A TRIPLE-MODE BANDPASS FILTER USING A MODIFIED CIRCULAR PATCH RESONATOR

This article presents a triple-mode bandpass filter using a modified circular patch resonator. Etched slots in the resonator split the TM(1, 1, 0)(z) degenerate fundamental modes and also perturb the TM(2, 1, 0)(z) mode, approximating their resonant frequencies to form a third-order bandpass filter. A 2.42 GHz centered filter was designed and fabricated. Experimental results showed a fractional bandwidth of 29%, return loss better than 16 dB, insertion loss of 0.5 dB, and good second harmonic band rejection. The filter exhibited a size reduction of 51% compared with a filter using an unperturbed circular patch resonator at the same frequency. (C) 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 178-182, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23950

A Triple-mode Sigma-delta Modulator Design for Wireless Standards

This work presents a triple-mode sigma-delta modulator for three wireless standards namely GSM/WCDMA and Bluetooth. A reconfigurable ADC has been used to meet the wide bandwidth and high dynamic range requirements of the multi-standard receivers with less power consumption. A highly linear sigma-delta ADC which has reduced sensitivity to circuit imperfections has been chosen in our design. This is particularly suitable for wide band applications where the oversampling ratio is low. Simulation results indicate that the modulator achieves a peak SNDR of 84/68/68 dB over a bandwidth of 0.2/3.84/1.5 MHz with an oversampling ratio 128/8/8 in GSM/WCDMA/Bluetooth modes respectively

A Triple-Mode Feed-Forward Sigma-Delta Modulator Design For Gsm / Wcdma / Wlan Applications

This paper presents a cascaded 2-2-2 reconfigurable sigma-delta modulator that can handle GSM, WCDMA and WLAN standards. The modulator makes use of a low-distortion swing suppression topology which is highly suitable for wide band applications. In GSM mode, only the first stage (2nd order Σ-Δ ADC) is turned on to achieve 88dB dynamic range with oversampling ratio of 160 for a bandwidth of 200KHz; in WCDMA mode a 2-2 cascaded structure (4th order) is turned on with 1-bit in the first stage and 2-bit in the second stage to achieve 74 dB dynamic range with oversampling ratio of 16 for a bandwidth of 2MHz and a 2-2-2 cascaded MASH architecture with a 4-bit in the last stage to achieve a dynamic range of 58dB for a bandwidth of 20MHz. The novelty lies in the fact that unused blocks of second and third stages can be switched off taking into considerations like power consumption. The modulator is designed in TSMC 0.18um CMOS technology and operates at 1.8 supply voltage.

Analysis of a Reconfigurable Bandpass Circular Patch Filter

This paper presents an analysis of a reconfigurable patch filter based on a triple-mode circular patch resonator with four radial slots. The analysis has been carried out thanks to the development of a new theoretical approach of the tunable patch filter based on the coupling matrix. The coefficients of the coupling matrix related to the tunable behavior have been identified and some rules for their evolution have been derived. For a proof-of-concept, a bandpass filter has been designed with a continuous tunability obtained with varactors connected across the slots. State-of-the-art results have been obtained, with a frequency tuning range of 27% from 1.95 to 2.43 GHz and a change in fractional bandwidth from 8.5% to 31.5% for the respective frequencies. In the entire tuning range, the return loss is better than 10 dB and the maximum insertion loss is 2 dB. Due to the newly developed coupling matrix, measurements, simulations, and theory showed great agreement.

A Multi-Mode Sigma-Delta ADC for GSM/WCDMA/ WLAN Applications

The demand for new telecommunication services requiring higher capacities, data rates and different operating modes have motivated the development of new generation multi-standard wireless transceivers. In multistandard design, sigma-delta based ADC is one of the most popular choices. To this end, in this paper we present cascaded 2-2-2 reconfigurable sigma-delta modulator that can handle GSM, WCDMA and WLAN standards. The modulator makes use of a low-distortion swing suppression topology which is highly suitable for wide band applications. In GSM mode, only the first stage (2nd order Σ-Δ ADC) is used to achieve a peak SNDR of 88dB with oversampling ratio of 160 for a bandwidth of 200KHz and for WCDMA mode a 2-2 cascaded structure (4th order) is turned on with 1-bit in the first stage and 2-bit in the second stage to achieve 74 dB peak SNDR with over-sampling ratio of 16 for a bandwidth of 2MHz. Finally, a 2-2-2 cascaded MASH architecture with 4-bit in the last stage is proposed to achieve a peak SNDR of 58dB for WLAN for a bandwidth of 20MHz. The novelty lies in the fact that unused blocks of second and third stages can be made inactive to achieve low power consumption. The modulator is designed in TSMC 0.18um CMOS technology and operates at 1.8 supply voltage

