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Ceramic/polymer nanocomposites have been extensively explored for dielectric capacitor application due to their high energy storage performance and ease of processing, flexibility, and low cost. However, improving compatibility between inorganic and organic materials is of great significance and has been a long-standing challenge. In this work, the polymer surfactant Pluronic[TM] F127 was employed to perform surface modification of Ba[TiO.sub.3] through a facile solution process. The compatibility between Ba[TiO.sub.3] nanoparticles and P (VDF-HFP) can be remarkably strengthened by the affinity between F127 polymer chains and the organic matrix. Structural defects such as pores, cracks, and agglomeration of inorganic particles were obviously reduced, and interfacial polarization has been significantly enhanced. The discharged energy density [U.sub.d] and charge-discharge efficiency [eta] reach up to 5.0J/[cm.sup.3] and 58.1% under the breakdown strength of 3740 kV/cm for the nanocomposite containing 1 vol% BT@F127. These dielectric properties are clearly better than the nanocomposite using unmodified BT, as well as similar hybrids reported previously. KEYWORDS ceramic/polymer nanocomposite, dielectric property, energy density, surface modification, 1 | INTRODUCTION Dielectric capacitors are the basic components of energy storage in modem electronic and electrical systems. They have been widely used in the fields of power transmission, hybrid [...]

In this work the synthesis and characterization of an organic-inorganic hybrid composite film based on hafnium oxide (Hf[O.sub.2]) and polyvinylpyrrolidone (PVP) with dielectric properties is presented. These films were prepared using the sol-gel process adjusting the chemical composition to tailor the material properties, such as the dielectric and the optical band gap. The Hf[O.sub.2] was obtained by the hydrolysis of hafnium chloride (Hf[Cl.sub.4]) under catalysis of ethanol and deionized water, later the PVP was subsequently added to complete the hydrolysis. Finally the films were dried at 150°C. The structural characterization of the hybrid material showed a hafnium nanoparticle size around 100 nm into the polymer matrix. The chemical structure and the high purity of the hybrid material were corroborated by X-ray photoelectron spectroscopy measurements, which showed the bounding of Hf[O.sub.2]-PVP. The electrical characterization demonstrated that the nanostructured materials with hafnium nanoparticles improve the dielectric constant in the films with values around k = 18.5. The optical band gap, [E.sub.ο], was obtained from 4 to 5.7 eV. These characteristics in our hybrid material are very promising for flexible electronics applications with the advantage of its low temperature, thermal stability, and low cost process of deposition. PACS Nos.: 81.15.-z, 81.07.Pr, 77.55.-g. Nous presentons ici la synthese et la caracterisation de films composites hybrides organiques-inorganiques, bases sur l'oxyde de hafnium (Hf[O.sub.2]) et de polyvinylpyrrolidone (PVP) avec des proprietes dielectriques. Ces films sont prepares par procede sol-gel en ajustant la composition chimique afin de tailler sur mesures les proprietes du materiau, comme la constante dielectrique et le gap optique. Nous obtenons le Hf[O.sub.2] par hydrolyse du chlorure d'hafnium (Hf[Cl.sub.4]) sous catalyse d'ethanol et d'eau de-ionise, apres quoi, le PVP est ajoute pour completer l'hydrolyse. Finalement, les films sont seches a 150°C. La caracterisation de la structure du materiau hybride montre une nanoparticule de hafnium de 100 nm dans la matrice de polymere. La structure chimique et la haute purete du materiau hybride sont corroborees par spectrometrie photoelectrique X, qui montre la liaison Hf[O.sub.2]-PVP. La caracterisation electrique demontre que le materiau nanostructure avec nanoparticule de hafnium ameliore la constante dielectrique dans les films autour de k = 18.5. La bande interdite optique [E.sub.ο] est entre 4 et 5.7 eV. Ces caracteristique de notre materiau hybride sont tres prometteuses pour des applications electroniques flexibles, avec l'avantage de sa basse temperature, de sa stabilite thermique et son bas cout de deposition. [Traduit par la Redaction], 1. Introduction Currently the research for alternative materials in the fabrication of flexible and low-cost electronics has been focused on the development of the thin films at low-temperature and large-area [...]

