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Inductors
Kinds of Inductors Selected AbstractsIntegrated inductors on porous siliconPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2007H. Contopanagos The cover picture illustrates the effective use of a thick porous silicon layer as an integrated micro-plate for RF isolation on a silicon substrate, proposed by Harry Contopanagos and Androula Nassiopoulou in their Original Paper [1] in the current issue. What is plotted is the magnitude of the current distribution (colour coded from blue (low) to high (red) values) on the metallization and on a screen 50 µm underneath the bottom oxide layer of a 2-metal integrated CMOS-compatible inductor on bulk silicon (lower right) and on a 50 µm thick porous silicon layer (upper left) for a frequency of 2.5 GHz. Inductors were designed in a standard 0.13 µm CMOS technology. Efficient RF isolation is produced by the porous Si layer, as evidenced by the virtual elimination of surface currents relative to the case of standard CMOS, indicating virtually complete substrate shielding by a 50 µm thick porous Si layer for the relevant size scale. The quality factor of the inductor with the use of the porous Si layer is increased by 100%, reaching a maximum value of 33 for the design shown. The first author of the article is a visiting senior researcher at the Institute of Microelectronics (IMEL), National Center for Scientific Research "Demokritos" (Athens, Greece). His research focuses on electromagnetics and microwave engineering, artificial materials and photonic crystals, wireless front ends, antennas and high-frequency analog integrated circuits. [source] ChemInform Abstract: Diastereoselective Alkylation of Acetoacetates of Chiral Inductors.CHEMINFORM, Issue 4 2001Synthetic Applications. Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Development of a 3-dimensional LIGA process and application to fabricate a spiral microcoilELECTRICAL ENGINEERING IN JAPAN, Issue 1 2009Harutaka Mekaru Abstract LIGA process has been developed in the 2.5-dimensional world. We introduced new technologies of a 3D X-ray lithography and a worm injection molding with an unscrewing de-molding mechanism, and succeeded in the deployment of a 3D LIGA process. Furthermore, we fabricated a spiral microcoil using the 3D-LIGA process and a metallization technique combining flat and smooth electroplating and isotropic chemical etching. The microcoil diameter was 0.5 mm and the length was 1 mm. The width of coil lines was 10µm and the pitch was 20µm. Characteristics of this microcoil as an inductor combine the inductance of 91 nH and the quality factor of 5.8 at the frequency of 1 GHz. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(1): 43,51, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20679 [source] An Efficient Asymmetric Synthesis of 2-Substituted 1,4-Benzodiazepin-3-one as a Potential Molecular ScaffoldEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2005Nuria Cabedo Abstract 2-Substituted 1,4-benzodiazepine-2-one compounds (9,12) were obtained by a highly diastereoselective alkylation of a seven-membered ring benzolactam (8) in the presence of (R)-phenylglycinol as a chiral inductor. The corresponding acid derivative (16) afforded a conformationally constrained structure suitable for preparing peptidomimetic analogues useful as a novel molecular scaffold. After cleavage of the chiral appendage this approach might also lead efficiently to enantiomerically pure 2-substituted benzodiazepines (15). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Design and implementation of an interleaved soft-switching converter with output voltage doublerINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 2 2010B.-R. Lin Abstract An interleaved pulse-width modulation (PWM) converter with less power switches is presented in this paper. The buck type of active clamp circuit is used to recycle the energy stored in the leakage inductor of a transformer. The zero voltage switching (ZVS) turn-on of power switches is realized by the resonance during the transition interval of power switches. At the secondary side of transformers, two full-wave rectifiers with dual-output configuration are connected in parallel to reduce the current stresses of the secondary windings of transformers. In the proposed converter, power switches can accomplish two functions of the interleaved PWM modulation and active clamp feature at the same time. Therefore, the circuit components in the proposed converter are less than that of the conventional interleaved ZVS forward converter. The operation principle and system analysis of the proposed converter are provided in detail. Experimental results for a 280,W prototype operated at 100,kHz are provided to demonstrate the effectiveness of the proposed converter. Copyright © 2008 John Wiley & Sons, Ltd. [source] LC-active VCO for CMOS RF transceiversINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 1 2010Domenico Zito Abstract A novel fully integrated CMOS LC tank VCO is presented. The LC tanks are implemented by exploiting the active circuit ,boot-strapped inductor' (BSI), which behaves like a high-quality factor inductor. Particularly, the LC tanks have been implemented by introducing a new version of the CMOS BSI circuit, which