Bottle microresonators for applications in quantum optics and all-optical signal processing

This thesis reports on the experimental realization, characterization and application of a novel microresonator design. The so-called “bottle microresonator” sustains whispering-gallery modes in which light fields are confined near the surface of the micron-sized silica structure by continuous total internal reflection. While whispering-gallery mode resonators in general exhibit outstanding properties in terms of both temporal and spatial confinement of light fields, their monolithic design makes tuning of their resonance frequency difficult. This impedes their use, e.g., in cavity quantum electrodynamics (CQED) experiments, which investigate the interaction of single quantum mechanical emitters of predetermined resonance frequency with a cavity mode. In contrast, the highly prolate shape of the bottle microresonators gives rise to a customizable mode structure, enabling full tunability. The thesis is organized as follows: In chapter I, I give a brief overview of different types of optical microresonators. Important quantities, such as the quality factor Q and the mode volume V, which characterize the temporal and spatial confinement of the light field are introduced. In chapter II, a wave equation calculation of the modes of a bottle microresonator is presented. The intensity distribution of different bottle modes is derived and their mode volume is calculated. A brief description of light propagation in ultra-thin optical fibers, which are used to couple light into and out of bottle modes, is given as well. The chapter concludes with a presentation of the fabrication techniques of both structures. Chapter III presents experimental results on highly efficient, nearly lossless coupling of light into bottle modes as well as their spatial and spectral characterization. Ultra-high intrinsic quality factors exceeding 360 million as well as full tunability are demonstrated. In chapter IV, the bottle microresonator in add-drop configuration, i.e., with two ultra-thin fibers coupled to one bottle mode, is discussed. The highly efficient, nearly lossless coupling characteristics of each fiber combined with the resonator's high intrinsic quality factor, enable resonant power transfers between both fibers with efficiencies exceeding 90%. Moreover, the favorable ratio of absorption and the nonlinear refractive index of silica yields optical Kerr bistability at record low powers on the order of 50 µW. Combined with the add-drop configuration, this allows one to route optical signals between the outputs of both ultra-thin fibers, simply by varying the input power, thereby enabling applications in all-optical signal processing. Finally, in chapter V, I discuss the potential of the bottle microresonator for CQED experiments with single atoms. Its Q/V-ratio, which determines the ratio of the atom-cavity coupling rate to the dissipative rates of the subsystems, aligns with the values obtained for state-of-the-art CQED microresonators. In combination with its full tunability and the possibility of highly efficient light transfer to and from the bottle mode, this makes the bottle microresonator a unique tool for quantum optics applications.

Microwave Characterisation of BaCe2Ti5O15 and Ba5Nb4O15 Ceramic Dielectric Resonators Using Whispering Gallery Mode Method

A microwave dielectric ceramic resonator based on BaCe2Ti5O15 and Ba5Nb4O15 have been prepared by conventional solid state ceramic route. The dielectric resonators (DRs) have high dielectric constant 32 and 40 for BaCe2Ti5O15 and Ba5Nb4O15, respectively. The whispering gallery mode (WGM) technique was employed for the accurate determination of the dielectric properties in the microwave frequency range. The BaCe2Ti5O15 and Ba5Nb4O15 have quality factors (Q X F) of 30,600 and 53,000 respectively. The quality factor is found to depend on the azimuthal mode numbers. The temperature coefficient of resonant frequency (Tr) of BaCe2Ti5O15 and Ba5Nb4O15 have been measured accurately using different resonant modes and are + 41 and + 78 ppm/K, respectively

High sensitivity biosensors based on shear mode AIN resonators for in liquid operation