The efficacy of a single dielectric barrier discharge plasma actuator for controlling turbulent boundary-layer separation from the deflected flap of a high-lift airfoil is investigated between Reynolds numbers of 240,000 (15 m/s) and 750,000 (45 m/s). Momentum coefficients for the dielectric barrier discharge plasma actuator are approximately an order of magnitude lower than those usually employed for such studies, yet control authority is still realized through amplification of natural vortex shedding from the flap shoulder, which promotes momentum transfer between the freestream and separated region. This increases dynamic loading on the flap and further organizes turbulent fluctuations in the wake. The measured lift enhancement is primarily due to upstream effects from increased circulation around the entire model, rather than full reattachment to the deflected flap surface. Lift enhancement via instability amplification is found to be relatively insensitive to changes in angle of attack, provided that the separation location and underlying dynamics do not change. The modulation waveform used to excite low- frequency perturbations with a high-frequency plasma-carrier signal has a considerable effect on the actuator performance. Control authority decreases with increasing Reynolds number and flap deflection, highlighting the necessity for further improvement of plasma actuators for use in realistic takeoff and landing transport aircraft applications. These findings are compared to studies on a similar high-lift platform using piezoelectric-driven zero- net-mass flux actuation. DOI: 10.2514/1.J050452

Nano-electromachining (nano-EM) is a process in which electric fields applied across sub-20 nm tool-workpiece gaps in organic dielectrics (n-decane [C.sub.10][H.sub.22] and n-undecane [C.sub.12][H.sub.26]) are used to produce nanometer size features (8-80 nm) in electrically conductive materials. In order to improve the speed of nano-EM for manufacturing, utilization of pulse breakdown phenomena is studied. Linear behavior of Paschen curves for pulse breakdown demonstrated the predictability of pulse nano-EM process. The discharge current in the machining gap showed exponential decay behavior in the post-breakdown regime with certain delay. This delay in current recovery may present a limit to improving nano-EM production speeds' and suggests a need for external pressurized dielectric flow over self-guided diffusion. Other notable effects such as adsorption compression limited dielectric diffusion and the variation in the recovery current with the tool-workpiece gap along with their engineering implications are discussed. [DOI: 10.1115/1.4001718]

In this study, a new technique for detecting ungrouted cells in concrete block masonry constructions was developed. The concept, based on detecting the local dielectric permittivity variations, was employed to design coplanar capacitance sensors with high sensitivities to detect such construction defects. An analytical model and finite element simulations were used to assess the influence of the sensor geometrical parameters on the sensor signals and to optimize the sensor design. To experimentally verify the model, the dielectric properties of various materials involved in concrete masonry walls were measured. In addition, a masonry wall containing predetermined grouted and ungrouted cells was constructed and inspected using the developed sensors in a laboratory setting. Moreover, different capacitance sensors were designed and compared with respect to their sensitivity, signal-to-noise ratio, and coefficient of variation of the inspected measurements. Excellent agreements were found between the experimental capacitance signal response parameters and those predicted by the analytical and finite element models. The proposed sensor design, coupled with a commercially available portable capacitance meter, would facilitate employing this technique in the field for rapid inspection of masonry structures without the need for sophisticated data analyses usually required by other more expensive and time consuming methods. DOI: 10.1061/(ASCE)EM.1943-7889.0000085 CE Database subject headings: Walls Masonry; Grouting; Probe instruments; Damage; Measurement; Nondestructive tests; Concrete construction. Author keywords: Walls; Masonry; Grouting; Sensors: Damage; Measurement; Nondestructive tests.

Much experience has been gained with the use of the dielectric methods in granular or fine-grained soil with low to medium plasticity. Empirical equations were proposed to describe the relationship between water content and measured bulk dielectric constant of the soils. However, the proposed empirical equations are generally not considered applicable for highly plastic, expansive soils due to factors such as bound water and high electric conductivity. This paper presents calibration equations for various commercially available dielectric-based probes. The calibration curves have been determined through laboratory calibration using compacted specimens. The differences between the calibration curves and those predicted by the empirical equations, as well as those provided by the manufacturer, are assessed and discussed. The effect of temperature on the response of the probes was also studied. Key words: water content measurement, dielectric-based probe, time-domain reflectometry, calibration, expansive soil, unsaturated soil. Beaucoup d'expeerience a ete obtenue dans le passe a propos de l'utilisation des methodes dielectriques dans des sols granulaires ou fins avec une plasticite faible a moyenne. Des equations empiriques ont ete proposees pour deecrire la relation entre la teneur en eau et la constante dielectrique apparente des sols. Cependant, les equations empiriques proposees ne sont geeneralement pas considerees comme applicables pour des sols expansifs a plasticite; elevee en raison de differents facteurs tels que l'eau liee et la conductivite electrique elevee. Cet article presente des equations de calibrage pour plusieurs sondes basees sur les proprieties dielectriques disponibles sur le marche. Les courbes de calibrage ont ete determinees par des calibrages en laboratoire sur des echantillons compacteis. Les differences entre les courbes de calibrage obtenues en laboratoire et celles predites par les equations empiriques, ainsi que celles fournies par le manufacturier, sont evalueies et discutees. L'effet de la temperature sur les domtoes obtenues a l'aide des sondes a aussi ete etudie. Mots-cles: mesure de la teneur en eau, sonde basee sur les proprietes dielectriques, reflectometrie dans le domaine temps, calibrage, sol expansif, sol non sature. [Traduit par la Redaction], Introduction Due to the high percentage of swelling clay minerals in expansive soils, they exhibit high swelling or expansion when wetted. As a result of volume changes, lightly loaded structures [...]

