bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biological agents for ulcerative colitis: Hypes and hopes
Authors: Danese Silvio , Angelucci Erika , Malesci Alberto , Caprilli Renzo 
Published: April 2007

AbstractUlcerative colitis (UC) is an idiopathic chronic inflammatory disease of the colonic mucosa. Over the last decade, the increasing knowledge on the pathogenic mechanisms underlying intestinal inflammation has led to the development of a number of biological agents, mainly addressed to molecules and/or pathways demonstrated to have a pathogenic role in UC. In UC, clinical course and therapeutic decisions mainly depend on disease activity and extent. While therapeutic approach to mild‐to‐moderate UC by using aminosalicylates and corticosteroids has been well established, treatment of severe UC is far from being satisfactory. A severe attack of UC remains a challenge to be managed jointly by gastroenterology, surgery, and intensive care units. However, the recent introduction of biological therapies has led to promising changes in the management of UC patients. Aim of this paper is to review the recent advances and future perspectives for the use of biological agents in UC. © 2007 Wiley Periodicals, Inc. Med Res Rev, 28, No. 2, 201–218, 2008
Wide locking range divide‐by‐4 injection locked frequency dividers
Authors: Lee Shao‐hua , Jang Sheng‐Lyang , Lee Chien‐Feng , Juang Miin‐Horng 
Published: April 2007

AbstractThis article proposes techniques for improving locking range of divide‐by‐4 injection locked frequency divider (D4ILFD). Two D4ILFDs were designed and implemented. One D4ILFD is made of tapped resonator; the other ILFD is made of switched resonator. Both circuits use a complementary CMOS LC‐tank oscillator and are based on the direct injection topology. The wideband function of switched resonator D4ILFD is obtained by tuning the switch across the tank inductors and the varactors. At the supply voltage of 1.8 V and at the incident power of 0 dBm, the locking range of switched resonator D4ILFD is from 7.11 to 9.4 GHz. At the supply voltage of 1.2 V and at the incident power of 0 dBm, the locking range of the tapped inductor D4ILDS is from 7.39 to 9.44 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1533–1536, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22481
A simple spice model for traveling wave semiconductor laser amplifier
Authors: Das Barman Abhirup , Sengupta Ipsita , Basu P. K. 
Published: April 2007

AbstractAn equivalent lumped element electric circuit model for traveling wave semiconductor laser amplifier has been developed using the rate equation for carriers. SPICE simulation of the circuits gives results in close agreement with the experimental data and values from sophisticated analyses. The modulation bandwidth and transient response were examined by including parasitic elements in the intrinsic model. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1558–1561, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22483
Magnitude of the voltage reflection coefficient of terminated reciprocal uniform lossy transmission lines
Authors: Torrungrueng D. , Wongwattanarat A. , Krairiksh M. 
Published: April 2007

AbstractIn this paper, lossy transmission lines with arbitrary loss are analyzed in detail. Interestingly, analytical results show that the magnitude of the voltage reflection coefficient could be greater than unity for some passive load terminations. However, it can be shown rigorously that the input power is always greater than or equal to the power at the load; i.e., it still satisfied the law of power conservation even when the magnitude of the voltage reflection coefficient is greater than unity. In addition, the Smith chart is also employed to graphically illustrate that the magnitude of the voltage reflection coefficient at some points along lossy transmission lines could be greater than unity for proper load terminations. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1516–1519, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22490
Time response of ASE‐XGM wavelength conversion in SOAs using ultrashort pulses
Authors: de Oliveira Ribeiro Rafael , Pontes Maria José , Lima Rodolfo A. A. , Giraldi Maria Thereza M. R. , Carvalho Maria Cristina R. 
Published: April 2007

AbstractThe time response of a semiconductor optical amplifier wavelength converter based on the ASE‐XGM technique was experimentally obtained using ultra‐short pump optical pulses. The results were compared with the pump & probe technique and show similar time responses. The conversion efficiency of the ASE‐XGM technique was measured for different pump power levels and presented promising results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1541–1544, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22492
Study of optically controlled high temperature superconducting microwave variable attenuator
Authors: Liu Lin , Ye Yutang , Wu Yunfeng , Chen Zhenlong , Wang Yulin 
Published: April 2007

AbstractA novel optically controlled HTS (high temperature superconducting) microwave variable attenuator was proposed and a sample was tested, which can be used solely, or be integrated into the HTS system. Utilizing the very low microwave superficial resistance and superexcellent optically response character of YBCO film, the insertion loss of sample is lower than 0.2 dB and variable attenuation precision is 0.01 dB at least. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1539–1541, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22494
Impact of the variable output resistance on the transient response of LC transmission line CMOS buffers and its model
Authors: Cappuccino Gregorio , Crupi Felice , Pugliese Andrea 
Published: April 2007

