bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extinction ratio improvement using nonlinear four‐wave mixing in SOAs with assist beam
Authors: Dlubek Michal P. , Phillips Andrew J. , Larkins Eric C. 
Published: May 2008

AbstractThis letter presents a novel and simple scheme for all‐optical signal regeneration, based on four‐wave mixing (FWM) in semiconductor optical amplifiers (SOA). The nonlinear power transfer characteristic of the device is obtained by using the mixing product proportional to the squared power of the incoming signal. This nonlinear FWM scheme is further improved by using a strong assist beam, located close to the transparency point of the gain curve. This additional beam improves the nonlinear exponent of the transfer function; mainly by reducing gain saturation. Experimental results show that extinction ratio improvement by almost 3 dB at 4 Gb/s is obtained, accompanied by a wavelength shift of 3.3 nm. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2079–2083, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23581
A transformer‐loaded variable‐gain LNA for 24‐GHz vehicular short‐range radar
Authors: Ragonese Egidio , Scuderi Angelo , Palmisano Giuseppe 
Published: May 2008

AbstractIn this article, a 24‐GHz low‐noise amplifier for vehicular short‐range radar applications is presented. The circuit, fabricated in a 0.13‐μm SiGe:C BiCMOS process, consists of three fully differential transformer‐loaded cascode stages, including a gain‐control functionality. The amplifier exhibits a 35‐dB power gain and a noise figure of 3.4 dB, providing a reverse isolation better than −60 dB. By using a 1‐bit gain control, the LNA achieves an input 1‐dB compression point of −12 dBm. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2013–2016, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23584
Design of a multilayered dual‐band bandpass filter with transmission zeros
Authors: Weng Min‐Hang , Yang Ru‐Yuan , Chang Yu‐Chi , Wu Hung‐Wei , Shu Kevin 
Published: May 2008

AbstractIn this article, a dual‐band bandpass filter (BPF) using the multilayered structure is presented. The BPF consists of a pair of uniform impedance resonators on the top layer and a pair of step‐impedance resonators on the middle layer. By using the multilayered structure, the multitransmission zeros located near the passband edges, which is introduced by the crosscoupling effect, can be created to improve the filter selectivity. In addition, the bandwidths of the two passbands (2.4/5.2 GHz) can be tunable by adjusting the coupling gap distance between the resonators. The fabricated filter has a very compact size. Experimental results of the fabricated filter are well agreed with the simulation results. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2010–2013, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23585
Spherical vector wave functions solution to scattering of a plane wave by a spherical shell of uniaxial anisotropic left‐handed material
Authors: Geng You‐Lin , He Sailing 
Published: May 2008

AbstractBased on the spherical vector wave function in uniaxial anisotropic left‐handed‐material (LHM), the electromagnetic fields in unbounded uniaxial anisotropic left‐handed material are expanded in terms of spherical vector wave functions in uniaxial anisotropic LHM. Applying the continuous boundary conditions of electromagnetic fields in tangential direction in the spherical shell of uniaxial anisotropic left‐handed material, the expansion coefficients of electromagnetic fields in the spherical shell of uniaxial anisotropic LHM can be derived, and then the radar cross sections (RCSs) can be obtained. Some numerical results have been given and the method in this article can be applied in the areas of antenna design and system optimization, wave propagation in complex media, and electromagnetic compatibility. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2142–2146, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23586
Millimeter wave conduct speech enhancement based on auditory masking properties
Authors: Li S. , Wang J. Q. , Niu M. , Liu T. , Jing X. J. 
Published: May 2008

