microwave electromagnetic radiation (Total 301932 Papers Found)

The history of RF and microwave computer-aided engineering is documented in the annals of the IEEE Microwave Theory and Techniques Society. The era began with elaborate analytically based models of microwave components and simple computer-aided techniques to cascade, cascode, and otherwise connect linear component models to obtain the responses of linear microwave circuits. Development has become rapid with today’s computer-oriented microwave practices addressing complex geometries and with th ...
The increasing use of expensive computer simulations in engineering places a serious computational burden on associated optimization problems. Surrogate-based optimization becomes standard practice in analyzing such expensive black-box problems. This article discusses several approaches that use surrogate models for optimization and highlights one sequential design approach in particular, namely, expected improvement. The expected improvement approach is demonstrated on two electromagnetic probl ...
A nested case-control study was used to investigate the relation between a range of electromagnetic field exposures and brain tumor risk in the US Air Force. Cumulative extremely low frequency and radiofrequency/microwave electromagnetic field potential exposures were estimated from a job-exposure matrix developed for this study. Ionizing radiation exposures were obtained from personal dosimetry records. Men who were exposed to nonionizing electromagnetic fields had a small excess risk for devel ...
A novel polarizer based on the dissolution-dynamic nuclear polarization (DNP) method has been designed, built and tested. The polarizer differs from those previously described by being designed with sterile use intent and being compatible with clinical use. The main features are: (1) an integral, disposable fluid path containing all pharmaceuticals constituting a sterile barrier, (2) a closed-cycle cryogenic system designed to eliminate consumption of liquid cryogens and (3) multi-sample polariz ...
The cost of the millimeter-wave functions in the system overall price is today one of the main limiting factor for new high frequencies applications like wide band automotive RADARs or high data rate radios. A big difficulty for the new devices above 60GHz is to be intrinsically low cost, but also to comply with simple and standard assembly techniques at the module level. This very hard challenge has already been overcome for applications below 40GHz with low cost plastic Quad Flat No-Lead packa ...
  • George C. Valley,
  • 2009 Conference on Optical Fiber Communication - incudes post deadline papers
  • 2009
Each new bit of ADC resolution requires an increase in signal-to-noise-and-distortion ratio (SNDR) of 6 dB • ENOB without noise bandwidth is meaningless • Decreasing the noise bandwidth by a factor of 4 increases ADC resolution by 1 ENOB - e.g. the Tektronix 50 GS/s digital oscilloscope has • 5 ENOB over 16 GHz • 7 ENOB over 1 GHz • Every time you sneeze, you lose a few 1/10's of an ENOB • Optical photons are very energetic compared to RF photons - Shot ...
As clock rates continue to rise, problems with signal integrity, cross-coupling, and radiation may render impractical the baseband metallic interconnects presently used in computers. A potential means to address this problem is to use bandpass wireless interconnects operating at millimeter-wave center frequencies. We have conducted experimental and finite-difference time-domain (FDTD) computational studies scaled to a 10 GHz center frequency of single-row and double-row waveguiding defects withi ...
Microwave tomography recovers images of tissue dielectric properties, which appear to be specific for breast cancer, with low-cost technology that does not present an exposure risk, suggesting the modality may be a good candidate for monitoring neoadjuvant chemotherapy. Eight patients undergoing neoadjuvant chemotherapy for locally advanced breast cancer were imaged longitudinally five to eight times during the course of treatment. At the start of therapy, regions of interest (ROIs) were identif ...
We search a sample of photometric luminous red galaxies (LRGs) measured by the Sloan Digital Sky Survey (SDSS) for a quadrupolar anisotropy in the primordial power spectrum, in which P (k) is an isotropic power spectrum P̄ (k) multiplied by a quadrupolar modulation pattern. We first place limits on the 5 coefficients of a general quadrupole anisotropy. We also consider axisymmetric quadrupoles of the form P (k) = P̄ (k){1 + g∗[(k̂ · n̂)2 − 1 3 ]} where n̂ is the axis of the anisotropy. ...