AbstractThe work focuses on the impact of the finite and variable MOSFET output resistance on the transient response LC transmission line drivers. Experimental results highlight the severe error occurring in conventional timing analysis when actual finite resistance of the device is neglected. A novel analytical model is presented to capture the variable resistance of the driver. The model allows closed‐form expressions for the output waveform to be carried out, and it agrees well with HSPICE simulations. The proposed model is suitable to figure fundamental timing parameters of CMOS gates driving lossless transmission lines, such as the propagation delay, transition time, as well as power estimation. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1504–1509, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22496
Multiband antenna system with polarization conversion for WLAN applications
Authors: He Wei , Jin Ronghong , Geng Junping , Gao Bo 
Published: April 2007

AbstractIn this article, an antenna system consisting of two inverted‐F antenna arrays printed on one substrate for polarization conversion is proposed. The two antenna arrays are designed for triple‐band operation at about 2.4, 5.25, and 5.8 GHz for antenna selection diversity in IEEE 802.11a/b/g WLAN applications. Simulation and measurement results for main parameters, such as return loss, impedance bandwidth, radiation pattern, and gains are also discussed herein. The study shows that modeling of such antenna system, with simplicity in designing, can well meet the requirements of IEEE 802.11a/b/g WLAN applications and support antenna diversity by selection of the antenna (one out of two) with the highest receiving signal strength for polarization conversion. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1772–1777, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22501
Novel dual‐mode square‐loop resonators using Hilbert perturbation for simultaneous size reduction and mode splitting
Authors: Liu Ji‐Chyun , Lu Po‐Chiang , Chang Jun‐Mao , Chien Chi‐Hsu , Kuei Ching‐Pin 
Published: April 2007

AbstractThe novel dual‐mode square‐loop resonator (DMSLR) with Hilbert perturbation is introduced to design bandpass filter in this paper. To obtain low insertion loss (0.55 dB), high out‐of‐band rejection level (−28.8 dB), and wider splitting band (BW 26.14%) filters, iterative Hilbert perturbation and space‐filling technique usage are proposed here. Significant size reduction of over 19% is obtained at 0.948 GHz. Results including surface current distributions and frequency responses are presented and discussed. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1735–1739, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22503
Improving the radiation characteristics of a base station antenna array using a particle swarm optimizer
Authors: Zaharis Z. D. , Kampitaki D. G. , Lazaridis P. I. , Papastergiou A. I. , Hatzigaidas A. T. , Gallion P. B. 
Published: April 2007

AbstractA particle swarm optimization based technique is applied on linear antenna arrays used by broadcasting base stations. Both the geometry and the excitation of the antenna array are optimized by a suitable algorithm under the constraints of the maximum possible gain at the desired direction and the desired value of side lobe level. The matching condition of the elements of the antenna array is also required by the algorithm. The technique has been applied to antenna arrays composed of collinear wire dipoles and seems to be very promising for improving radiation patterns of base station antenna arrays in many practical applications. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1690–1698, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22505
Design of high‐performance three‐strip 3‐DB directional coupler in multilayer technology with compensated parasitic reactances
Authors: Gruszczynski Slawomir , Wincza Krzysztof , Sachse Krzysztof 
Published: April 2007

AbstractRecently developed technique of discontinuity effect compensation in coupled stripline directional couplers, regarding the connection of coupled and terminating signal lines, has been for the first time applied to the design of multilayer three‐strip 3‐dB directional couplers. Results of simulations and measurements are presented to confirm usefulness of the technique. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1656–1659, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22507
Holey fiber analysis employing FDM and FDTD methods on the transverse plane
Authors: Kim Jeong I. 
Published: April 2007

AbstractConsidering applicability to the analysis of holey fibers with random air‐hole arrangement on a transverse plane, finite‐difference time‐domain, and finite difference method (FDM) techniques are proposed to evaluate the transmission properties such as normalized propagation constant, chromatic dispersion, and effective area. Results are in remarkable agreement with the published data. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1592–1594, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22511
Tolerance analysis of a PCS ceramic monoblock filter
Authors: Tsitsos S. , Kyriazidis P. , Gibson A. A. P. 
Published: April 2007

AbstractUsing an efficient equivalent circuit approach, the performance of a PCS ceramic monoblock filter under dimensional and material variations is thoroughly investigated. Graphs are used to understand how perturbations in the filter geometry affect the equivalent circuit and filter performance. It is noted that the critical tolerances are associated with the dielectric constant and resonator length. It follows that this method provides an efficient route to adjusting the filter design for a new specification without having recourse to costly electromagnetic solvers. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1759–1764, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22514
Design and characteristics of a small U‐slotted planar antenna for IR‐UWB
Authors: Vuong Tan‐Phu , Ghiotto Anthony , Duroc Yvan , Tedjini Smail 
Published: April 2007