AbstractBesides air, the millimeter wave (MMW) provides another valuable medium to conduct speech, which may extend the traditional speech detecting method, and provides some exciting possibility for wide applications. However, the MMW conduct speech is in less intelligible and poor audibility since it is corrupted by additive combined noise. This article, therefore, proposed a simple and efficient way to take into account properties of the auditory system in the enhancement processes. The parameters of the spectral subtraction algorithm can be adaptive adjust in a perceptual sense based on a tradeoff between amount of noise reduction, the speech distortion, and the level of musical residual noise. The results from both simulation and listening evaluation suggest that the background noise can be reduced efficiently while the distortion of MMW radar speech remains acceptable, the enhanced speech also sounds more pleasant to human listeners, resulting in improved results over classical subtractive‐type algorithms. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2109–2114, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23588
A dual‐band RF switch using composite right/left‐handed transmission lines and PIN diodes
Authors: Shin Dong‐Ryul , Kim JeongPyo , Park ChangHyun , Seong Wonmo 
Published: May 2008

AbstractA dual‐band RF switch that utilizes composite right/left handed (CRLH) transmissions‐lines(TLs) and PIN diodes is proposed. The design method of RF switch is based on the phase characteristic of the CRLH‐TL, which can be adjusted arbitrary, and employed conventional type‐II; filter structure. The use of multiple PIN diodes as switching element offers prominent performance such as low insertion loss, low power consumption, and high isolation. Theoretical performance of RF switch is verified through the circuit simulations and the measurement of a fabricated prototype at 0.8 GHz and 1.6 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2074–2077, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23591
Investigation of low‐profile Fresnel zone plate antennas
Authors: Stout‐Grandy S. M. , Petosa A. , Minin I. V. , Minin O. V. , Wight J. S. 
Published: May 2008

AbstractThis article presents low‐profile configurations of the Fresnel zone plate antenna at Ka‐band. The investigation involved progressively reducing the focal distance of the antenna through simulations and observing the effect on the directivity, radiation patterns, and aperture efficiency. The number of metal zones was also varied in the simulations. It was found that focal distances below 0.75λ yielded little more directivity than the feed itself. With a single zone, the 1.25λ focal distance achieved the highest overall aperture efficiency of 24%, which was a significant improvement over the larger focal distance cases. Measurements were performed to verify the simulated results. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2039–2043, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23593
Characterization of multimode fibers for use in millimeter wave radio‐over‐fiber systems
Authors: Khawaja Bilal A. , Cryan Martin J. 
Published: May 2008

AbstractMillimeter wave radio‐over‐fiber links using both single mode and, for what is believed to be the first time, multimode fibers are demonstrated over a 0–50 GHz bandwidth using a external Mach‐ Zehnder modulator operating at 1550 nm. The multimode fiber links show the potential for use in low‐cost distributed antenna systems. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2005–2007, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23594
A 26–38 GHz millimeter‐wave band APDP sub‐harmonic mixer
Authors: Yu Shu‐Jenn , Huang Hui‐Min , Lee Ching‐Sung , Wu Chang‐Luen , Hsu Wei‐Chou 
Published: May 2008

AbstractA 26–38 GHz millimeter‐wave (MMW) band sub‐harmonic mixer has been designed using a 0.15‐μm GaAs pseudomorphic high‐electron‐mobility transistor (pHEMT) technology. The anti‐parallel diode pair (APDP) configuration as the basic unit in this sub‐harmonic mixer design to suppress the fundamental frequency signals is used. The radio‐frequency (RF) and the local oscillator (LO) signals are imported by two Lange couplers in the proposed design, with four pairs of APDPs connected in a ring structure. Superior RF/LO‐to‐IF (intermediate‐frequency) and 2LO‐to‐RF/IF isolations have been achieved. The sub‐harmonic mixer circuit has also exhibited excellent conversion loss of 13.7 dB with LO power of 13 dBm. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2135–2138, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23595
Characterization of microstrip patch antennas on metamaterial substrates loaded with complementary split‐ring resonators
Authors: Lee Yoonjae , Hao Yang 
Published: May 2008