We describe a novel artificial dielectric material that has applications at millimeter and submillimeter wavelengths. The material is manufactured from layers of metal mesh patterned onto thin polypropylene sheets, which are then bonded together using a hot pressing process to provide planar rugged discs that can be reliably cycled to cryogenic temperatures. The refractive index of this material can be tuned by adjusting the geometry and spacing of the metal mesh layers. We demonstrate its usage by designing and characterizing a broadband antireflection coating for a Z-cut crystalline quartz plate. The coating was fabricated and applied to the quartz using the hot press technique and characterized using a Fourier transform spectrometer. The performance is shown to be in good agreement with a high frequency structure simulator and transmission line modeling results. OCIS codes: 160.3918, 160.4670.

In this paper, the deposition and characterization of plasma-polymerized polystyrene (pp-PS) using PECVD under atmospheric pressure on a variety of substrates was investigated. An atmospheric RF plasma torch and an HF dielectric-barrier-discharge (DBD) system were used to deposit thin pp-PS coatings on PTFE, HDPE, stainless steel, glass, and silicon wafer. The styrene vapor was carried by Ar or He. The pp-PS films were characterized by Fourier transform infrared spectroscopy (FTIR) (infrared reflection absorption spectroscopy), X-ray photoelectron spectroscopy (XPS), water contact angle (WCA), static secondary ion mass spectroscopy (SSIMS), and optical microscopy, and the plasma phase was studied by optical-emission spectroscopy. The major features that characterize PS are present in the FTIR, SSIMS, and XPS spectra of our films, although some differences are observed between pp-PS and their conventionally polymerized counterparts: oxygenation, branching, degree of cross-linking, and unsaturation. According to the WCA and XPS results, the films deposited by the RF plasma torch (placed in a Plexiglass chamber) are more oxygenated than those deposited by DBD, which is operated under a much more controlled atmosphere. A comparison of the chemical structure of the deposited coatings (branching, cross-linking) as a function of the nature of the carrier gas was established by FTIR: pp-PS synthesized in the presence of Ar (for both processes) exhibit more branching and a higher degree of cross-linking than pp-PS synthesized with He as the main plasma gas. The optical microscopy points out a diversity of structures that depend on the nature of the substrate and the plasma parameters. Index Terms--Plasma CVD, plasma materials-processing applications, plasmas, plastics.

This paper presents results on surface processing of polymeric materials using a particular plasma reactor configuration. An atmospheric-pressure plasma beam is used to create a surface discharge with an axially symmetric profile. The exposure to He and mixtures of He with reactive gases allows combined functionalization and cross linking on polymers in film and fiber forms. Index Terms--Atmospheric-pressure plasma, cross linking, dielectric barrier discharge (DBD), functionalization, polymer.

A transmission-type surface plasmon resonance configuration with dielectric gratings regularly patterned on a silver film was investigated with the aim of enhancing the diffraction efficiency of radiative surface plasmons. The theoretical work was conducted using rigorous coupled-wave analysis in terms of first order diffraction efficiency and conversion efficiency (CE). The results show that pyramid gratings can produce a higher transmittance compared with other grating profiles. Design optimization of the pyramid grating at a wide range of grating thicknesses and periods resulted in a maximum transmittance that was larger than 77% and a peak CE of about 85%. This study demonstrates the potential of using transmitted surface plasmon waves in various optical devices, such as optical biosensors, optical imaging systems, and polarization filters. OCIS codes: 050.2770, 240.6680, 310.0310.