El diagnóstico y detección temprana de enfermedades son clave para reducir la tasa de mortalidad, las hospitalizaciones de larga duración y el desaprovechamiento de recursos. En los últimos años se ha impulsado, mediante un aumento de la financiación, el desarrollo de nuevos biosensores de bajo coste capaces de detectar y cuantificar cantidades muy pequeñas de especies biológicas de una forma barata y sencilla. El trabajo presentado en esta Tesis Doctoral describe la investigación llevada a cabo en el desarrollo de sensores gravimétricos basados en resonadores de ondas acústicas de volumen (BAW) de estructura maciza (SMR). Los dispositivos emplean películas delgadas de A1N como material piezoeléctrico y operan en modo de cizalladura, para así poder detectar especies biológicas en medio líquido. El principio de funcionamiento de estos sensores se basa en la variación que experimenta la frecuencia de resonancia al quedar una pequeña masa adherida a su superficie. Necesitan operar en modo de cizalladura para que su resonancia no se atenúe al trabajar en medio líquido, así como ofrecer una superficie capaz de ser funcionalizada específicamente para la especie biológica a detectar. El reto planteado en esta tesis requiere un acercamiento pluridisciplinar al problema que incluye el estudio de los diferentes materiales que constituyen la estructura multicapa que forma un SMR, el diseño y fabricación del dispositivo y del sistema de fluídica, la funcionalización bioquímica de la superficie del sensor, la demostración de la capacidad de detección de especies biológicas y finalmente el diseño y fabricación de la electrónica asociada para la detección de la señal eléctrica. Todas esas tareas han sido abordadas en las distintas etapas del desarrollo de esta tesis y las contribuciones más relevantes se describen en el documento. En el campo de desarrollo de los materiales, se propone un proceso en dos etapas para la pulverización reactiva de capas de A1N que contengan microcristales inclinados capaces de excitar el modo de cizalladura. Se caracteriza la velocidad acústica del modo de cizalladura en todos los materiales que componen la estructura, con el fin de poder obtener un diseño más adecuado del reflector acústico. Se propone un nuevo tipo de material aislante de alta impedancia acústica consistente en capas de W03 pulverizadas que presenta ciertas ventajas tecnológicas frente a las capas convencionales de Ta205. Respecto del diseño del transductor, se estudia la influencia que tienen los con tactos eléctricos extendidos del resonador necesarios para poder adaptar el sistema de fluídica a la estructura. Los resultados indican que es necesario trabajar sobre sustratos aislantes (tanto el soporte como el espejo acústico) para evitar efectos parásitos asociados al uso de capas metálicas bajo los electrodos del resonador que dañan su resonancia. Se analiza la influencia de las diferentes capas del dispositivo en el coeficiente de temperatura de la frecuencia (TCF) del resonador llegando a la conclusión de que las dos últimas capas del reflector acústico afectan significativamente al TCF del SMR, pudiendo reducirse ajusfando adecuadamente sus espesores. De acuerdo con los resultados de estos estudios, se han diseñado finalmente resonadores SMR operando a f .3 GHz en modo de cizalladura, con un área activa de 65000 /xm2, contactos eléctricos que se extienden f .7 mm y factores de calidad en líquido de f 50. Las extensiones eléctricas permiten adaptar el resonador a un sistema de fluídica de metacrilato. Para la detección de especies biológicas se realiza un montaje experimental que permite circular 800 ¡A por la superficie del sensor a través de un circuito cerrado que trabaja a volumen constante. La circulación de soluciones iónicas sobre el sensor descubierto pone de manifiesto que las altas frecuencias de operación previenen los cortocircuitos y por tanto el aislamiento de los electrodos es prescindible. Se desarrolla un protocolo ad-hoc de funcionalización basado en el proceso estándar APTESGlutaraldehído. Se proponen dos alternativas novedosas para la funcionalización de las áreas activas del sensor basadas en el uso de capas de oxidación de Ir02 y su activación a través de un plasma de oxígeno que no daña al dispositivo. Ambos procesos contribuyen a simplificar notablemente la funcionalización de los sensores gravimétricos. Se utilizan anticuerpos y aptámeros como receptores para detectar trombina, anticuerpo monoclonal IgG de ratón y bacteria sonicadas. Una calibración preliminar del sensor con depósitos de capas finas de Si02 de densidad y espesor conocidos permite