bluuebunny/crossref_metadata_2025 huggingface dataset:
Sediment trapping by a tree belt: processes and consequences for sediment delivery
Authors: Leguédois Sophie , Ellis Tim W. , Hairsine Peter B. , Tongway David J.
Published: January 2008

Restoring belts of perennial vegetation in landscapes is widely recognized as a measure of improving landscape function. While there have been many studies of the transport of pollutants through grass filter strips, few have addressed sediment related processes through restored tree belts. In order to identify these processes and quantify their relative contribution to sediment trapping, a series of rainfall simulations was conducted on a 600 m2 hillslope comprising a pasture upslope of a 15 year old tree belt. Although the simulated events were extreme (average recurrence intervals ∼10 and 50 yr), the trapping efficiency of the tree belt was very high: at least 94% of the total mass of sediments was captured. All the size fractions were trapped with a minimum Sediment Trapping Ratio (STR) of 91% for the medium‐sized fragments. Fractions < 1·3 µm and > 182 µm were totally captured (STR = 100%). Through the joint analysis of sediment budgets and soil surface conditions, we identified different trapping processes. The main trapping process is the sedimentation (at least 62% of trapped sediment mass) with deposits in the backwater and as micro‐terraces within the tree belt. Modelling results show that the coarsest size fractions above 75 µm are preferentially deposited. Joint infiltration of water and sediments has also been noticed, however, this process alone cannot explain the selective trapping of the finest fractions. We suggest that the finest fractions transported by the overland flow may be trapped by adsorption on the abundant litter present within the tree belt. Copyright © 2008 John Wiley & Sons, Ltd.
Children's, adolescents', and adults' reference to goals to explain interpersonal actions
Authors: Pillow Bradford H. , Lovett Suzanne B. , Hill Valerie
Published: January 2008

This study investigated children's, adolescents', and adults' references to an actor's goals when explaining interpersonal actions. Participants were presented with eight brief stories containing a variety of social events and were asked to explain why the actor in each story performed the central action. Children, adolescents, and adults mentioned goals for most of the stories. Adults and adolescents mentioned psychological goals much more often than did children. Older children, adolescents, and adults mentioned complex psychological goals more often than did younger children. Younger children often mentioned instrumental or social goals. When making goal attributions, children, adolescents, and adults considered both the nature of the action and the social context in which it occurred. Participants mentioned psychological goals more often when explaining an antisocial action and social goals when explaining a prosocial action. Participants were also more likely to mention psychological goals when interpersonal events immediately preceding the central action were described. Thus, goals were offered as explanations for interpersonal actions by all age groups, but the type of goals mentioned varied by the age of the participant, the social context, and the valence of the action. Copyright © 2008 John Wiley & Sons, Ltd.
Proteome response in HT‐29 human colorectal cancer cells to two apoptosis‐inducing compounds with different mode of action
Authors: Winkelmann Isabel , Näßl Anna‐Maria , Daniel Hannelore , Wenzel Uwe
Published: January 2008

Flavone and camptothecin were both shown to potently induce apoptosis in HT‐29 human colon cancer cells. Whereas camptothecin acts on the basis of topoisomerase‐I inhibition, flavone appears to burst mitochondrial production of reactive oxygen species by increasing respiratory chain activity. In our study, we searched for similarities and differences in the proteome response of HT‐29 cells when treated with the two different compounds. The accessible proteome of HT‐29 cells was separated subsequent to the exposure to flavone or camptothecin by 2D‐polyacrylamide‐gel electrophoresis using pH‐gradients between 4 and 7 and 6 and 11 in the first dimension and proteins with changed expression level were identified by peptide mass fingerprints of tryptic digests of the protein spots. Whereas there was a high congruence with regard to the identities of regulated proteins and their grade of regulation, a number of spots changed specifically only in response to either flavone or camptothecin. Nuclear envelope proteins were specifically increased by camptothecin indicating the intervention of this drug with cell division processes. Increased levels of coproporphyrinogen III oxidase, involved in cytochrome synthesis, and ubiquinol‐cytochrome‐c reductase suggest adaptations to flavone in order to enable a higher substrate flux through the respiratory chain. In conclusion, HT‐29 cells respond to camptothecin and flavone with regulations of many proteins in a similar manner suggesting those alterations to be caused by apoptosis induction. Some protein regulations, however, were specific for each compound and point to the mechanism of their action. © 2008 Wiley‐Liss, Inc.
Nisin expression production from Lactococcus lactis in milk whey medium
Authors: de Arauz Luciana Juncioni , Jozala Angela Faustino , Pinheiro Gabriel Soares , Mazzola Priscila Gava , Júnior Adalberto Pessoa , Vessoni Penna Thereza Christina
Published: January 2008