A novel coupling technique for circularly polarized square-ring patch antenna is developed and discussed. The circular polarization (CP) radiation of the square-ring patch antenna is achieved by a simple microstrip feed line through the coupling of a square patch on the same plane of the antenna. Proper positioning of the coupling square patch excites two orthogonal resonant modes with 90[degrees] phase difference, and a pure circular polarization is obtained. The dielectric material is a square block of ceramic with a permittivity of 58 and that reduces the size of the antenna. The prototype has been designed, fabricated and found to have an impedance bandwidth of 1.1% and a 3-dB axial-ratio bandwidth of about 0.03 % at GPS frequency of 1573 MHz. The characteristics of the proposed antenna have been studied by simulation software HFSS and experiments. The measured and simulated results are in good agreement. Index Terms--Ceramic dielectric material, circular polarization (CP), global position system (GPS), square-ring patch antenna.

This paper is a study of a plasma actuator in the absence of external flow by means of particle image velocimetry measurements. The properties of the electric wind produced by the actuator are investigated by spatially resolved and phase-locked measurements. The use of a particle image velocimetry apparatus is of great interest to accurately examine the spatio-temporal history of the electric wind formation. The approach consists of evaluating the time required by the induced airflow to reach a stationary state and also in describing the different states of its formation. The electric wind is generated by a single dielectric barrier discharge excited by a sine waveform of 1 kHz, having an amplitude of 20 kV. Turbulent kinetic energy, swirl strength, pure shear flow and mass flow rate are also used to describe the formation process of the airflow. Index Terms--Plasma actuator, dielectric barrier discharge, electric wind, particle image velocimetry.

In power electronics applications, power cables spread paths of conducted disturbances throughout the system. This paper proposes a high frequency modeling method for power cables that takes into account phenomena which appear when the switching frequency of the static converter increases, such as skin effects, proximity effects and dielectric losses. The proposed power cable models are obtained by the series-association of n identical RLCG basic cells. The skin and proximity effects are represented as the impedance of an R-L ladder and the dielectric losses as the admittance of an R-C ladder. The proposed method was successfully applied to a three-wire unshielded cable and extended to a four-wire shielded cable. Index Terms--Power cables, skin effect, dielectric losses, multiconductor transmission lines, circuit, frequency domain analysis.

Effective area of guarded electrode is always larger than its geometrical area as a result of fringing effect. In most standards concerning permittivity and volume resistivity measurements, an increase in the effective fringing is assumed as a half of the width of the gap between the guarded electrode and the guard electrode (then the factor B = 1). In some standards, the increase calculated from Amey relation, is assumed to be smaller (B < 1). The Amey relation is exact only for sample permittivity [epsilon] [right arrow] [infinity]. It is correct to apply the relation to calculate the volume resistivity, but it is incorrect to use it to calculate the permittivity of a sample. In this paper, a proper relation for the factor B has been derived analytically for thin electrodes made usually by thin film technology. The factor B can be used to calculate the permittivity of samples with arbitrary value of 8. Appropriate changes into the standard IEC 60250 and into other standards concerning permittivity measurements are proposed. Index Terms--Dielectric materials, permittivity, resistivity, measurement, electrodes, standardization.

A hybrid method that combines method of moments (MOM) and cylindrical eigenfunction expansion is presented to study a substrate integrated waveguide circuit that consists of metallic and dielectric circular cylinders. The problem is considered as a 2-D electromagnetic problem assuming no field variation normal to the dielectric substrate. The scattered field from each circular cylinder is expanded by cylindrical eigenfunctions, and the equivalent current densities at a waveguide port are expanded using the MOM. After enforcing boundary conditions and applying the additional theorem of Bessel and Hankel functions, a set of linear equations are constructed using the orthogonality of the exponential function. With matrix manipulation and sub-ports combination, the S matrix can then be obtained. Four examples are analyzed by using the hybrid method and verified by using Ansoft Corporation's commercial High Frequency Structure Simulator (HFSS) software package. It is shown that the hybrid method runs faster than HFSS and requires less memory. It is also pointed out that the method can be used to study a circuit with noncircular cylinders. Index Terms--Eigenfunction expansion, method of moments (MOM), substrate integrated waveguide.

We point out an important fundamental limitation associated with the dielectric ribbon waveguide described by Yeh et al. [Appl. Opt. 44, 5937 (2005)], which would restrict its practical use in ultrahigh- or terahertz-speed guided-wave applications, contrary to their underlying prediction, and we additionally point out a noteworthy inaccuracy in their introductory discussion. OCIS codes: 230.7390, 320.5390, 350.4010, 320.5550, 350.5500.