We experimentally demonstrate, for the first time, a chirped microwave pulses generator based on the processing of an incoherent optical signal by means of a nonlinear dispersive element. Different capabilities have been demonstrated such as the control of the time-bandwidth product and the frequency tuning increasing the flexibility of the generated waveform compared to coherent techniques. Moreover, the use of differential detection improves considerably the limitation over the signal-to-noise ...
It is shown that mechanical vibration (acoustical oscillation) of a solid medium along the propagation of multifrequency laser radiation enables one to control the resonant absorption. There exists an optimal spectral structure of the incident field dependent on vibration amplitude as well as the number and intensity of the frequency components that provides the full resonant transparency. A mechanism of the transparency is discussed. Transparency of this kind is shown to appear also via adiabat ...
Microwave Photonics (MWP) is a discipline which offers new opportunities to Low-Coherence Interferometry (LCI). In this paper, a novel MWP-LCI technique is presented by means of a well-established parallelism between both worlds, MWP and LCI. This technique is based on the slicing of a broadband source which is transmitted through a dispersive element. The optical path differences under test modify the electrical transfer function of the MWP-LCI subsystem through a interferometric structure. In ...
Failure of the bone-implant interface in a joint prosthesis is a main cause of implant loosening. The introduction of a bioactive substance, hydroxyapatite (HA), to a metallic bone-implant may enhance its fixation on human bone by encouraging direct bone bonding. Ti6Al4V/TiC/HA composites with a reproducible porous structure (porosity of 27% and pore size of 6-89 μm) were successfully fabricated by a rapid microwave sintering technique. This method allows the biocomposites to be fabricated in a ...
This paper reports on the stabilization of the beatnote of a dual-frequency laser on an optical fiber delay line, in a similar way as the one used for the stabilization of a microwave oscillator. This study paves the way to the realization of widely tunable, low phase noise sources of optically carried microwave signals. ...
UWB radar is superior to the conventional narrowband radar for through wall imaging applications due to its good penetration characteristics, robustness to multipath reflection, and excellent performance in severe clutter environment. A reconfigurable UWB synthetic aperture radar (SAR) was previously implemented to detect/track the real-time position of static/moving targets behind the wall [1]. In this paper, we extend this system into a 3-D imaging radar, which goes beyond targets localization ...
The design criteria for a S band Radar Beacon responding at the sole frequency of the interrogating radar are given. A microwave acoustic delay line is used to create the response of the beacon and the capability of encoding this response by a proper design of the delay line is shown. The choice of the components according to the desired characteristics is discussed. Results of laboratory and in-site tests are given, showing that such a beacon is usable in a navigational system. ...
A technique is presented for narrowing the spectral linewidth of microwave signals generated photonically by heterodyning a pair of vertical-cavity surface-emitting lasers forming an extended optically coupled cavity. The experimentally demonstrated linewidth reduction, by as much as a factor of 10(4)--to less than 10 kHz in microwave frequencies up to a couple of gigahertz--is approximately ten times that expected with conventional line-narrowing techniques such as optical feedback. An interpre ...
OBJECTIVES There are no prospective studies of laparoscopic microwave (MW) ablation in patients with hepatocellular carcinoma (HCC). The aim of this study was to demonstrate the safety and efficacy of laparoscopic MW ablation. METHODS A prospective study group of consecutive HCC patients considered ineligible for liver resection and/or percutaneous ablation was conducted from December 2009 to December 2010. Short-term (3-month) outcomes included a centralized revision of radiological response, ...
High yield and fast extraction performance ability with less solvent consumption and protection offered to thermo labile constituents are some of the attractive features of this new promising microwave-assisted extraction (MAE) technique. Therefore, MAE of gallic acid in the leaves of Eucalyptus x hybrida Maiden has been carried out and precise HPTLC method was developed for quantitative analysis of gallic acid in the leaf extracts. A range of non-polar to polar solvents were used for the MAE. A ...
Use of information and communication technology is becoming popular with time as this technology is coming with a lot of lavishness so people are demanding more of it. Electronic items have taken a status symbol in our lives. In India rich class is using up to date devices like cell phones, laptops, computers, microwave ovens, fridge, televisions etc and then pass it on to the poor class. There is no proper way for disposal or recycling of these items. This paper discuses about the increasing pr ...