AbstractWe present characteristics of microstrip patch antennas on metamaterial substrates loaded with complementary split‐ring resonators (CSRRs). The proposed antenna utilizes CSRRs in the ground plane altering the effective medium parameters of the substrate. To characterize the performance of the CSRR loaded microstrip antenna, the metamaterial substrate has been modeled as an effective medium with extracted constitutive parameters. Simulation results were verified by experimental results. The experimental results confirm that the CSRR loaded patch antenna achieves size reduction as well as bandwidth improvement. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2131–2135, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23596
Fast multi‐frequency extraction of 3D impedance based on boundary element method
Authors: Yu Wenjian , Yan Changhao , Wang Zeyi 
Published: May 2008

AbstractFor the boundary element method used in an impedance extractor FastImp, a scheme to handle the boundary integrals is proposed to accelerate the computation for multiple frequencies. Several techniques are combined in the scheme. The near‐field integrals are calculated with a series expansion technique and an approximate formula, whereas the precorrected FFT algorithm is employed for the far‐field integrals. Numerical experiments show that the proposed method is several times faster than FastImp for multi‐frequency extraction, while preserving high accuracy. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2191–2197, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23597
A novel three‐port tunable optical filter and crosstalk analysis
Authors: Yu Kan , Liu Wen , Huang Dexiu , Chang Jin 
Published: May 2008

AbstractAccording to the tilted incidence characteristics of thin film narrowband filter, a stack of 100‐GHz DWDM four cavities angle‐tuned narrowband thin‐film filter with low polarization dependent loss has been designed and optimized. Using the angle‐tuned filter, we developed a novel three‐port tunable optical filter. The crosstalk of the tunable filter is analyzed and calculated in detail, and the theoretical analysis result coincides with experimental result. The experiments show that the three‐port tunable filter with low polarization dependent loss has an effective tunable range of 26 nm, and it has a bright application opportunity for its flexibility and effective performance. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2163–2167, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23599
Bandpass shielding enclosure design for modern handheld communication devices with internal electric‐dipole and magnetic‐loop antennas
Authors: Chiu Cheng‐Nan , Kuo Yu‐Fan 
Published: May 2008

AbstractThis letter reveals a design approach for a bandpass shielding enclosure to be applied in modern handheld communication devices employing either an internal electric‐dipole antenna or an internal magnetic‐loop antenna. This enclosure features high transmittance at the wireless‐signal band and high shielding effectiveness outside this band, and has minimal influence on the radiation characteristics of the internal antennas used with these devices. A prototype was created and examined. The simulated and measured results demonstrate that the prototype can achieve the promised performance for either kind of internal antenna. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2223–2226, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23600
Dielectric resonator antenna element and subarray with unequal cross‐stub
Authors: Zhang Li‐Na , Zhong Shun‐Shi , Xu Sai‐qing 
Published: May 2008

AbstractA novel dielectric resonator antenna element and its 2 × 2‐element subarray are introduced, where the element is fed by a microstrip line with an unequal crossstub to expand the impedance bandwidth. Both the simulated and experimental results are presented, showing a good agreement. The proposed subarray provides a measured impedance bandwidth of 4.2% for the dielectric constant of resonator εr1 = 38 and a measured gain of 9.8–10.8 dBi across the entire operating bandwidth. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2189–2191, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23602
Optical design and performance of a novel multifunction optical device
Authors: Chen Q. H. , Wu W. G. , Wang Z. Q , Yan G. Z. , Hao Y. L. 
Published: May 2008

AbstractThis letter presents a novel MEMS‐based multifunction‐integrated optical device capable of performing as variable optical power splitter (VOPS), optical switch (OS), and variable optical attenuator (VOA). The device manipulates the light with a binary‐slope mirror driven by compound electrostatic actuator. The optical models for splitting and attenuating are investigated, respectively. Ball‐lensed fibers are assembled with the device to achieve high coupling efficiency in this work. Measurements reveal that the excess loss of the device is less than 3 dB, and the controllable attenuation range is up to 39 dB. Moreover, polarization‐dependent loss is less than 0.7 dB. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2185–2189, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23603
Design of a miniature and harmonic control patch dual‐mode bandpass filter with transmission zeros
Authors: Su Yan‐Kuin , Chen Jau‐Rung , Weng Min‐Hang , Hung Cheng‐Yuan 
Published: May 2008

