bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel design on broadband circularly polarized microstrip antenna
Authors: Li Zhu , Guang‐Ming Wang , Xiang‐Jun Gao 
Published: February 2008

AbstractA square array of air columns is embedded in a dielectric substrate to form the photonic‐bandgap (PBG) structure and the band‐gap of such a PBG structure is analyzed at first. Then a broadband circularly polarized antenna based on the PBG structure is introduced. Through selecting appropriate lattice period and air column radius, the surface wave can be suppressed effectively and the circularly polarized characteristic can be improved when the resonant frequency (f = 12.5 GHz) of the antenna fell in the band‐gap of the PBG structure. After calculating and testing, the 20.6% (VSWR [lt] 2) bandwidth and 27.4% 3‐dB axial ratio bandwidth are achieved, respectively. Such circularly polarized antenna can be used extensively in communications field. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 954–957, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23257
Waveguide power dividers using multiple posts
Authors: Akbarzadeh Ali Reza , Shen Zhongxiang 
Published: February 2008

AbstractA new rectangular waveguide power divider using multiple posts is described in this paper. The waveguide power divider is easy to fabricate and is particularly suitable for substrate‐integrated waveguide (SIW) circuits. Two designed examples are presented: one is a rectangular waveguide power divider using nine posts along theE‐plane and the other is a SIW waveguide power divider in which three inductive via holes are used. The measured results for the two designed power dividers are presented and compared with the simulated ones by Ansoft's high‐frequency structure simulator, and good agreement is observed. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 981–984, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23259
Compact wideband DGS lowpass filter with modified microstripline
Authors: Or Y. C. , Leung K. W. 
Published: February 2008

AbstractA compact microwave lowpass filter with three transmission zeros is designed using the defected ground structure (DGS). The microstripline section above the DGS region is modified to obtain remarkable slow‐wave and bandgap effects. An equivalent lumped L–C circuit model is presented. Reasonable agreement among the simulated, modeled, and measured results is obtained. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 974–977, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23263
A symmetric log‐periodic balun for ultra‐wideband application
Authors: Chen Chu‐Yu , Ye Shu‐Hao 
Published: February 2008

AbstractCompared with the conventional log‐periodic balun, the design of a symmetric log‐periodic balun can provide better performance over the entire designed band. A novel ultra‐wideband (UWB) balun with 3–6 GHz passband is demonstrated for UWB applications. The problems of fabrication and measurement of the conventional log‐periodic balun operated at higher frequency problems can be further improved. The magnitude and phase difference between two output ports are kept balancing at higher band edge portion. The measured amplitude imbalance is about ±1.1 dB with a corresponding phase difference about ±4°. The bandwidth of the balun is around 70%. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 947–948, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23264
A high‐power Cartesian feedback transmitter including a compact inverted Doherty amplifier
Authors: Cho Hanjin , Kim Min‐su , Jeong Jong‐hyuk , Van Juho , Jung Sung‐chan , Park Hyunchul , Lim Kyung‐hoon , Kwon Sung‐wook , Kim Jae Young , Song Sung Chan , Park Cheon‐Seok , Yang Youngoo 
Published: February 2008

AbstractA high‐power Cartesian feedback transmitter including a compact inverted Doherty amplifier is presented. The system efficiency was further improved using a bias line adjustment method for the compact inverted Doherty amplifier. After the bias line adjustment from a λ/4 line for the Doherty amplifier, a power‐added efficiency (PAE) of 6.9% points was improved from 41.3 to 48.2% at an output power level of 45 dBm. The whole Cartesian feedback transmitter system exhibited an efficiency of 40% and an adjacent channel leakage ratio of‐51 dBc at an output power of 45 dBm for 859 MHz band π/4‐DQPSK applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 944–946, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23265
A compact meandering bandpass filter with dual passband performance for 2.4/5.7 GHz WLANs
Authors: Kuan Hon 
Published: February 2008

AbstractIn this letter, a compact dual‐band bandpass filter (BPF) using the meandering stepped impedance resonators (MSIRs) for the wireless local area networks (WLANs) is proposed. The dual‐band performance of the BPF is adjusted by the physical length (α) and impedance ratio (K) of the MSIRs. The proposed BPF is designed and fabricated, showing good dual‐passband responses at 2.4/5.7 GHz and a high isolation between the two passbands. The overall circuit size of the BPF is much smaller than the previous work. Good agreement with response of electromagnetic (EM) simulation and measurement is obtained. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 969–971, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23267
Fourth‐order accurate sub‐sampling for finite‐difference analysis of surface plasmon metallic waveguides
Authors: Hu Bobo , Sewell Phillip , Wykes James G. , Vukovic Ana , Benson Trevor M. 
Published: February 2008