Analog fiber-optic links are used in a variety of microwave applications. The RF insertion loss and RF output power available from these links is currently limited by photodetector optical power handling. Using traveling-wave concepts similar to those in distributed amplifiers, we have demonstrated traveling-wave detector arrays (TWDAs) in which photodetectors are embedded within an artificial transmission line. By feeding this network with suitably time-delayed optical signals, this arrangement ...
Summary form only given. Thermionic emission cathodes are widely used in microwave tubes. In the temperature limited (TL) region, the Richardson-Dushman equation, corrected for the Schottky effect applies. In the fully space charge limited (FSCL) region, the Child-Langmuir law applies. There were many empirical models proposed for fitting the I-V characteristics of thermionic emission cathodes. The self-consistent model has been demonstrated to be a good fit to the I-V characteristics of thermio ...
In this study, the thermal-flow characteristics of atmospheric pressure microwave CO2 plasma were numerically investigated by simulation. The electric and gas flow fields in the reaction chamber with a microwave axial injection torch operated at 2.45 GHz were simulated. The microwave launcher had the standard rectangular waveguide WR340 geometry. The simulation was performed by using the COMSOL Multiphysics plasma model with various mass flow rates of CO2. The electric fields, temperature profil ...
The rotational spectrum of a noble gas-organometallic complex was measured using a pulse molecular beam Fourier transform microwave spectrometer. Rotational transitions for the neutral argon-cyclopentadienyl thallium weakly bound complex were measured in the 4-9 GHz range. Analysis of the spectrum showed that the complex is a prolate symmetric-top rotor with C(5V) symmetry. The experimentally determined molecular parameters for Ar-C(5)H(5) (205)Tl are B=372.4479(3) MHz, D(J)=0.123(2) kHz, and D( ...
  • Wu Bi-yan, Dong Shu-rong,
  • 2006 Joint 31st International Conference on Infrared Millimeter Waves and 14th International Conference on Teraherz Electronics
  • 2006
As a high permittivity and low loss ceramic, BaO-Nd<sub>2</sub>O<sub>3</sub>-TiO<sub>3</sub> (BNT) is widely used in millimeter wave dielectric resonator. Perfect BNT thin films are obtained by through high density plasma RF sputter, and compared dielectric properties with bulk. The results show that underlay temperature has mainly effect on thin films. The optimize technology is gotten. Through simulation, thin film microstrip line based on BNT has more high ...
Innovative solutions for microwave waveguide filters have recently been developed in order to alleviate the problem of size and weight inherent to waveguide technology. Such solutions yield very compact structures along with highly selective pseudo-elliptic responses. A first class of filters is based on the ridge resonator concept, where a partial-height ridge arbitrarily located and oriented within a waveguide behaves as a quasi-TEM resonator. Depending on the position and shape of the ridge r ...
OBJECTIVE To explore the etiologic relationship between sexually transmitted diseases(STDs) and chronic prostatitis (CP), and to evaluate the effect of multiple treatment on CP following STDs. METHODS Seventy-two cases of CP after STDs were randomly divided into three groups: Group A (treated with levefloxatin), Group B (treated with Levofloxacin, terazosin and microwave), and Group C (treated with levofloxacin, Chinese traditional medicine and microwave), all treated for thirty days. The path ...
The aim of this work is to compare simultaneous isotope dilution analysis of organotin and organomercury compounds by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP/MS) on certified bivalve samples. These samples were extracted by microwave with tetramethylammonium hydroxide (TMAH). Derivatization with both NaBEt4 and NaBPr4 was evaluated, and analytical performances were compared. Two CRM materials, BCR-710 and CRM-477, w ...
In recent years, various types of medical applications of microwaves have widely been investigated and reported. In this paper, we proposed a novel coagulation device which can be used to heat up by the microwave energy and cut biological tissue by the loaded cutting blade for medical application. In addition, temperature distribution at 2.45 GHz is evaluated by FDTD method. ...