provides better versatility and design reliability. In order to verify the effectiveness of such an approach, a case study for 5,6,GHz direct-conversion multi-standard WLAN transceivers is presented. The VCO has been designed in a 0.35µm standard CMOS technology. The new BSI exhibits a high-quality factor (higher than 25 over the all frequency range) and provides a high selectivity without introducing a relevant excess of noise, for a better spectral purity and a lower phase noise (PN) of the VCO. The overall VCO circuit consumes 9,mW. The VCO produces an oscillation in the tuning range from 4.91 to 5.93,GHz (nearly equal to 19%). The circuit exhibits a PN of ,129dBc/Hz at 1,MHz of frequency offset from the central frequency (5.4,GHz) and a FOM equal to 189.5,dBc/Hz at 100,kHz and 194.1,dBc/Hz at 1,MHz of frequency offset, respectively. Copyright © 2009 John Wiley & Sons, Ltd. [source] An approach for the calculation of magnetic field within square spiral inductors at low frequencyINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 4 2002Noureddin M. Ibrahim Abstract The magnetic field distribution within a square spiral inductor is investigated in this paper by summing closed-form expressions for the fields from each segment. Plots illustrating the variation of the normally directed B -field penetrating the surface of the spiral traces are then developed for a variety of perspectives. The expressions and insight gained represent an essential step in developing a detailed model of effects such as current crowding, which significantly limit the spiral's performance in practical circuits. Copyright © 2002 John Wiley & Sons, Ltd. [source] Modeling and synthesis of the interdigital/stub composite right/left-handed artificial transmission lineINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2009R. Siragusa Abstract An efficient design procedure, including both analysis and synthesis, is proposed for Composite Right/Left Handed (CRLH) interdigital/stub structures. Improved models are developed for both the interdigital capacitor and the shorted stub inductor including its ground via hole. Subsequent optimal formulas are recommended to model these components with their parasitic effects. The models and formulas are verified by both full-wave and experimental results. A CAD program with a friendly GUI, available online, is provided and its operation is described in details. This program allows a very fast design of the CRLH structure, and its synthesis parameters are proven very accurate without any full-wave optimization. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009. [source] Efficient inductance calculation for planar spiral inductors and transformers based on analytical concentric half-turn formulasINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 6 2006Wei Gao Abstract A new method to efficiently calculate the self and mutual inductances of a planar spiral inductor or a multicoil transformer is presented. Three analytical formulas are firstly derived to calculate partial inductances of concentric half-turn segments, which are then summed to the device's total inductances. The final results are quite accurate whether compared to the measurements or the numerical simulations. The method is also compatible with any script-supported circuit simulators. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2006. [source] Immune-expression of HSP27 and IL-10 in recurrent aphthous ulcerationJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 8 2008Nelson T. Miyamoto Jr Background:, Recently, abnormal cellular immune response has been considered responsible for the oral lesion in the recurrent aphthous ulceration (RAU). For reasons not yet defined, antigens of the oral microbiota would trigger abnormal Th1 immune response against epithelial cells. On the other hand, studies have demonstrated that heat shock proteins (HSP) can block the production of proinflammatory cytokine through inhibition of NF-,B and mitogen-activated protein kinase pathways or activate anti-inflammatory cytokines and therefore control the magnitude of the immune response. HSP27 has been considered a powerful inductor of IL-10, a major inhibitor of Th1 response. Methods:, Using immunohistochemistry, we studied the expression and location of HSP27 and IL-10 in ulcerated lesions clinically diagnosed as RAU (n = 27) and to compare it with that of oral clinically normal mucosa (CT; n = 6) and of other inflammatory chronic diseases such as oral fibrous inflammatory hyperplasia (FIH; n = 18), Crohn's disease (CD; n = 10) and ulcerative colitis (UC; n = 9). Results:, A lower proportion of HSP27-positive epithelial cells in RAU and CD were observed when compared with CT and FIH (P < 0.001**; P = 0.013**). A lower proportion of IL-10-positive interstitial cells in RAU was observed when compared with FIH, UC, CT and CD (P < 0.001**; P < 0.001**; P < 0.001**; P = 0.034*). Conclusion:, Altogether the data suggest that a reduced cellular expression of HSP27 and IL-10 in RAU might be related with the aetiopathogenesis of the ulcerated oral lesions. [source] Microwave Bandgap in Multilayer Ceramic StructuresJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2006Bo Li A multilayer ceramic structure with a photonic bandgap (MC-PBG) was fabricated by a