AbstractA miniature and harmonic control patch dual‐mode bandpass filter (BPF) with transmission zeros for application of global positioning system (GPS) is proposed. The right crossed‐slots of the patch resonator are used to determine the main passband frequency of the BPF. In this study, by using a pair of square etched areas (SEAs) acted as perturbation elements, the dual mode filtering performance can be excited and two transmission zeros located on either side of the passband are clearly observed. It is found that two transmission zeros can improve the selectivity of the BPF as well as the stopband rejection effectively, thus avoiding the interference from other communication systems. The measured results of the fabricated BPF are in good agreement with full wave simulation. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2161–2163, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23604
A 24‐GHz active SPST MMIC switch with INGAP/GAAS HBTS
Authors: Yang Jong‐Ryul , Kim Dong‐Wook , Hong Songcheol 
Published: May 2008

AbstractA 24‐GHz single‐pole, single‐throw (SPST) switch with high isolation is designed using InGaP/GaAs HBT process. To obtain high isolation in an off state, cascode structures are utilized and an additional shunt transistor is introduced in an output, which helps to reject a leakage signal. Dummy cascode structure is used as a current steering circuit for input matching and short rise/fall time. The fabricated SPST switch shows an effective isolation of ∼52 dB at 22.8 GHz and 41 dB at 24 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2155–2158, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23606
Effect on radio frequency human exposure of mobile phone inside an enclosed metallic elevator
Authors: Tang C. K. , Chan K. H. , Fung L. C. , Leung S. W. 
Published: May 2008

AbstractThe effects of the radio frequency human exposure to mobile phone, inside both partially and fully enclosed metallic elevators, have been analyzed. It has been found that the evaluated peak Specific Absorption Rate (SAR) and the whole body absorption power are increased only by a small percentage inside the partial enclosures as compared to the free space environment; whereas inside the full enclosure, the peak SAR and the whole body absorption power are significantly increased. The analysis suggest that the reason of such a high level of RF energy absorption inside a fully enclosed metallic elevator is mainly because of the resonance effect. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2207–2210, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23612
Investigation of broadband power amplifier with high power‐combining efficiency
Authors: Song Kaijun , Fan Yong , Zhou Xiaobing 
Published: May 2008

AbstractA four‐device broadband solid‐state power amplifier, which is based on radial waveguide power‐dividing/combining circuit, has been investigated in this work. The fabricated power amplifier combining four monolithic microwave integrated circuit power amplifiers shows a 12–16.6 dB small‐signal gain over a broadband from 6 to 14 GHz. The measured maximum output power at 1 dB compression is 25.6 dBm at 10 GHz, with a high power‐combining efficiency of 96%. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2178–2181, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23614
Micro balun design and fabrication at 910 MHz and mobile RFID reader miniaturization thereby
Authors: Kim Jong‐Cheol , Jung Jin‐Woo , Roh Hyoung‐Hwan , Park Jun‐Seok 
Published: May 2008

AbstractThis article represents a microchip balun for UHF mobile RFID system at 910 MHz. This balun is designed by transforming coupled transmission lines into lumped‐element equivalent circuit, and thus monolithic elements that are fabricated by IPD technology replace it for entirely miniaturized size. The corresponding balun performs under 3 dB return loss, with nearly 176 (176.42) degree of phase difference characteristic; therefore, this meets the UHF mobile RFID reader system consideration. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2203–2206, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23617
Novel band‐notch UWB antenna design with slit ground plane
Authors: Sim Chow‐Yen‐Desmond , Chung Wen‐Tsan , Lee Ching‐Her 
Published: May 2008

AbstractA newly designed microstrip feed, octagonal‐shaped ultra‐wideband printed antenna is proposed. The UWB operation within the required 3.1–10.6 GHz band is achieved by simply embedding in the ground plane a small rectangular slit, located below the feed line of an octagonal patch. With the dimensions (length and height) of the slit carefully tuned, a notched band of around 5.1–6.4 GHz can be achieved, without applying the commonly recommended techniques of loading the radiating patch with a slot or an open‐ended slit. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2229–2233, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23621
A positive/negative refractive index coplanar transmission line in CMOS for controlled insertion phase
Authors: Symon Podilchak , Brian Frank , Al Freundorfer , Yahia Antar 
Published: May 2008