Bragg grating structures based on dielectric slot waveguide are studied. Findings reveal the existence of optimum widths from the high-index cladding.

Periodic structures can help in the reduction of mutual coupling by using their capability of suppressing surface waves propagation in a given frequency range. The purpose of this work is to show the viability of using a planar electromagnetic band gap (EBG) structure based on a truncated frequency selective surface (FSS) grounded slab to this aim. The goal is to use it in patch antenna arrays, keeping both the element separation smaller than [[lambda].sub.0] for grating lobes avoidance (assuming broadside case) and the patch antenna size large enough to have a good antenna directivity. To this aim, a multilayer dielectric substrate composed of high and low permittivity layers is convenient. This allows the use of a planar EBG structure made of small elements printed on the high permittivity material and, at the same time, the low permittivity layer helps the bandwidth and the directivity of the antenna to be increased. The EBG structure was designed under these premises and optimized for the particular application via an external optimization algorithm based on evolutionary computation: ant colony optimization (ACO). The mutual coupling reduction has been measured and it is larger than 10 dB with a completely planar structure. Index Terms--Ant colony optimization (ACO), electromagnetic band gap (EBG), multilayer substrate, mutual coupling, patch antenna array, periodic structure.

An enhanced iterative method for the precise reconstruction of piezoelectric material parameters from electric impedance and mechanical displacement measurements is described. The method is based on combination of finite-element simulations of the full three-dimensional piezoelectric equations and Newton or nonlinear Landweber iterative inversion scheme.

This paper provides an overview of the physics and design of single dielectric barrier discharge (SDBD) plasma actuators for enhanced aerodynamics in a variety of applications. The actuators consist of two electrodes, one exposed to the air and the other covered by a dielectric material. The electrodes are supplied with an ac voltage that at high enough levels, causes the air over the covered electrode to ionize, The ionization of the air is a dynamic process within the ac cycle. The ionized air, in the presence of the electric field produced by the electrode geometry, results in a body force vector that acts on the ambient air. The body force is the mechanism for active aerodynamic control. The body force per unit volume of plasma has been derived from first principles and implemented in numerical flow simulations. This utilizes models for the time and space dependence of the air ionization on the input voltage amplitude, frequency, electrode geometry and dielectric properties that have been developed and bench-marked with experiments. The experiments and model suggest approaches that can maximize the performance of the plasma actuators. A sample implementation of an actuator model in a numerical flow simulation consisting of leading-edge separation control on an airfoil along with an experimental benchmark is then presented.

The study results of the dual-material-gate (DMG) insulated shallow extension gate-stack MOSFET involving dielectric pocket (DP) and DMG assimilation onto the conventional MOSFET, which reveal a reduction in substrate leakage current, is presented.

Subwavelength metallic and dielectric diffraction gratings which rotate the linear polarization of incident light by 90[degrees] are examined. Using rigorous diffraction theory in total-internal-reflection configuration, it is shown that full conversion from incident transverse electric field to transverse magnetic zero-order field can be achieved with both dielectric and metallic elements, but dielectric gratings provide higher efficiency and are thus preferable. The fabrication aspects and constraints are discussed in detail and the behavior of the gratings over broad wavelength bands is presented. OCIS codes: 230.1950, 260.2110, 260.5430.

Atmospheric pressure dielectric barrier discharge (DBD) plasma can be used to split low molecular weight organic compounds, and the DBD-split/excited species can be swept into luminol solution to induce chemiluminescence (CL) emission. Based on this observation, a novel optical detector was proposed and preliminarily tested as a potential gas chromatographic (GC) detector in this work. The advantages of this new type of detector include the following: direct detection, fast response, high sensitivity, versatility (sensitive to a broad range of volatile organic compounds), simple and easy instrumentation, compactness (3.0 mm i.d. x 4.0 mm o.d. x 20 mm length of the DBD device), and low power (less than 5 W). Twelve volatile organic compounds, including methanol, ethanol, propanol, formaldehyde, acetaldehyde, benzene, dichloromethane, trichloromethane, tetrachloromethane, tetrahydrofuran, carbon bisulfide, and ethyl ether, were tested with this detector, and each of them produced a large signal. It was found that the CL signal was proportional to the analyte concentration and affected by the DBD parameters. Under the optimized experimental conditions, the limits of detection down to the tens of nanogram level were achieved for methanol, ethanol, propanol, formaldehyde, and acetaldehyde. It was then preliminarily tested as a GC detector for the separation of formaldehyde, ethanol, and propanol. This is the new application of DBD in analytical chemistry, and CL was for the first time generated in this way. The new detector can be a potential GC detector suitable for a wide range of volatile organic compounds.