AbstractRecently, particular attention has been given to metallic waveguides supporting surface plasmons as promising components for integrated optical devices. However, the use of conventional numerical optimization tools for their design is hindered by the intensive computational effort associated with meshing down to the resolution of the thin metallic layer. In this study, the previous three‐point second order accurate finite‐difference formula suitable for correctly placing thin dielectric layers within coarse grids is extended to fourth order accuracy by using the generalized Douglas scheme, including the case when thin metallic layers supporting surface plasmons lie wholly between sample points. The improved formulation, combined with an imaginary distance procedure, is used to analyze the eigenmodes of both 2D and 3D thin metal films located upon dielectric substrates. Accurate calculation with coarser meshes than those required by the other standard differencing schemes is demonstrated, thus providing both a significant saving in computational resource and an extra degree of freedom in meshing such structures. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 995–1000, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23271
Novel substrate integrated folded waveguide filter
Authors: Alotaibi Sultan K. , Hong Jia‐Sheng 
Published: February 2008

AbstractIn this study, a novel substrate integrated folded‐waveguide resonator filter is presented and an aperture coupling between adjacent resonators is introduced, which is characterized using full‐wave EM simulations and verified experimentally. A demonstrator of two‐pole substrate integrated folded‐waveguide resonator filter of this type has been designed, fabricated, and tested. As an example, a two‐pole BPF centered at 4.675 GHz with a fractional bandwidth of 7.4% is designed, fabricated, and measured. Simulations and experimental results are presented to validate the design and to show the advantages of this type of filter. The simulated and measured results show an excellent agreement. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1111–1114, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23272
Design of compact stop‐band extended microstrip low‐pass filters by employing mutual‐coupled square‐shaped defected ground structures
Authors: Boutejdar A. , Makkey M. , Elsherbini A. , Omar A. 
Published: February 2008

AbstractA new technique to reduce the size, improve the rejection in the stop‐band of a low‐pass filter using modified defected ground structure (DGS) is proposed. An equivalent circuit model is used to study the DGS characteristics. The parameters are extracted by using a simple circuit analysis method. Several comparisons between the EM‐simulations and the circuit simulations of the new structure are demonstrated to show the validity of the proposed equivalent circuit model. We demonstrated that the filter can provide a sharp transition domain and a wide rejection in stop‐band. To further verify the new technique, a filter employing the new deformed DGS is fabricated and measured. The agreement between the simulation and the measured results confirms the effectiveness of the proposed concept. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1107–1111, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23273
Low‐loss and broadband BGA package transition for LTCC‐SiP applications
Authors: Kangasvieri T. , Halme J. , Vähäkangas J. , Lahti M. 
Published: February 2008

AbstractA high‐performance broadband ball‐grid‐array (BGA) package transition was designed and implemented from DC up to the Ka‐band frequencies. The vertical BGA‐via transition path starts from an organic motherboard (PCB) and ends at the top surface of a low‐temperature cofired ceramic module package. To assess solder joint reliability, large plastic‐core solder balls with a diameter of 800 μm were employed. The measured insertion loss of the entire vertical transition path, including feedlines, was better than 0.5 dB (1 dB) up to 25 GHz (29 GHz). Moreover, an equivalent circuit model for the complete transition path was developed. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1036–1040, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23276
Implementation of rigorous EM simulations for design and production of narrow band waveguide diplexer
Authors: Markovic Dusan , Jokanovic Branka , Kiriazi John , Lubecke Victor 
Published: February 2008

AbstractIn this article the advanced modeling and simulation of narrow band waveguide diplexer for radio‐relay links at 13 GHz is presented. Three different electromagnetic simulation packages were used for design of diplexer with 0.76% of fractional bandwidth and 2% of channel spacing. Simulation tools are compared concerning their accuracy in the prediction of central frequency, bandwidth, insertion and return losses and out of band attenuation. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1032–1036, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23277
Multiband surface‐mount chip antenna integrated with the speaker in the mobile phone
Authors: Chang Chih‐Hua , Wong Kin‐Lu , Row Jeen‐Sheen 
Published: February 2008

