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Wide Band (wide + band)
Selected AbstractsBasic study of pole change generator for micro windmill generation systemELECTRICAL ENGINEERING IN JAPAN, Issue 1 2010Kazuto Yukita Abstract This paper proposes a pole change generator for a windmill. Since micro windmill systems generate power from natural energy, power generation characteristics across a wide band are necessary. However, the conventional generator, in which the open voltage is simply proportional to the rotational velocity, encounters difficulty in generating power across a wide range of rotational velocities from low to high, because of the power generation characteristics. To develop a generator with a wide power band suitable for a micro windmill, this paper proposes a technique for switching the status of the generator coil connection. To demonstrate the effectiveness of pole changing, we use a pole-changing generator with 16 coils as an example. The coils can be connected using four patterns: 16-pole series, 8-pole 2-parallel, 4-pole 4-parallel, and 2-pole 8-parallel. Theoretical and experimental studies from this point of view demonstrate that this technique is effective. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(1): 28,36, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20873 [source] Analysis and modeling of microstrip-to-coplanar flip chip package interconnectsINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 4 2001Hussein H. M. Ghouz Abstract In this paper, the discontinuity of a flip chip transition between a microstrip line and a coplanar waveguide is investigated and modeled using the finite-difference time-domain method (FDTD) to predict the overall S -parameters of the package. Effects of the bump and via interconnects on the package performance are investigated and discussed. This includes the effects of different staggered transitions and ground connects on the package performance. A reduction of about 10 dB in the bump and via reflections can be achieved by staggering the signal (bump) and the ground connects (bump/via). A staggering distance of about twice the slot width gave minimum reflection over a wide band of frequencies. Moreover, the larger the relative distance between the ground and the center connects the less the reflection due to the discontinuity. Finally, the computed S -parameters of the flip chip package using the FDTD solution are used to develop an equivalent circuit model for the transition discontinuity over a wide frequency band. The equivalent circuit model of the microstrip to coplanar waveguide discontinuity includes more elements and is more complex than other types of transitions. A TEE or PI circuit model has been used to approximate the general circuit model of the discontinuity. Good agreement has been obtained between the S -parameters of the FDTD model and the equivalent circuit models over a wide frequency band. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 202,211, 2001. [source] Compact microstrip power divider with both sides capacitor loadingMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2010Jun He Abstract A compact microstrip Wilkinson power divider with both sides capacitor loading is presented in this letter. The new divider, not only effectively reduces the occupied area to 33.6% of the conventional one at 1.0 GHz, but also has good harmonic suppression performance over a wide band. Furthermore, the new structure has only two variable parameters and can be easily designed. The design is validated both by simulation and measurement. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1663,1664, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25286 [source] Half-cut disc UWB antenna with tapered CPW structure for USB applicationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2010Wen-Jian Liu Abstract A novel half disc for ultra wide band (UWB) application is proposed with the beveled ground and tapered coplanar waveguide-fed structure. Its impedance bandwidth ranges from 2.42 to 13.62 GHz, which covers the entire UWB band. Its dimension is as small as 11 mm × 29.3 mm. As a result, it can be easily integrated into the wireless USB equipments. The simulated and measured results have a relative good agreement. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1380,1384, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25193 [source] Compact rat-race ring coupler with capacitor loadingMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2010Wei Shao Abstract A simple compact microstrip rat-race ring coupler with capacitor loading is presented in this letter. The new coupler not only effectively reduces the occupied area to 15% of the conventional one at 1.0 GHz, but also has high harmonic suppression performance over a wide band. Furthermore, the new structure has only two variable parameters and can be easily designed. The design is validated both by simulation and measurement. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 7,9, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24823 [source] Metamaterial transmission lines with tunable phase and characteristic impedance based on complementary split ring resonatorsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2009Adolfo Vélez Abstract In this article, resonant-type tunable metamaterial transmission lines with independent control over the electrical parameters of the line, that is, the electrical length and characteristic impedance, are presented for the first time. Tuning is achieved by loading a host microstrip line with varactor-loaded complementary split ring resonators (VLCSRRs) and varactor diodes. By locating the varactor diodes in series configuration with the line, outside the region occupied by the VLCSRRs, it is possible to control the characteristic impedance and the electrical length (phase shift), over a wide band. As an illustrative example, a tunable 35 ,/90° line functional between 0.4 and 0.8 GHz (which represents more than 65% tuning range), is presented and applied to the design of a transmission line power divider. The device is small and it exhibits reasonable performance. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1966,1970, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24480 [source] A compact dual-band modified T-shaped CPW-fed monopole antennaMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2009R. Sujith Abstract A compact, dual band coplanar waveguide fed modified T-shaped uniplanar antenna is presented. The antenna has resonances at 1.77 and 5.54 GHz with a wide band from 1.47,1.97 GHz and from 5.13,6.48 GHz with an impedance bandwidth of 34% and 26%, respectively. Also the antenna has an average gain of 3 dBi in lower band and 3.5 dBi in higher band with an average efficiency of 90%. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 937,939, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24249 [source] Compact dual-band multilayer antenna element for nonlinear junction detector applicationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2009Krzysztof Wincza Abstract A compact dual-band antenna element for application in a nonlinear junction detector is proposed. To achieve broadband characteristics in two separate frequency ranges a stratified structure is proposed in which two driven and two parasitic patches are properly placed. For transmitting, a circularly polarized antenna is used in which stacked square ring resonators are applied to achieve simultaneously broadband operation and compact size. For receiving, a dual-polarized antenna is proposed in which a square patch is loaded by a square ring resonator to provide wide band and to allow for integration with the transmitting antenna. Theoretical calculations confirmed by measurement results are presented. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 696,699, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24136 [source] The posterior longitudinal ligament and peridural (epidural) membraneCLINICAL ANATOMY, Issue 6 2006Peter R. Loughenbury Abstract The posterior longitudinal ligament (PLL) is described as having deep and superficial layers, though recent studies have suggested that there may be three layers. Additional membranous structures have been reported, although there is no consensus as to their presence or morphology. The vertebral canal and dural sac were opened and the spinal nerve roots and spinal cord removed. The anterior dural ligaments were sectioned at their attachment to the PLL and the dura mater freed from the posterior surface of the vertebral bodies. The borders of the PLL were identified and the superficial and deep layers separated. The PLL is a wide band in the cervical region becoming more denticulate inferiorly, the widest parts being attached to the intervertebral discs (IVD) and adjacent vertebral body where the superficial and deep layers could not be separated. A continuous well developed peridural membrane attaching to the pedicles was present anterior to the deep PLL as well as a separate, thin, incomplete layer in 6 of 18 cadavers, covering the posterior surface of the superficial PLL. Clin. Anat. 19:487,492, 2006. © 2005 Wiley-Liss, Inc. [source] | ||||||||||