AbstractThis article introduces the design of a small (30 mm × 35 mm × 1.6 mm) band‐rejected U‐slotted planar antenna on FR4 substrate having a relative permittivity of εr= 4.4 for Impulse Radio Ultra Wide Band (IR‐UWB) systems. The antenna is fed by a microstrip line and rejects the frequency band from 5.15 GHz to 5.825 GHz used by IEEE 802.11a and HIPERLAN/2. This antenna shows good characteristics for IR‐UWB. The effects of variation on steps and U‐Slot are discussed. The antenna is characterized both in the time and frequency domains by use of simulation and measurement.© 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1727–1731, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22515
An improved method of approaching impedance computation of probe fed ring resonator
Authors: Mahajan Madhurika , Chakravarty Tapas , Khah Sunil Kumar 
Published: April 2007

AbstractIn this article a new method of computation of input impedance of a probe‐fed ring resonator is presented. The method utilizes both cavity model and circuit theory to accurately predict the impedance of a high Q‐dominant mode resonance. Apart from accurate, this method can be generalized to predict impedance of first few modes of a probe‐fed ring resonator to reasonable accuracy. The computed result is compared with previously published data for TM12mode and discrepancies observed are listed. The method is also used to compute impedance for first few modes. For dominant mode, the numerical results are compared with IE3D results, which is a commercially available software based on method of moments. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1681–1684, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22518
Controllable metamaterial electrmagnetic structure research on applying to stealth technology
Authors: Xu Zhanxian , Lin Weigan , Kong Lidu 
Published: April 2007

AbstractIn this article, we present a new kind of a controllable metamaterial electromagnetic structure that it may be applied into stealth design and stealth technology in the future, in which the transmission coefficient of electromagnetic wave and single radar cross section (RCS) of structure are both electrically controlled, simulated, and characterized between 7 and 12 GHz. This structure is constructed with split ring resonators (SRRs) and metallic wire arrays including pin diodes, pin diodes are periodically inserted at these discontinuous each 10 mm to control the electrical continuity of the wires, and they can be either in an on state or in an off state depending on the voltage. the simulation and test prove that this structure could absorb electromagnetic incident wave, and have reduced RCS markedly with the largest scope of ‐6 dBm around frequency 9.0 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1616–1619, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22521
Experimental evaluation of indoor MIMO channel capacity for compact arrays of planar inverted‐F antennas
Authors: Carrasco Héctor , Feick Rodolfo , Hristov Hristo D. 
Published: April 2007

AbstractEmpirical results on indoor multiple input multiple output (MIMO) channel capacity obtained through the use of planar inverted‐F antennas (PIFA) are presented. An extensive statistical study done at 2.45 GHz reveals how antenna proximity and array configuration affects MIMO capacity. It is concluded that certain linear or square PIFA based arrays allow very compact multi‐antenna arrangements without significant capacity loss. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1754–1756, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22526
A very‐low‐profile broadband planar antenna for DCS‐1800 and IMT‐2000 applications
Authors: Li R. L. , Pan B. , Laskar J. , Tentzeris M. M. 
Published: April 2007

AbstractA very‐low‐profile (VLP) broadband planar antenna is developed for DCS‐1800 and IMT‐2000 handsets. The VLP planar antenna consists of an S‐strip and a T‐strip, which are separately printed on the two sides of a thin substrate. The antenna height is only 4.8 mm which is much lower than previously published antenna configurations. The VLP planar antenna can achieve a bandwidth of ∼30% for return loss < ‐ 10 dB. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1679–1681, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22529
Using high permittivity ceramic substrates to fabricate a miniaturized bandpass filter with capacitive load
Authors: Huang Cheng‐Liang , Wang Jun‐Jie , Li Po‐Hsin 
Published: April 2007

AbstractUsing high permittivity ceramic substrates and capacitive coupling to miniaturize the sizes of Butterworth bandpass filters are investigated. The selectivity and stopband rejection of the designed filters can be improved significantly by utilizing a skew‐symmetric (zero degree) feed structure. These factors result in reducing the size of the filter. The responses of the Butterworth filters using Al2O3(εr= 10,Q × f= 20,000 GHz) and 0.85(Mg0.95Zn0.05)TiO3− 0.15Ca0.6La0.8/3TiO3(εr= 26,Q × f= 86,000 GHz) ceramic substrates are designed at a center frequency of 2.4 GHz. The compact size, low‐loss, sharp response, and performance of the filter are presented in this article. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1609–1613, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22533
Reshaping of picosecond optical pulses with a simple interferometer
Authors: Xianwei Zhou , Jianping Wang 
Published: April 2007