obtener una sensibilidad de 1800 kHz/pg-cm2 y un límite de detección of 4.2 pg. Finalmente se propone el prototipo de un circuito electrónico de excitación y lectura de bajo coste diseñado empleando teoría de circuitos de microondas. Aunque su diseño y funcionamiento admite mejoras, constituye la última etapa de un sistema completo de bajo coste para el diagnóstico de especies biológicas basado en resonadores SMR de A1N. ABSTRACT Early diagnosis and detection of diseases are essential for reducing mortality rate and preventing long-term hospitalization and waste of resources. These requirements have boosted the efforts and funding on the research of accurate and reliable means for detection and quantification of biological species, also known as biosensors. The work presented in this thesis describes the development and fabrication of gravimetric biosensors based on piezoelectric AlN bulk acoustic wave (BAW) solidly mounted resonators (SMRs) for detection of biological species in liquid media. These type of devices base their sensing principles in the variation that their resonant frequency suffers when a mass is attached to their surface. They need to operate in the shear mode to maintain a strong resonance in liquid and an adequate functionalisation of their sensing area to guarantee that only the targeted molecules cause the shift. The challenges that need to be overcome to achieve piezoelectric BAW resonators for high sensitivity detection in fluids require a multidisciplinary approach, that include the study of the materials involved, the design of the device and the fluidic system, the biochemical functionalisation of the active area, the experimental proof-of-concept with different target species and the design of an electronic readout circuit. All this tasks have been tackled at different stages of the thesis and the relevant contributions are described in the document. In the field of materials, a two-stage sputtering deposition process has been developed to obtain good-quality AlN films with uniformly tilted grains required to excite the shear mode. The shear acoustic velocities of the materials composing the acoustic reflector have been accurately studied to ensure an optimum design of the reflector stack. WO3 sputtered films have been proposed as high acoustic impedance material for insulating acoustic reflectors. They display several technological advantages for the processing of the resonators. Regarding the design, a study of the influence of the electrical extensions necessary to fit a fluidic system on the performance of the devices has been performed. The results indicate that high resistivity substrates and insulating reflectors are necessary to avoid the hindering of the resonance due to the parasitic effects induced by the extensions. The influence of the different layers of the stack on the resultant TCF of the SMRs has also been investigated. The two layers of the reflector closer to the piezoelectric layer have a significant influence on the TCF, which can be reduced by modifying their thicknesses accordingly. The data provided by these studies has led to the final design of the devices, which operate at 1.3 GHz in the shear mode and display an active area of 65000 /xm2 and electrical extensions of 1.7 mm while keeping a Qahear=150 in liquid. The extensions enable to fit a custom-made fluidic system made of methacrylate. To perform the biosensing experiments, an experimental setup with a liquid closed circuit operating at constant flow has been developed. Buffers of ionic characteristics have been tested on non-isolated devices, revealing that high operation frequencies prevent the risk of short circuit. An ad-hoc functionalisation protocol based on the standard APTES - Glutaraldehyde process has been developed. It includes two new processes that simplify the fabrication of the transducers: the use of IrO2 as oxidation layer and its functionalisation through an O2 plasma treatment that does not damage the resonators. Both antibodies and aptamers are used as receptors. In liquid sensing proof-of-concept experiments with thrombin, IgG mouse monoclonal antibody and sonicated bacteria have been displayed. A preliminary calibration of the devices using SiO2 layers reveals a sensitivity of 1800 kHz/pg-cm2 and a limit of detection of 4.2 pg. Finally, a first prototype of a low-cost electronic readout circuit designed using a standard microwave approach has been developed. Although its performance can be significantly improved, it is an effective first approach to the final stage of a portable low-cost diagnostic system based on shear mode AlN SMRs.