AbstractA surface‐mount chip antenna integrated with the speaker in the mobile phone for GSM/DCS/PCS/UMTS multiband operation is presented. The antenna is to be mounted on the top no‐ground portion of the system circuit board of the mobile phone as an internal multiband antenna, and the speaker in the mobile phone can be inset into the chip base of the antenna to achieve a compact integration of the antenna and the speaker. Moreover, the chip antenna occupies a small volume of 35.5 × 10 × 7 mm3 (about 2.5 cm3) only. Details of the proposed chip antenna are presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1126–1132, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23287
Dual‐band filter using equal‐length split‐ring resonators and zero‐degree feed structure
Authors: Fan J. W. , Liang C. H. , Wu B. 
Published: February 2008

AbstractA compact dual‐band microstrip filter with equal‐length split‐ring resonators and 0°‐feed structure is proposed in this article. The frequency splitting effect of the equal‐length SRRs is described in detail. A 0°‐feed structure is introduced and applied to realize additional transmission zeros at finite frequencies. The measurement of the filter is in good agreement with the simulation. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1098–1101, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23288
A broadband dual‐fed notched suspended plate antenna
Authors: Kian Toh Wee , Ning Chen Zhi , Ming Qing Xian 
Published: February 2008

AbstractA single‐layer dual‐fed suspended plate antenna (SPA) with a notched radiator and broad lateral width is presented for high gain and broad coverage applications. Both the impedance and gain bandwidths of the proposed antenna are increased by extending the radiation aperture, while the occurrence of high‐order modes is suppressed by using a dual‐feed structure and notching the edges of the radiator. For comparison, the performances of four other types of SPAs are also investigated numerically and verified experimentally. Given the information on the merits and weaknesses of these SPAs, antenna engineers can opt for the appropriate antenna with the desirable performance for their specific applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1093–1098, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23289
Microstrip‐fed circular slot antenna for circular polarization
Authors: Tseng Lin‐Yu , Han Tuan‐Yung 
Published: February 2008

AbstractA printed slot antenna with broadband circular polarization (CP) is presented. The proposed antenna is excited by an L‐shaped strip with a taper end, connected in series to a microstrip‐line‐fed located along the diagonal line of the circular‐slot. The measured results demonstrated a CP and impedance bandwidth of around 44% and 38%, respectively. It is noted that the CP bandwidth of 44% is much larger than those of antennas found in the literature. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1056–1058, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23290
Miniaturized hexaband meandered PIFA antenna using three meandered‐shaped slits
Authors: Tang I‐Tseng , Lin Ding‐Bing , Chen Wen‐Li , Horng Jui‐Hong 
Published: February 2008

AbstractA novel and compact hexaband meandered planar inverted‐F antenna with three meandered‐shaped slits is proposed, designed, and implemented. The proposed meandered PIFA antenna occupies a volume of 40 × 20 × 8 mm3, the top meandered patch radiator embedded with three simple meandered‐shaped slits, which separates the top meandered patch into four resonant paths to generate four resonant modes. The proposed hexaband antenna operates at covering the GSM‐900, GPS‐1575, DCS‐1800, PCS‐1900, ISM (2.400–2.4835 GHz), and WiMAX (2.305–2.69 GHz) bands for VSWR ≤ 2.5, and also more efficiently reduces 50% of the conventional meandered patch antenna size and broadens operational bandwidth. This compact low‐profile design shows characteristics of near‐omnidirectional radiation patterns with minimal hand effects, which is preferable for applications in wireless mobile communications. A good agreement between measurement and simulation is achieved. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1022–1025, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23292
Design procedure for active microwave filters using the high quality active negative capacitance circuit for RF low‐noise bandpass applications
Authors: Kaya Adnan 
Published: February 2008

AbstractThis article presents a new methodology based on active band pass filter. In the proposed design, a resonator consists of an active negative capacitor together with a conventional inductor represented. The active negative capacitor is made of a field‐effect transistor that exhibits negative capacitance and negative resistance. It can, therefore, compensate the loss of an inductor. Two pole active bandpass filter centered 1.3 GHz, with 3 dB bandwidth of 640 MHz, high gain 1.5 dB, including a very low‐noise active filter which exhibits a noise figure of 2.5 dB are realized in the fist part. Compared with the conventional BPF, the proposed design shows better gain, noise figure, and the return loss level. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1086–1093, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23296
Comment on “Compact Microstrip Bandpass Filter Using Composite Right/Left‐Handed Transmission Lines”
Authors: Perruisseau‐Carrier Julien 
Published: February 2008