BACKGROUND: Nisin is a commercially available bacteriocin produced by Lactococcus lactis ATCC 11454 and used as a natural agent in the biopreservation of food. In the current investigation, milk whey, a byproduct from dairy industries was used as a fermentation substrate for the production of nisin. Lactococcus lactis ATCC 11454 was developed in a rotary shaker (30 °C/36 h/100 rpm) using two different media with milk whey (i) without filtration, pH 6.8, adjusted with NaOH 2 mol L−1 and without pH adjustment, both autoclaved at 121 °C for 30 min, and (ii) filtrated (1.20 µm and 0.22 µm membrane filter). These cultures were transferred five times using 5 mL aliquots of broth culture for every new volume of the respective media.

RESULTS: The results showed that culture media composed of milk whey without filtration supplied L. lactis its adaptation needs better than filtrated milk whey. Nisin titers, in milk whey without filtration (pH adjusted), was 11120.13 mg L−1 in the second transfer, and up to 1628‐fold higher than the filtrated milk whey, 6.83 mg.L−1 obtained in the firstt transfer.

CONCLUSIONS: Biological processing of milk byproducts (milk whey) can be considered a profitable alternative, generating high‐value bioproducts and contributing to decreasing river disposals by dairy industries. Copyright © 2008 Society of Chemical Industry
Operational strategy for a partial nitritation–sequencing batch reactor treating urban landfill leachate to achieve a stable influent for an anammox reactor
Authors: Ganigué Ramon , López Helio , Ruscalleda Maël , Balaguer M. Dolors , Colprim Jesús
Published: January 2008

BACKGROUND: In recent years, new technologies have been developed to deal with streams with high nitrogen loads, most of them based on the anammox process. As a first step in this process, ammonium has to be partially oxidized to nitrite. This partial nitritation is usually carried out through the SHARON process. However, it can also be achieved using other configurations (sequencing batch reactor or biofilm airlift, among others). The aim of this paper is to compare two different feeding strategies (fed‐batch and step‐feed) for the operation of a partial nitritation–sequencing batch reactor (PN‐SBR) treating raw urban landfill leachate.

RESULTS: A PN‐SBR treating urban landfill leachate was started up and operated using two different feeding strategies: fed‐batch and step‐feed. When the experimental results were compared, it could be seen that during the step‐feed strategy the system was more stable and presented a better performance. In addition, a cycle profile evolution of the reactor in each strategy was carried out to study the dynamics of the main chemical compounds, as well as different physical parameters. The profiles were similar for the nitrogen compounds, but with a difference in behaviour of pH, inorganic carbon and oxygen uptake ratio, which could explain the better performance and stability of the step‐feed strategy.

CONCLUSIONS: This study has demonstrated that the step‐feed strategy is more suitable than the fed‐batch because it performs better overall, there is less fluctuation in its operation and it has higher effluent quality stabilization. Copyright © 2008 Society of Chemical Industry
A novel approach to precipitation series completion in climatological datasets: application to Andalusia
Authors: Ramos‐Calzado P. , Gómez‐Camacho J. , Pérez‐Bernal F. , Pita‐López M. F.
Published: January 2008

Complete monthly series of precipitation data have been generated for 932 stations run by the Instituto Nacional de Meteorología (INM) in Andalusia (Andalucía, southern region of Spain) and some adjacent areas for the period 1961–2000 using a new method for the estimation of missing data. The proposed method fills in the gaps in the climatological series for a target station using precipitation data from neighbouring stations with a similar precipitation pattern. Particular emphasis is made in the consideration of the precipitation data uncertainty. A set of possible estimates for the missing data are obtained assuming a linear relationship between the target station and the selected neighbour stations. The final imputed value is the median of the previously evaluated estimates distribution. This approach also provides the uncertainty of the missing data estimate. As an application, the suggested approach is used to obtain a precipitation map of Andalusia, as well as the average annual series for the examined period. Copyright © 2008 Royal Meteorological Society
Global summer monsoon rainy seasons
Authors: Zhang Suping , Wang Bin
Published: January 2008

A concise and objective definition of monsoon rainy season characteristics is proposed for worldwide monsoon regions. The result highlights six major summer monsoon rainy season domains and the mean dates of the local onset, peak and withdrawal phases of the summer monsoon rainy season. The onset phases occur progressively later poleward in the continental domains but primarily eastward in the oceanic monsoon regions. The rainy season retreats equatorward over the continental and oceanic monsoon regions. The length of the rainy season decreases poleward and shorter rainy season can also be found over the outskirts of warm water. Some exceptions exist in terms of the characteristics of rainy season, e.g. the westward advance of rainy season over North Africa and an apparently prolonged rainy season in the Korean peninsula. The results here are basically compatible with those obtained in previous studies on regional monsoons.