method of tape casting combined with screen printing. The MC-PBG structure is a two-dimensional array with either rectangular or hexagonal metal coils in a ceramic matrix. The metal coils are connected to the base metal layer in the ceramic substrate to form a monolithic body. The surface-wave dispersion properties of these MC-PBG structures were measured. A stop band, which is significantly influenced by the symmetrical characteristics of the inductor,capacitor (LC) arrays, was found in both the structures in the frequency range of 2.0,3.5 GHz. Because of their effective surface-wave suppression, MC-PBG structures can be used as high-performance antenna substrates to enhance the broadside gain of patch antenna devices. [source] Multiband MIMO antenna with independent resonance frequency adjustabilityMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2010Min-Seok Han Abstract A compact multiband multiple-input multiple-output (MIMO) antenna with a band stop matching circuit for next generation mobile applications is proposed. The proposed multiband MIMO antenna consists of two dual-band planar inverted-F antennas, which provide wideband characteristics. To improve the isolation characteristic at the long term evolution band, a band stop matching circuit was inserted at the corner of each antenna element. The proposed MIMO antenna has isolation of ,15 dB at the lower band and over 20 dB at the upper band. In addition, the resonant frequencies of the proposed MIMO antenna can be independently tuned by changing the value of the inductor or by adjusting the widths of Slit1 and Slit2. To evaluate the performance of the proposed antenna, key performance parameters such as total efficiency, envelope correlation coefficient, mean effective gain (MEG), and the MEG ratio are analyzed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1893,1901, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25334 [source] Integrated the inductors on ultra-thin Si substrate to improve the RF performance for low-noise amplifier applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2010H. L. Kao Abstract This article presents the Q-factor improvement as high as 31% of 0.8 nH spiral inductors of 90-,m-thick silicon substrate on plastic. The improvement of Q-factor is due to reducing the parasitic effect from Si substrate. The loss mechanisms of parasitic effect of inductor have been studied by thinned down the Si substrate to 90 ,m and transfer to plastic. The inductance of the inductors before and after thinned down to 90 ,m Si substrates mounted on plastic are almost identical for radio frequency circuit design. A low 0.2 dB minimum noise figure (NFmin) of low-noise amplifier circuit with 90 ,m Si substrate on plastic was obtained due to the improvement of high Q-factor inductors in the first stage for radio frequency identification applications. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1576,1579, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25249 [source] A 90 nm CMOS dual-band divide-by-2 and -4 injection-locked frequency dividerMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2010Sheng-Lyang Jang Abstract A fourth-order resonator has been implemented to design a 65 GHz injection-locked frequency divider (ILFD) implemented in a 90 nm CMOS process. The ILFD is realized with a cross-coupled nMOS LC-tank oscillator with an inductor switch for frequency band selection. The LC tank can be a second-or fourth-order resonator depending upon the on/off state of a switch across a series-tuned inductor. Measurement results show that at the supply voltage of 0.5 V, the free-running frequency is from 8.68 (16.147) to 9.928 (17.89) GHz for the low- (high-) frequency band. The divide-by-2 operational locking range is from 14.9 (30.64) to 22.2 (37.74) GHz for the low-(high)-frequency band. The divide-by-4 operational locking range is from 34.4 (64.6) to 40.35 (67) GHz for the low-(high)-frequency band. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1421,1425, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25217 [source] Very small size printed monopole with embedded chip inductor for 2.4/5.2/5.8 GHz WLAN laptop computer antennaMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2010Ting-Wei Kang Abstract A very small size planar two-strip monopole printed on a thin (0.4 mm) FR4 substrate for 2.4/5.2/5.8 GHz triple-band WLAN operation in the laptop computer is presented. With the aid of an embedded chip inductor of 5.6 nH in the longer strip of the printed monopole, a much reduced strip length for obtaining the resonant mode at about 2.4 GHz is obtained, thereby leading to a much reduced size of the antenna for the desired WLAN operation. When the antenna is mounted along the top edge of the display ground, it shows a height of 9 mm and a length of 6 mm only, which is about the smallest among the triple-band WLAN laptop computer antennas that have been reported. Details of the proposed antenna are described. Results of the fabricated prototype, including the user's hand effects on the antenna performances, are presented. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 171,177, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24843 [source] A 5-GHz low-phase noise CMOS VCO with swing boosting techniqueMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 9 2009Junhua Liu Abstract A 5-GHz CMOS VCO with improved phase noise is proposed in this article. A gate voltage boosting technique is realized with only one inductor. The proposed VCO is fabricated in 0.18 ,m CMOS process, and the measured phase noise is ,122.7 dBc/Hz@1 MHz when operates at 4.936 GHz, with a power dissipation of 5.28 mW from 1 V supply. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2061,2064, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24539 [source] A 5.79-dB NF, 30-GHz-band monolithic LNA with 10 mW power consumption in standard 0.18-,m CMOS technologyMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2009Chi-Chen Chen Abstract A 30-GHz (Ka-band) low-noise amplifier (LNA) with 10 mW power consumption (PDC) using standard 0.18-,m CMOS technology was designed and implemented. To achieve sufficient gain, this LNA was composed of three cascade common-source stages, and a series peaking inductor (Lg3) was added to the input terminal of the third stage to boost the peak gain (S21-max) from 11.7 (at 28.8 GHz) to 14.5 (at 28 GHz), i.e., 23.9% (simulation). Shunt RC feedback was adopted in the third stage for achieving good output impedance matching. At 30 GHz, this LNA achieved excellent input return loss (S11) of ,19.5 dB, output return loss (S22) of ,23.8 dB, forward gain (S21) of 11.1 dB, reverse isolation (S12) of ,49.2 dB, and noise figure of 5.79 dB. The corresponding gain/PDC was 1.11, which is better than those of the CMOS LNAs around 30 GHz reported in the literature. The measured input-referred 1-dB compression point (P1dB-in) and input third-order intermodulation point (IIP3) were ,10.9 and ,2 dBm, respectively. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 933,937, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24250 [source] Analysis of planar microwave circuits with lumped-elements by CN-FDTDMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2009Wanchun Tang Abstract A three-dimensional implementation of the lumped-element by Crank-Nicolson finite-difference time-domain (CN-FDTD) algorithm has been presented in this article. Several examples of planar microwave circuits with lumped resistor, capacitor, and/or inductor are simulated and compared with traditional finite-difference time-domain method and measurements. The accuracy of CN-FDTD implementation for lumped elements in this article has been verified. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 113,116, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23969 [source] A CMOS Colpitts voltage controlled oscillator with an enhanced transconductance methodMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2008Ching-Ian Shie Abstract This work presents a technique to enhance the performance of the conventional PMOS Colpitts VCO circuit. This technique is accomplished by adding an NMOS cross-coupled pair under the traditional differential Colpitts VCO to enhance the oscillator startup condition. The signal analysis also supports this viewpoint and presents a device-choosing method to optimize the output power and phase noise. In realization, the circuit in the CMOS 0.18-,m technology, a U-shaped inductor, and thick oxide varactors are adopted in circuit to increase the quality factor of resonant tank. The performance of VCO demonstrates a center frequency of 16.7 GHz, a FOM of ,186.2 dBc/Hz, and the phase noise of ,110.42 dBc/Hz at the 1 MHz offset from the oscillation frequency. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3160,3164, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23944 [source] A low power low noise amplifier with subthreshold operation in 130 nm CMOS technologyMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2008Ickhyun Song Abstract In this article, a 5.8 GHz ISM-band CMOS low noise amplifier (LNA) operating in a subthreshold region is presented. A conventional source degeneration inductor is eliminated for higher signal gain while providing reasonable input impedance. The LNA is fabricated using 130 nm CMOS technology and measured signal gain, noise figure, and power consumption are 13.4 dB, 5.2 dB, and 980 ,W, respectively, at target frequency. Also the LNA achieves the highest figure of merit among the recently published subthreshold LNAs. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2762,2764, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23788 [source] A 1-GHz GaN HEMT based class-E power amplifier with 80% efficiencyMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2008Yong-Sub Lee Abstract This article reports a highly efficient 1-GHz class-E power amplifier based on a GaN HEMT. The compensation elements with a series capacitor and a shunt inductor are used to compensate for the internal parasitic components of the packaged transistor. To improve output power and efficiency by suppressing harmonic powers, an output matching circuit using the transmission lines is used. The peak PAE and drain efficiency of 79.2 and 80.4% with a power gain of 18.14 dB is achieved at an output power of 41.14 dBm for a continuous wave. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2989,2992, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23803 [source] A microwave filter fabricated on the lead free piezoelectric substrate using the interdigital capacitor and bonding-wire inductorMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2008Min-Hang Weng Abstract In this letter, a lumped-element bandpass filter (BPF) fabricated on the high-dielectric constant piezoelectric substrate using the interdigital capacitor and the bonding-wire inductor is designed and implemented. The lead-free piezoelectric substrate of Bi0.5Na0.5TiO3 (BNT) ceramics prepared by a conventional solid-state reaction method and sintered at temperatures 1100°C was used as substrate. The resonant frequency could be easily controlled by varying the lengths of silver bonding wire. The design procedure using the analysis of different bond-wire lengths of silver wire is described in this work. A lumped-element BPF with a central frequency at 0.9 GHz and a fractional bandwidth of 31.53% are fabricated and measured using the network analyzer. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2594,2597, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23706 [source] Divide-by-3 LC injection-locked frequency divider with inductor over MOS topologyMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2008Sheng-Lyang Jang Abstract This letter proposes a divide-by-3 frequency divider employing inductor-over MOS topology to reduce the chip area and chip cost; the divider was fabricated using the 0.35-,m 2P4M CMOS technology. The divider consists of an nMOS cross-coupled LC oscillator and two injection MOSFETs in series with the cross-coupled NMOSFETs, and the LC resonator is composed of two inductors and varactors. At the supply voltage of 1.6 V, the divider free-running frequency is tunable from 2.17 to 2.43 GHz, and at the incident power of 0 dBm the locking range is about 1.03 GHz (14.9%), from the incident frequency 6.41 to 7.44 GHz. The core power consumption is 15.1 mW. The die area is 0.753 × 0.786 mm2. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 988,992, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23279 [source] A monolithic 1.57/5.25-GHz concurrent dual-band low-noise amplifier using InGaP/GaAs HBT technologyMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2004Shey-Shi Lu Abstract A monolithic concurrent dual-band low-noise amplifier (LNA) using InGaP/GaAs HBT technology is demonstrated for the first time. The LNA provides narrowband gain and matching simultaneously at both 1.57-GHz (GPS) and 5.25-GHz (ISM) bands. It consumes only 15-mW power and achieves transducer gains (S21) of 25.3 and 14.3 dB, input return losses (S11) of 6.8 and 11.5 dB, reverse isolation (S12) of ,30.8 and ,32.2 dB, and noise figures of 2.55 and 4.5 dB at these two bands, respectively. The performance at 5.25 GHz is comparable with the 2.45/5.25-GHz concurrent dual-band CMOS LNA with a bonding wire as the gate inductor using 0.35-m CMOS technology 1. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 58,60, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20206 [source] A comprehensive study and modeling of centre-tap differentially driven single-turn integrated inductors for 10-GHz applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2003S. F. Lim Abstract This paper presents a complete characterization of single-turn differentially driven high-quality (Q) factor inductors at 10 GHz. The separate characterization of individual physical dimension through a series of 3D electromagnetic (EM) simulations allows us to evaluate their effects on the inductor's Q and inductance L separately. The results show that single-turn inductors can generate Q greater than 20 at 10 GHz with inductance L at the sub-nano Henry range. Finally, a lumped-element equivalent circuit of the inductor was developed for predicting associated Q, L, and frequency behavior. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 182,185, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11008 [source] Characterization of monolithic spiral inductor using neural networksMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2002A. Ouchar Abstract The characterization of a monolithic spiral inductor (MSI) by using a multilayer neural network approach is presented in this Letter. The inductance, physical, and geometrical parameters are extracted in order to perform a full characterization of MSI. A three-layer neural network was used for accurate representation. The results obtained by using neural networks are compared with measured S parameters of typical MSI. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 34: 299,302, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10442 [source] Compact dual-frequency PIFA with a chip-inductor-loaded rectangular spiral stripMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2002Shih-Huang Yeh Abstract By loading a chip inductor of suitable inductance (about 12 nH or less) to a planar inverted-F antenna (PIFA) with a shorted rectangular spiral strip, the frequency ratio of the antenna's first two resonant frequencies can be controlled, which makes dual-frequency operation with a desired frequency ratio easy to achieve. In addition, with the use of a shorted rectangular spiral strip, the proposed PIFA, has compact dimensions for a fixed dual-frequency operation. Design examples of the proposed PIFA with a compact size of 7.2 × 10 × 26 mm3 to achieve dual-frequency operation at about 900 and 1800 MHz are presented. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 394,397, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10333 [source] Integrated inductors on porous siliconPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 5 2007H. Contopanagos The cover picture illustrates the effective use of a thick porous silicon layer as an integrated micro-plate for RF isolation on a silicon substrate, proposed by Harry Contopanagos and Androula Nassiopoulou in their Original Paper [1] in the current issue. What is plotted is the magnitude of the current distribution (colour coded from blue (low) to high (red) values) on the metallization and on a screen 50 µm underneath the bottom oxide layer of a 2-metal integrated CMOS-compatible inductor on bulk silicon (lower right) and on a 50 µm thick porous silicon layer (upper left) for a frequency of 2.5 GHz. Inductors were designed in a standard 0.13 µm CMOS technology. Efficient RF isolation is produced by the porous Si layer, as evidenced by the virtual elimination of surface currents relative to the case of standard CMOS, indicating virtually complete substrate shielding by a 50 µm thick porous Si layer for the relevant size scale. The quality factor of the inductor with the use of the porous Si layer is increased by 100%, reaching a maximum value of 33 for the design shown. The first author of the article is a visiting senior researcher at the Institute of Microelectronics (IMEL), National Center for Scientific Research "Demokritos" (Athens, Greece). His research focuses on electromagnetics and microwave engineering, artificial materials and photonic crystals, wireless front ends, antennas and high-frequency analog integrated circuits. [source] Production of a Polyester Degrading Extracellular Hydrolase from Thermomonospora fuscaBIOTECHNOLOGY PROGRESS, Issue 5 2002Mona K. Gouda The production of a polyester-degrading hydrolase from the thermophilic actinomycete Thermomonospora fusca was investigated with regard to its potential technical application. Only in the presence of a polyester (random aliphatic-aromatic copolyester from 1,4-butanediol, terephthalic acid, and adipic acid with around 40,50 mol % terephthalic acid in the acid component), the excretion of the extracellular enzyme could be achieved with an optimized synthetic medium using pectin and NH4Cl as nitrogen source. Compared to complex media, a significantly higher specific activity at comparable volumetric yields could be obtained, thus reducing the expenditure for purification. The activity profile in the medium is controlled by a complex process involving (1) induction of enzyme excretion, (2) enzyme adsorption on the hydrophobic polyester surface, (3) inhibition of enzyme generation by monomers produced by polyester cleavage, and (4) enzyme denaturation. Diafiltration with cellulose acetate membranes as the sole downstream processing step led to a product of high purity and with sufficient yield (60% of total activity). Scaling-up from shaking flasks to a fermentor scale of 100 L revealed no specific problems. However, the excretion of the hydrolase by the actinomycete turned out to be inhibited by the degradation products (monomers) of the aliphatic-aromatic copolyester used as inductor for the enzyme production. The crude enzyme exhibited generally similar properties (temperature and pH optimum) as the highly purified hydrolase described previously; however, the storage capability and thermal stability is improved when the crude enzyme solution is diafiltrated. [source] Entorhinal Cortex Lesion in the Mouse Induces Transsynaptic Death of Perforant Path Target NeuronsBRAIN PATHOLOGY, Issue 3 2004Adam D. Kovac Entorhinal cortex lesion (ECL) is a well described model of anterograde axonal degeneration, subsequent sprouting and reactive synaptogenesis in the hippocampus. Here, we show that such lesions induce transsynaptic degeneration of the target cells of the lesions pathway in the dentate gyrus. Peaking between 24 and 36 hours postlesion, dying neurons were labeled with DeOlmos silver-staining and antisera against activated caspase 3 (CCP32), a downstream inductor of programmed cell death. Within caspase 3-positive neurons, fragmented nuclei were co-localized using Hoechst 33342 staining. Chromatin condensation and nuclear fragmentation were also evident in semithin sections and at the ultrastructural level, where virtually all caspase 3-positive neurons showed these hallmarks of apoptosis. There is a well-described upregulation of the apoptosis-inducing CD95/L system within the CNS after trauma, yet a comparison of caspase 3-staining patterns between CD95 (lpr)- and CD95L (gld)-deficient with non-deficient mice (C57/bl6) provided no evidence for CD95L-mediated neuronal cell death in this setting. However, inhibition of NMD A receptors with MK-801 completely suppressed caspase 3 activation, pointing to glutamate neurotoxicity as the upstream inducer of the observed cell death. Thus, these data show that axonal injury in the CNS does not only damage the axotomized neurons themselves, but can also lethally affect their target cells, apparently by activating glutamate-mediated intracellular pathways of programmed cell death. [source] | ||||||||||||||||||||||||||||||||||