In this paper, the design, fabrication, and measurement of reliable low-cost capacitive radio-frequency microelectromechanical systems switches with a novel fabrication approach using direct photodefinable high-k metal oxides are presented. In this approach, a radiation-sensitive metal-organic precursor is deposited via spin coating and converted to a high-k metal oxide via ultraviolet exposure. Measurements of the bridge-type switches have been done up to 40 GHz. These switches are reliable (> 340 million cycles) and exhibited low insertion loss (about 0.3 dB at 20 GHz) and better isolation (about 24 dB at 20 GHz) at frequencies below the resonant frequency as compared to switches that are fabricated using a simple silicon nitride dielectric. [2006-0144] Index Terms--Metal-oxide dielectrics, photodefinable, radio-frequency (RF) microelectromechanical systems (MEMS) switch, reliable.

Based on a Marx generator and a coaxial pulse forming line, an experimental investigation of surface flashover characteristics in vacuum is conducted by using nanosecond pulses of 10 ns rise time and 30 ns full width at half maximum (FWHM). Insulator dielectrics chosen for this investigation are Teflon, PMMA and Nylon. The tested factors include gas pressure, cone angle of conical frustum, diameter and length of cylindrical insulator, material and shape of electrode, and contact style between insulator and electrodes. The effects of these parameters on the surface flashover characteristics are described and analyzed in this paper. In addition, the character of flashover time lag in the nanosecond range, and surface flashover theory in vacuum charged by nanosecond pulses are also discussed. Index Terms--Surface flashover, vacuum, nanosecond pulse, cathode triple junction, electron emission.

The multilevel fast multipole algorithm (MLFMA) is very efficient for solving large-scale electromagnetic scattering problems. However, at low frequencies, or when the discretization is small compared with the wavelength, both the MLFMA and the underlying integral equation formulation typically suffer from a subwavelength breakdown. For the electromagnetic scattering from a homogeneous dielectric object, we obtain a stable and well-conditioned surface integral formulation using a variant of the classical Muller formulation and linear basis functions. To overcome the subwavelength breakdown of the MLFMA, we use both propagating and evanescent plane waves to represent the fields. The implementation is based on a combination of the spectral representation of the Green's function and Rokhlin's translation formula. We also present a new interpolation scheme for the evanescent part, which significantly improves the error-controllability of the MLFMA-implementation. Several numerical results verify both the error-controllability and scalability of the proposed algorithm. Index Terms--Boundary integral equations, dielectric bodies, electromagnetic scattering, fast solvers, subwavelength breakdown.

We show how the design of integrated arrays can significantly benefit from planar circularly symmetric (PCS) electromagnetic band gap (EBG) structures. Using this technology, a phased array that scans up to 40[degrees] in one dimension and that is characterized by relatively large bandwidth (BW [approximately equal to] 15%) is designed, manufactured and tested. The specific advantages coming from the use of PCS-EBGs are two fold. On one hand the losses associated to surface waves are significantly reduced. On the other hand each element of the array has a larger effective area that leads to a higher gain for the complete array when compared with a standard technology. Additional benefits are the low cross-polarization levels, the good front to back ratio considering that the antenna does not include a backing reflector, and the low profile. Index Terms--Electromagnetic band gap (EBG), phased arrays, printed technology, surface waves.

Memory errors can occur in the stages of a pipelined analog-to-digital converter (ADC) due to several effects. These include capacitor dielectric absorption/relaxation, incomplete stage reset at high clock rates, and parasitic capacitance effects when opamps are shared between subsequent pipeline stages. This paper describes these sources of memory errors and the effect they have on overall ADC linearity. It is shown how these errors relate to and differ from interstage gain errors. Two new calibration algorithms are proposed that correct for memory errors by digital post-processing of the ADC output. Both algorithms operate in the background and so do not require conversion to be interrupted in order to track changes due to temperature and supply variations. The two algorithms are compared in terms of their system costs and their dependence on input signal statistics. Index Terms--Analog-to-digital converter (ADC), calibration, dielectric materials, switched capacitor circuits.