A definition of the seasonal wind overturning is proposed. Combining rainfall and winds, we stratify the global monsoon into strong and weak categories. The strong monsoons are typically in the regions with both concentration of summer rainfall and annual reversal of low‐level winds, while the weak monsoon features only a contrasting wet–dry season. Seemingly, some mid‐latitude regions with wind reversals are not monsoonal because of the reversals being opposite to the monsoon overturning and the rainfall patterns being more or less Mediterranean.

The comparison between the monsoon domains derived from Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) and the 40‐year European Centre for Medium‐Range Weather Forecasts Re‐Analysis (ERA‐40), the Japanese 25‐year Reanalysis (JRA‐25) and National Centers for Environmental Prediction (NCEP) datasets show good capabilities of the reanalyses in demarcation of the major monsoon rainy season domains in the tropics and subtropics. But the reanalyses are less realistic in the mid‐latitudes of Eurasia and North America. The result here provides the simple yet objective definitions of monsoon domain, onset, peak and withdrawal which are useful for validation of GCMs. Copyright © 2008 Royal Meteorological Society
Gauging the clinical significance of P‐glycoprotein‐mediated herb‐drug interactions: Comparative effects of St. John's wort, Echinacea, clarithromycin, and rifampin on digoxin pharmacokinetics
Authors: Gurley Bill J. , Swain Ashley , Williams D. Keith , Barone Gary , Battu Sunil K.
Published: January 2008

Concomitant administration of botanical supplements with drugs that are P‐glycoprotein (P‐gp) substrates may produce clinically significant herb‐drug interactions. This study evaluated the effects of St. John's wort and Echinacea on the pharmacokinetics of digoxin, a recognized P‐gp substrate. Eighteen healthy volunteers were randomly assigned to receive a standardized St. John's wort (300 mg three times daily) or Echinacea (267 mg three times daily) supplement for 14 days, followed by a 30‐day washout period. Subjects were also randomized to receive rifampin (300 mg twice daily, 7 days) and clarithromycin (500 mg twice daily, 7 days) as positive controls for P‐gp induction and inhibition, respectively. Digoxin (Lanoxin® 0.25 mg) was administered orally before and after each supplementation and control period. Serial digoxin plasma concentrations were obtained over 24 h and analyzed by chemiluminescent immunoassay. Comparisons of area under the curve (AUC)(0–3), AUC(0–24), elimination half‐life, and maximum serum concentration were used to assess the effects of St. John's wort, Echinacea, rifampin, and clarithromycin on digoxin disposition. St. John's wort and rifampin both produced significant reductions (p < 0.05) in AUC(0–3), AUC(0–24), and Cmax, while clarithromycin increased these parameters significantly (p < 0.05). Echinacea supplementation did not affect digoxin pharmacokinetics. Clinically significant P‐gp‐mediated herb‐drug interactions are more likely to occur with St. John's wort than with Echinacea.
Analysis of conductor loss in interdigital capacitor based measurement of dielectric constant of ferroelectric thin film
Authors: Wang P. , Tan C. Y. , Ma Y. G. , Cheng W. N. , Ong C. K.
Published: January 2008

A procedure to include conductor loss in interdigital capacitor based dielectric constant measurements is proposed. The effect of conductor loss and contact resistance can be regarded as a series resistor connected to the interdigital capacitor. If the thickness of the conductor film is known, the conductor loss could be calculated and subtracted from the measurement results. In the frequency range where the dielectric constant of the material in test does not change with frequency, the conductor loss could also be obtained by measuring the frequency dependence of the impedance of the interdigital capacitor. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 566–568, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23141
The realization and analysis of pattern/polarization diversity in multiple input multiple output array
Authors: Chae Sung Ho , Yoon Hyeong‐Sik , Park Seong‐Ook
Published: January 2008

This article proposes the pattern/polarization diversity array for multiple input multiple output applications by applying vertical and horizontal excitation. We show that pattern and polarization of antenna are changed due to vertical feeding. Then, we attempt to realize the two antenna diversity array by using different feeding method. As a result, the correlation factors with respect to the pattern and polarization diversity are investigated. Finally, the analysis of the diversity system in the view point of capacity is presented. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 561–566, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23142
A novel method of detecting HIV/AIDS using microwaves
Authors: Lonappan Anil , Thomas Vinu , Bindu G. , Jacob Joe , Rajasekaran C. , Mathew K. T.
Published: January 2008

