation for the common mode, it is shown that the maximum achievable rejection bandwidth can be estimated. Finally, theory is validated by designing and measuring a differential line and a balanced bandpass filter with common-mode suppression, where double-slit CSRRs (DS-CSRRs) are used in order to enhance the common-mode rejection bandwidth. Due to the presence of DS-CSRRs, the balanced filter exhibits more than 40 dB of common-mode rejection within a 34% bandwidth around the filter pass band.Ministerio de Ciencia e Innovación TEC2010-17512, TEC2010-16948, TEC2011-13615-E, CSD2008-00066Generalitat de Catalunya 2009SGR-421, VALTEC08-1-000

Novel Sensors Based on the Symmetry Properties of Split Ring Resonators (SRRs)

The symmetry properties of split ring resonators (SRRs) are exploited for the implementation of novel sensing devices. The proposed structure consists of a coplanar waveguide (CPW) loaded with movable SRRs on the back substrate side. It is shown that if the SRRs are placed with the slits aligned with the symmetry plane of the CPW, the structure is transparent to signal propagation. However, if the symmetry is broken, a net axial magnetic field can be induced in the inner region of the SRRs, and signal propagation is inhibited at resonance. The proposed structures can be useful as alignment sensors, position sensors and angle sensors. This novel sensing principle is validated through experiment