The construction of stove for food productspsila incinerating (making ash) by microwave energy at frequency of 2450 MHz is offered. The construction of irradiation structure that distributes the energy of electromagnetic field from magnetron on four equal parts is offered too. The calculation of the electromagnetic fields in a stove at given location of vessels with the explored product is conducted. ...
Multiresidue analysis of fumigants is important because of their widespread use on staple foodstuffs, such as grain. Fumigants are usually extracted from grain either by solvent extraction or by purge-and-trap techniques. In this paper, fumigant residues in wheat were "extracted" by a microwave procedure. Wheat, in gas-tight Erlenmeyer flasks, was placed in a domestic microwave oven, and fumigants were released into the headspace by microwave irradiation. Power settings for maximum release of fu ...
Abstract— In this paper we present a broadband matching technique for the design of low noise amplifiers. This technique is based on the use of coupled lines filters and quarter wave transformers for the adaptation and stabilization of these amplifiers, presenting the theory and the design process of these circuits. The type of transistors used for modeling this amplifier is the HEMT of Alpha Industries. The results we found show that this amplifier is unconditionally stable with a satisfactor ...
Pure rotational spectra of the ground vibrational states of six isotopologues of OC···AgI have been measured by chirped-pulse Fourier transform microwave spectroscopy. The spectra are assigned to determine the rotational constant, B(0), centrifugal distortion constant, D(J), and nuclear quadrupole coupling constant of the iodine atom, χ(aa)(I). The complex is linear. Isotopic substitutions at the silver, carbon, and oxygen atoms allow bond lengths to be established by the r(0), r(s), and r(m ...
The integrated nested Laplace approximation (INLA) [Rue et al., 2009] is now a well-known functional approximation algorithm for implementing Bayesian inference in latent Gaussian models but has some limitations: it is unable to handle a high dimensional model parameter θ, and makes a poor approximation when the posterior is multi-modal and the likelihood is highly nonGaussian. Two types of algorithm are proposed to address these limitations: (a) a combination of INLA and Monte Carlo methods an ...
This project aims to investigate the quality of ASCAT measurements as well as their use for oceanographic purposes. The accuracy of ASCAT retrievals will be mainly based on the use of collocated data from moored buoys, numerical weather prediction models, and satellites. The resulting collocated data will be used to explore the accuracy of the geophysical model function which relates the backscatter coefficients to surface wind vectors, as well as to assess the quality of ASCAT vector winds at g ...
AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOSHEMTs) with thick (>30 nm), high-κ (TiO<sub>2</sub>/NiO), submicron-footprint (0.4 μm) gate dielectric on SiC substrate are demonstrated, which are found to exhibit low gate leakage current (~ 1 nA/mm of gate periphery), high I<sub>MAX</sub> (1 A/mm), and high drain breakdown voltage (188 V). The derived current gain cutoff frequency is 30 GHz (from S-parameter measurements). The o ...
  • Yuriy Shlepnev,
  • 2012 IEEE 21st Conference on Electrical Performance of Electronic Packaging and Systems
  • 2012
Governing partial differential equations are derived for multiple parallel plane structure in frequency-domain. The equations can be considered as an extension of broadband equations derived earlier for one pair of planes and as an extension of well-known 2D Telegrapher's equations originally derived for analysis of narrow-band microwave planar circuits. The broadband equations have appropriate high and low frequency asymptotes and are suitable for analysis of power delivery networks (PDN) with ...
These studies indicate that the increase in the frequency of complement receptor-positive (CR+) spleen cells observed 6 days after a 30-min exposure to 2450-MHz microwaves is not the result of microwave-induced alterations of lymphocyte recirculation patterns, but is mediated by a soluble, humoral factor produced by cells within the spleen. ...
  • Zhen-tao Zhang,
  • Journal of physics. Condensed matter : an Institute of Physics journal
  • 2018
Majorana fermions are a fascinating and not yet confirmed quasiparticles in condensed matter physics. Here we propose using microwave spectra to distinguish Majorana bound states (MBSs) from topological trivial Andreev bound states. By numerically calculating the transmission and Zeeman field dependence of the many-body excitation spectrum of a 1D Josephson junction, we find that the two kinds of bound states have distinct responses to variations in the related parameters. Furthermore, the singu ...