HIV/AIDS is one of the most destructive epidemics in ever recorded history claims an estimated 2.4–3.3 million lives every year. Even though there is no treatment for this pandemic Elisa and Western Blot tests are the only tests currently available for detecting HIV/AIDS. This article proposes a new method of detecting HIV/AIDS based on the measurement of the dielectric properties of blood at the microwave frequencies. The measurements were made at the S‐band of microwave frequency using rectangular cavity perturbation technique with the samples of blood from healthy donors as well as from HIV/AIDS patients. An appreciable change is observed in the dielectric properties of patient samples than with the normal healthy samples and these measurements were in good agreement with clinical results. This measurement is an alternative in vitro method of diagnosing HIV/AIDS using microwaves. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 557–561, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23143
A novel uniplanar compact EBG incorporated with interdigital structure
Authors: Lin Bao‐Qin , Wen Xi
Published: January 2008

A novel uniplanar electromagnetic Band‐Gap (EBG) scheme is presented for size reduction, the proposed structure can be considered as an ameliorated uniplanar compact EBG (UC‐EBG) incorporated with interdigital structure which enlarges the fringe capacitance to compress the overall size of unit cell. Its design is detailed in this article and several simulation and experimental results are presented, the properties of the proposed ID‐UC‐EBG are examined when compared with that of the conventional UC‐EBG. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 555–557, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23144
UWB corner‐slot antenna
Authors: Pidre J. M. , Vera‐Isasa M. , Santalla V. , de Lorenzo E.
Published: January 2008

A new bended slot antenna for ultra‐wideband applications is proposed in this article. A prototype has been fabricated and results show that the proposed design exhibits very low voltage standing wave ratio (<1.5) and broadside radiation pattern from 3 to 9 GHz. By processing frequency domain measurements with an IFFT algorithm, the time domain performance of the antenna has been evaluated. The fidelity is better than 0.98 for boresight direction and greater than 0.82 for the rest. All this results reveal that the antenna as an excellent candidate for ultra short microwave pulse radiation. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 663–665, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23146
Design and experimental investigation on novel microstrip band‐pass filters
Authors: Passi V. , Ghafouri‐Shiraz H.
Published: January 2008

Two novel fifth order, 2.5‐GHz bandpass filters, with 4% bandwidths were designed and fabricated. The filters which are modified versions of the hairpin filter are designed empirically using the optimization feature in microwave simulation software. We found good agreement between the simulated and measured responses of these filters, validating the optimization design methodology. The original hairpin filter has also been fabricated, and it is shown that the novel filters have good performance in comparison. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 655–658, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23152
Miniaturized hairpin resonator filters using dielectric ceramic substrates
Authors: Shen Chun‐Hsu , Huang Cheng‐Liang
Published: January 2008

This article describes the band‐pass filters using miniaturized hairpin resonators with parallel coupled lines. Two microwave dielectric ceramic substrates (with dielectric constants of 9.7 and 20, respectively) have been adopted to realize small chip size. The design of the band‐pass filters using miniaturized hairpin resonators are simulated by IE3D simulator. A precise planar band‐pass filter has been fabricated using the screen printing technique. The response of the fabricated filters using Al2O3 (εr = 9.7, Q × f = 35,000 GHz) and 0.94 MgTiO3 − 0.06 CaTiO3 + 0.25 wt%V2O5 (hereafter referred to as 94MCT + V2O5) (εr = 20, Q × f = 62,000 GHz, τf = −2.26 ppm/°C) are designed at a center frequency of 900 MHz. A fractional bandwidth of 5.7% with −2.6‐dB insertion loss and 19‐dB attenuation had been achieved with a chip size of 14.6 × 11.9 mm2. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 620–624, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23153
A microstrip dual‐band bandpass filter with reduced size and improved stopband characteristics
Authors: Guan Xuehui , Ma Zhewang , Cai Peng , Anada Tetsuo , Hagiwara Gen
Published: January 2008

A novel compact microstrip dual‐band bandpass filter (BPF) is developed with remarkably improved stopband characteristics. Two‐square open‐loop resonators are embedded in a U‐shaped resonator to achieve a significant size reduction of the filter. Meanwhile, a cross‐coupling between nonadjacent resonators is exploited to produce multiple transmission zeros in the stopbands of the filter. As a consequence, wide stopbands with sharp and large attenuations are obtained. Theoretical and measured frequency responses of the designed filter show a good agreement.© 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 618–620, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23154
A new approach to the design of a compact high efficiency active integrated antenna
Authors: Ooi S. F. , Lee S. K. , Sambell A. , Korolkiewicz E. , Scott S.
Published: January 2008