AbstractIn optical fiber communication systems, reshaping is crucial for long‐haul transmission and networks due to the accumulated noise and dispersion, which will gradually degrade the signals. In this article, a SOA (Semiconductor Optical Amplifier)‐based interferometer is proposed to realize all‐optical signal reshaping. Such scheme is known as advantageous for operation at high speed, which is analyst in theory. The distorted picosecond optical pulses train with repetition rate of 10 GHz is reshaped successfully in experiments employing this simple interferometer. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1606–1608, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22534
High‐coupling and ultra‐low‐loss interlaced stacked transformers for 60 100‐GHz CMOS RFIC applications
Authors: Lin Yo‐Sheng , Chen Chi‐Chen , Chen Chang‐Zhi , Yeh Po‐Feng 
Published: April 2007

AbstractIn this article, we demonstrate that high‐coupling and ultra‐low‐loss transformers for 60–100‐GHz CMOS RFIC applications can be achieved by using single‐turn two‐layer interlaced stacked (STIS) structure implemented in a standard CMOS technology. State‐of‐the‐art GAmaxof 0.711, 0.922, and ∼1 (i.e., NFminof 1.48, 0.35, and ∼0 dB) were achieved at 60, 80, and 100 GHz, respectively, for a STIS transformer with an inner dimension of 50 × 50 μm2and a metal width of 5 μm, mainly due to the high magnetic‐coupling factor and the high resistive‐coupling factor. In addition, a 94.1% (from 5.61 to 10.89) and a 196.8% (from 8.36 to 24.81) increase in Q‐factor, a 14.2% (from 0.711 to 0.812), and an 8.5% (from 0.922 to ∼1) increase in GAmax, and a 0.58 dB (from 1.48 to 0.90 dB) and a 0.35 dB (from 0.35 to ∼0 dB) decrease in NFminwere achieved at 60 and 80 GHz, respectively, for the transformer after the post‐process of proton implantation. The present analysis is helpful for RF engineers to design ultra‐low‐voltage high‐performance 60–100‐GHz transformer‐feedback CMOS (or BiCMOS) LNAs and VCOs, and other RF‐ICs which include transformers. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1750–1753, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22537
A Ku‐band three‐stage mmic low‐noise amplifier with superiorly low thermal‐sensitivity coefficients
Authors: Yu Shu‐Jenn , Hsu Wei‐Chou , Lee Ching‐Sung , Chang Chian‐Sern , Wu Chang‐Luen , Chang Ching‐Hsueh 
Published: April 2007

AbstractA three‐stage monolithic microwave integrated‐circuit (MMIC) low‐noise amplifier (LNA) design with superiorly low thermal‐sensitivity coefficients in both the small‐signal gain and noise figure characteristics is reported. The amplifier is constituted by using the AlGaAs/GaAs pseudomorphic high electron mobility transistors (pHEMTs). It is suitable for the commercial applications at Ku‐band frequencies. Besides, a compact self‐biased structure with a single‐bias supply was employed to simplify the circuit and improve thermal stability. A noise figure of 2.3 dB with an associated gain of 22 dB is achieved at 16 GHz, and the output power, P1dB, is 17 dBm. The proposed LNA has demonstrated excellent thermal stability. The thermal‐sensitivity coefficients for the small‐signal gain and the noise figure are superiorly as low as 0.023 and 0.003 dB/°C, respectively, with respect to the temperature variation from −15 to 85°C. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1637–1641, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22543
An optical link for microwave clock distribution using optical carrier suppression and DC drift compensation
Authors: Onillon Bertrand , Danès Patrick , Bénazet Benoît , Llopis Olivier 
Published: April 2007

AbstractBias electrode DC drift of LiNbO3optical modulators becomes a critical problem when these devices operate over a long time period. This article presents a novel system of DC drift compensation for optical microwave transmissions using optical carrier suppression technique. In our case, such a system is dedicated to the optical distribution of high spectral purity microwave signals in future satellite payloads. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1634–1637, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22544
Compact semilumped elliptic‐function low‐pass filter using microstrip meander line
Authors: Lee Ju Gab , Lee Wu Seong , Ryu Jae Jong , Moon Yeon Kwan , Jang Joong Ho , Kim Ha Chul , Choi Hyun Chul 
Published: April 2007

AbstractFor the size reduction and sharp attenuation of the low‐pass filter in lower RF frequency range, a semilumped elliptic‐function low‐pass filter was proposed using microstrip meander line, chip capacitor, and radial stubs. To estimate more accurate inductance of microstrip meander line, it was modeled in an inhomogeneous dielectric environment, and then the calculated inductance was compared with the conventional case. To provide an additional attenuation pole in stop‐band, radial stubs were added to the proposed structure. The 3‐order low‐pass filter has a cutoff frequency of 1GHz and dimension of 14.6 × 16.3 mm2 on the substrate with a relative dielectric constant of 3.38. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1777–1779, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22545