We present in this paper the particle-in-cell simulation results of a modified axial virtual cathode oscillator having a metallic drum of radius R<sub>1</sub> placed coaxially inside the drift tube at a distance D<sub>1</sub> from the foil anode. The enlarged parameter space permits control of the current transmitted to the collection plate, the net diode current, and the size of the electromagnetic emission and extraction regions. The geometry allows low-frequency radiat ...
  • Sebastian Heller,
  • Zentralblatt fur Bakteriologie, Parasitenkunde, Infektionskrankheiten und Hygiene. Erste Abteilung Originale. Reihe A: Medizinische Mikrobiologie und Parasitologie
  • 1972
Semantic Scholar extracted view of "[Experiments on the effect of electro-magnetic waves on the reactivity of cells and tissues. 3. Effect of irradiation with red-light and microwaves on pinocytosis in FL cell cultures]." by Sebastian Heller ...
  • Da Xing,
  • 2009 Conference on Lasers & Electro Optics & The Pacific Rim Conference on Lasers and Electro-Optics
  • 2007
Laser-based photoacoustic imaging and microwave-based thermoacoustic imaging could be the next successful generation imaging techniques in biomedical application. It can provide an effective approach of tissue structure and functional images to study the architectures, physiological and pathological properties and metabolisms of biological tissues. ...
Nanodiamond has recently received considerable attention due to the various possible applications in medical field such as drug delivery and bio-labeling. For this purpose suitable and effective surface functionalization of the diamond material are required. A versatile and reproducible surface modification method of nanoscale diamond is essential for functionalization. We introduce the input of microwave energy to assist the functionalization of nanodiamond surface. The feasibility of such a pr ...
T he idea of a frequency comb seems relatively simple, yet substantial technical efforts are required for one to be generated with the high accuracy and stability needed for metrology applications. The ideal frequency comb would be a set of discrete equidistant frequency (f) components separated by intervals ∆f. Typically ∆f is in the microwave range so that the separation of the comb “teeth” can be measured and controlled electronically. However, stabilization of ∆f is not sufficient ...
The reaction of the dimer [Rh(III)(pentamethylcyclopentadienyl)(μ-Cl)Cl]2 ([Rh(III)(Cp*)(μ-Cl)Cl]2) with the hydroxypyrone ligands maltol and allomaltol affords complexes of the general formula [Rh(III)(Cp*)(L)Cl] under standard and microwave conditions. The organometallic compounds were characterized by standard analytical methods and in the case of the allomaltol derivative in the solid state by single-crystal X-ray diffraction analysis. The complexes showed similar cytotoxicity profiles and ...
The mechanical size reduction of solids is an energy intensive and highly inefficient process. Therefore, there is great incentive to improve the efficiency of size reduction and mineral separation processes. Over several decades, this has promoted significant amounts of research,unfortunately, this has only led to small, incremental improvements in efficiency. One area which has shown significant promise for improving the efficiency of mineral comminution and separation processes is microwave a ...
This paper presents a novel optimization technique that combines classical and statistical methods in an innovative and efficient way. In specific, an evolutionary genetic algorithm (GA) has been developed that utilizes a local minimization scheme based on the method of conjugate directions. The proposed optimizer has been applied to the design of planar microwave circuits and printed antenna arrays. The advantages of the proposed technique are illustrated by ample numerical results. ...
Experiments have been carried out on the curing of poly(methyl methacrylate) denture base material in a microwave oven, using conventional dental flasks and flask clamps. It has been shown that it is important (a) to maintain sufficient pressure on the materials, (b) to avoid gaseous porosity by not heating too rapidly initially, and (c) to ensure that all metal is protected from exposure to microwaves. When the appropriate conditions of polymerisation were used, microwave-cured samples had sa ...
New interferometric frequency discriminators (FD) for frequency stabilization of microwave oscillators are examined. Alternative topologies to the standard interferometric readout are presented. The new readouts are arranged in a bi-directional configuration. In this configuration, microwaves pass in both directions through each arm of the interferometer. The coupling to the resonator is adjusted to maximize the frequency discriminator sensitivity. The sensitivity is compared with that for the c ...