Use Of Experimental Design To Optimize A Triple-potential Waveform To Develop A Method For The Determination Of Streptomycin And Dihydrostreptomycin In Pharmaceutical Veterinary Dosage Forms By Hplc-pad.

An HPLC-PAD method using a gold working electrode and a triple-potential waveform was developed for the simultaneous determination of streptomycin and dihydrostreptomycin in veterinary drugs. Glucose was used as the internal standard, and the triple-potential waveform was optimized using a factorial and a central composite design. The optimum potentials were as follows: amperometric detection, E1=-0.15V; cleaning potential, E2=+0.85V; and reactivation of the electrode surface, E3=-0.65V. For the separation of the aminoglycosides and the internal standard of glucose, a CarboPac™ PA1 anion exchange column was used together with a mobile phase consisting of a 0.070 mol L(-1) sodium hydroxide solution in the isocratic elution mode with a flow rate of 0.8 mL min(-1). The method was validated and applied to the determination of streptomycin and dihydrostreptomycin in veterinary formulations (injection, suspension and ointment) without any previous sample pretreatment, except for the ointments, for which a liquid-liquid extraction was required before HPLC-PAD analysis. The method showed adequate selectivity, with an accuracy of 98-107% and a precision of less than 3.9%.

Er(3+)-doped silica-hafnia films for optical waveguides and spherical resonators

In this paper we present some result on sol-gel derived silica-hafnia systems. In particular we focus on fabrication, morphological and spectroscopic assessment of Er(3+)-activated thin films. Two examples of silica-hafnia-derived waveguiding glass ceramics, prepared by top-down and bottom-up techniques are reported, and the main optical properties are discussed. Finally, some properties of activated microspherical resonators, having a silica core, obtained by melting the end of a telecom fiber, coated with an Er(3+)-doped 70SiO(2)-30HfO(2) film, are presented. (C) 2009 Elsevier B.V. All rights reserved.

Comparison between a high-resolution single-stage Orbitrap and a triple quadrupole mass spectrometer for quantitative analyses of drugs.

The capabilities of a high-resolution (HR), accurate mass spectrometer (Exactive-MS) operating in full scan MS mode was investigated for the quantitative LC/MS analysis of drugs in patients' plasma samples. A mass resolution of 50,000 (FWHM) at m/z 200 and a mass extracted window of 5 ppm around the theoretical m/z of each analyte were used to construct chromatograms for quantitation. The quantitative performance of the Exactive-MS was compared with that of a triple quadrupole mass spectrometer (TQ-MS), TSQ Quantum Discovery or Quantum Ultra, operating in the conventional selected reaction monitoring (SRM) mode. The study consisted of 17 therapeutic drugs including 8 antifungal agents (anidulafungin, caspofungin, fluconazole, itraconazole, hydroxyitraconazole posaconazole, voriconazole and voriconazole-N-oxide), 4 immunosuppressants (ciclosporine, everolimus, sirolimus and tacrolimus) and 5 protein kinase inhibitors (dasatinib, imatinib, nilotinib, sorafenib and sunitinib). The quantitative results obtained with HR-MS acquisition show comparable detection specificity, assay precision, accuracy, linearity and sensitivity to SRM acquisition. Importantly, HR-MS offers several benefits over TQ-MS technology: absence of SRM optimization, time saving when changing the analysis from one MS to another, more complete information of what is in the samples and easier troubleshooting. Our work demonstrates that U/HPLC coupled to Exactive HR-MS delivers comparable results to TQ-MS in routine quantitative drug analyses. Considering the advantages of HR-MS, these results suggest that, in the near future, there should be a shift in how routine quantitative analyses of small molecules, particularly for therapeutic drugs, are performed.

Nanocharacterization of Soft Biological Samples in Shear Mode with Quartz Tuning Fork Probes

Quartz tuning forks are extremely good resonators and their use is growing in scanning probe microscopy. Nevertheless, only a few studies on soft biological samples have been reported using these probes. In this work, we present the methodology to develop and use these nanosensors to properly work with biological samples. The working principles, fabrication and experimental setup are presented. The results in the nanocharacterization of different samples in different ambients are presented by using different working modes: amplitude modulation with and without the use of a Phase-Locked Loop (PLL) and frequency modulation. Pseudomonas aeruginosa bacteria are imaged in nitrogen using amplitude modulation. Microcontact printed antibodies are imaged in buffer using amplitude modulation with a PLL. Finally, metastatic cells are imaged in air using frequency modulation.

Numerical study of reverse period doubling route from chaos to stability in a two-mode intracavity doubled Nd-YAG laser

We have numerically studied the behavior of a two-mode Nd-YAG laser with an intracavity KTP crystal. It is found that when the parameter, which is a measure of the relative orientations of the KTP crystal with respect to the Nd-YAG crystal, is varied continuously, the output intensity fluctuations change from chaotic to stable behavior through a sequence of reverse period doubling bifurcations. The graph of the intensity in the X-polarized mode against that in the Y-polarized mode shows a complex pattern in the chaotic regime. The Lyapunov exponent is calculated for the chaotic and periodic regions.

Triple photon production at the Tevatron in technicolor models

We study the process p (p) over bar --> gammagammagamma as a signal for associated photon-technipion production at the Tevatron. This is a clean signature with relatively low background. Resonant and non-resonant contributions are included and we show that technicolor models can be effectively probed in this mode. (C) 2002 Elsevier B.V. B.V. All rights reserved.