AbstractA positive/negative refractive index coplanar transmission line is presented and used for phase control in CMOS circuits. Good performance has been achieved. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2227–2230, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23622
Wideband bandpass filter using unpowered HEMT amplifiers
Authors: Kim Yong Kyu , Hwang Sung Woo 
Published: May 2008

AbstractA wideband bandpass filter using unpowered, packaged HEMT amplifiers is proposed and implemented. The key idea is to utilize very small parasitic capacitances of the unpowered HEMT as a part of the feedback loop connecting LC resonators. At the input power of −10 dBm, the 3 dB bandwidth of the fabricated bandpass filter is 93.6% of the center frequency (1.536 GHz). Furthermore, our filter does not show appreciable spurious up to 12 GHz. These internal capacitances of the HEMT extracted from the equivalent circuit modeling are shown to be in the range of 10–500 fF. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2197–2200, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23623
Erratum: Neural network estimation of RF electromagnetic pollution near TV broadcast transmitters
Authors: Çolak İlhami , Kosalay İlhan 
Published: May 2008

AbstractOriginally published in Microwave Opt Technol Lett 50: 1004‐1010, 2008. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2233, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23624
Structural determination of two new triterpenoids from Potentilla discolor Bunge by NMR techniques
Authors: Yang Jie , Chen Xiao‐Qing , Liu Xiao‐Xiao , Cao Yuan , Lai Mao‐Xiang , Wang Qiang 
Published: May 2008

AbstractTwo new pentacyclic triterpenoids, 3α, 30‐dihydroxylup‐20(29)‐en‐27‐oic acid (1) and (20S)‐3α, 29‐dihydroxylupan‐27‐oic acid (2) were isolated from the whole herbs of Potentilla discolor Bunge. The structures of these two new compounds were elucidated, and complete assignments of the 1H and 13C NMR spectroscopic data were achieved by 1D and 2D NMR experiments (HSQC, HMBC, 1H1HCOSY and ROESY). Copyright © 2008 John Wiley & Sons, Ltd.
In vivo myocardial infarct area at risk assessment in the rat using manganese enhanced magnetic resonance imaging (MEMRI) at 1.5T
Authors: Daire J.L. , Hyacinthe J.N. , Tatar I. , Montet‐Abou K. , Ivancevic M.K. , Masterson K. , Jorge‐Costa M. , Morel D.R. , Vallée J.P. 
Published: May 2008

AbstractThe aim of this study was to measure the myocardial area at risk in rat, using MRI and manganese injection during a coronary occlusion/reperfusion model at 1.5T. A sequential protocol with occlusion and MnCl2 injection immediately followed by MRI was used with the assumption that MnCl2‐induced contrast persistence is enough to accurately image the area at risk 90 min after occlusion. A total of 15 adult rats underwent a single 30‐min episode of coronary occlusion followed by reperfusion. MnCl2 was injected (25 μmol/kg) at the beginning of the occlusion for 11 rats (group 1) and 6 h after reperfusion for four animals (group 2). A deficit of signal enhancement was observed in all rats. Hypoenhancement area in group 1 was correlated to the area at risk delineated by methylene blue (r = 0.96, P < 0.0001) whereas in group 2 it was correlated to the infarct area given by triphenyltetrazolium chloride (TTC) solution (r = 0.98, P = 0.003). The area at risk size was significantly correlated with left ventricle ejection fraction (LVEF), end‐systolic volume and anterolateral wall thickening. This work demonstrates that hypoenhanced zone obtained after manganese injection during occlusion represents the area at risk and not only the infarct zone. Magn Reson Med 59:1422–1430, 2008. © 2008 Wiley‐Liss, Inc.