Abstract© 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1132, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23302
Synthesis formulas for conductor‐backed coplanar waveguide
Authors: Yildiz Celal , Turkmen Mustafa 
Published: February 2008

AbstractSimple and accurate formulas are presented for the synthesis of conductor‐backed coplanar waveguide (CPW). These formulas are derived by applying function approximation and curve‐fitting technique to the respective quasi‐static analysis results. The results obtained from these formulas are compared with the results of quasi‐static analysis and experimental works available in the literature. Average percentage error is found to be better than 1% for 1086 conductor‐backed CPW samples having different electrical parameters and geometrical dimensions. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1115–1117, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23304
Dual band power amplifier in GaN technology
Authors: Colantonio Paolo , Giannini Franco , Giofrè Rocco , Piazzon Luca 
Published: February 2008

AbstractExperimental results of a simultaneous dual band high efficiency harmonic tuned power amplifier in GaN HEMT technology are presented. The amplifier has been realized in hybrid form and the measured results shown a peak of 53% and 46% of drain efficiency with 33 dBm and 32.5 dBm output power in the first (at 2.45 GHz) and second (at 3.3 GHz) bands, respectively. Moreover, a zero transmission condition has been obtained, resulting in a measured value ofS21lower than −15 dB at 2.8 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1040–1042, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23308
Regulation of granulosa and theca cell transcriptomes during ovarian antral follicle development
Authors: Skinner Michael K. , Schmidt Michelle , Savenkova Marina I. , Sadler‐Riggleman Ingrid , Nilsson Eric E. 
Published: February 2008

AbstractCoordinated interactions between ovarian granulosa and theca cells are required for female endocrine function and fertility. To elucidate these interactions the regulation of the granulosa and theca cell transcriptomes during bovine antral follicle development were investigated. Granulosa cells and theca cells were isolated from small (<5 mm), medium (5–10 mm), and large (>10 mm) antral bovine follicles. A microarray analysis of 24,000 bovine genes revealed that granulosa cells and theca cells each had gene sets specific to small, medium and large follicle cells. Transcripts regulated (i.e., minimally changed 1.5‐fold) during antral follicle development for the granulosa cells involved 446 genes and for theca cells 248 genes. Only 28 regulated genes were common to both granulosa and theca cells. Regulated genes were functionally categorized with a focus on growth factors and cytokines expressed and regulated by the two cell types. Candidate regulatory growth factor proteins mediating both paracrine and autocrine cell–cell interactions include macrophage inflammatory protein (MIP1 beta), teratocarcinoma‐derived growth factor 1 (TDGF1), stromal derived growth factor 1 (SDF1; i.e., CXCL12), growth differentiation factor 8 (GDF8), glia maturation factor gamma (GMFG), osteopontin (SPP1), angiopoietin 4 (ANGPT4), and chemokine ligands (CCL 2, 3, 5, and 8). The current study examined granulosa cell and theca cell regulated genes associated with bovine antral follicle development and identified candidate growth factors potentially involved in the regulation of cell–cell interactions required for ovarian function. Mol. Reprod. Dev. 75: 1457–1472, 2008. © 2008 Wiley‐Liss, Inc.
Motor unit recruitment and bursts of activity in the surface electromyogram during a sustained contraction
Authors: Riley Zachary A. , Terry Mary E. , Mendez‐Villanueva Alberto , Litsey Jane C. , Enoka Roger M. 
Published: February 2008

AbstractBursts of activity in the surface electromyogram (EMG) during a sustained contraction have been interpreted as corresponding to the transient recruitment of motor units, but this association has never been confirmed. The current study compared the timing of trains of action potentials discharged by single motor units during a sustained contraction with the bursts of activity detected in the surface EMG signal. The 20 motor units from 6 subjects [recruitment threshold, 35.3 ± 11.3% maximal voluntary contraction (MVC) force] that were detected with fine wire electrodes discharged 2–9 trains of action potentials (7.2 ± 5.6 s in duration) when recruited during a contraction that was sustained at a force below its recruitment threshold (target force, 25.4 ± 10.6% MVC force). High‐pass filtering the bipolar surface EMG signal improved its correlation with the single motor unit signal. An algorithm applied to the surface EMG was able to detect 75% of the trains of motor unit action potentials. The results indicate that bursts of activity in the surface EMG during a constant‐force contraction correspond to the transient recruitment of higher‐threshold motor units in healthy individuals, and these results could assist in the diagnosis and design of treatment in individuals who demonstrate deficits in motor unit activation. Muscle Nerve, 2008