In this letter, two active integrated antenna (AIA) circuits employing an H‐shaped patch antenna operating at 2.45 GHz are presented. In the first design a probe feed position on the antenna is found to give an input impedance of 50 Ω at the fundamental frequency. For the second design a probe feed position is found to give the optimum impedance at the fundamental frequency. Hence the load matching network is eliminated. Each circuit achieved a measured power added efficiency (PAE) of over 67%. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 585–589, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23156
Miniaturized 5.2 GHz notched UWB CPW‐FED antenna using dual reverse split trapezoid slots
Authors: Tang I.‐T. , Lin Ding‐Bing , Liou Geng‐Hong , Horng Jui‐Hong
Published: January 2008

A novel compact 5.2 GHz notched ultra‐wideband (UWB) CPW‐fed monopole antenna using dual reverse split trapezoid slots which has small area of (16 × 17 mm2) is proposed. The designed antenna operates over 3–11 GHz for VSWR ≤ 2 including the WLAN band notched at the vicinity of 5.2 GHz. The dual reverse split trapezoid slots are employed effectively for notching unwanted frequency band such as that for WLAN service, since it can be implemented with a small dimension and in a high Q operation similarly to the conventional strip‐type dual reverse split ring resonator (SRR). Based on the simulated and measured results, a band notched UWB antenna using dual reverse split trapezoid slots is very effective in rejecting unwanted frequency in terms of its selectivity. Good monopole‐like radiation patterns and antenna gains have also been obtained. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 652–655, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23157
Analysis of a quad‐section SIR
Authors: Packiaraj D. , Ramesh M. , Kalghatgi A. T.
Published: January 2008

This paper gives the closed form expressions for the resonator length and spurious frequencies of a quad‐section stepped impedance resonator (QSIR) in terms of impedance ratios. An experimental filter using QSIRs at 2.4 GHz has been designed and tested to verify the analysis. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 649–652, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23158
Research of the measuring technique of numerical aperture of optical fiber using near infrared light
Authors: Chen Der‐Chin
Published: January 2008

In this paper, we demonstrate a new technology in which we use the near infrared (NIR) electro‐optical device and projection method to measure the numerical aperture (NA) of NIR fiber. Using the optical coupler to let the NIR light enter into an optical fiber, the projection pattern is then measured at the distance of L, where the length L and the diameter W of the projection pattern area on screen is recorded. The NA of NIR fiber is computed from the recorded data. This is a fast method for testing NA and can measure the NA deviation to an accuracy of 0.01. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 582–584, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23161
A composed right/left‐handed waveguide with open‐ended corrugations for backward‐to‐forward leaky‐wave antenna application
Authors: Pan Pan , Meng Fan‐Yi , Wu Qun
Published: January 2008

A novel composed right/left‐handed (CRLH) rectangular waveguide (RWG) is presented. It is periodically loaded with open‐ended corrugations, which allow energy radiating from them. Compared with previously referred left‐handed (LH) waveguides, this proposed structure is more effective for leaky‐wave antennas (LWAs) design. To determine the dispersion property, an equivalent circuit is given. Based on the CRLH RWG, a LWA is achieved and analyzed by full wave simulation, which supports the backward‐to‐forward beam scanning by frequency above 7.45 GHz. The obtained propagation and radiation results are in good agreement with theoretical suggestions. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 579–582, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23162
Optimization of cascode configuration in CMOS low‐noise amplifier
Authors: Song Ickhyun , Koo Minsuk , Jung Hakchul , Jhon Hee‐Sauk , Shin Hyungcheol
Published: January 2008

In this paper, design consideration of the cascode configuration in low‐noise amplifiers (LNA) using 0.13‐μm CMOS technology is presented. Performance factors of LNAs such as signal power gain, noise factor, and power consumption are analytically expressed in device parameters from its small‐signal equivalent circuit. The effect of the common‐gate transistor in each performance factor is evaluated at the target frequency of 17‐GHz ISM band. At this frequency, power gain and noise factor are degraded, which result from the common‐gate transistor. Figure of merit of LNAs is also optimized. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 646–649, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23163
A varactorless CMOS direct‐injection locked frequency divider
Authors: Jang S.‐L. , Liu C.‐C.
Published: January 2008

This paper presents a new integrated direct‐injection locked frequency (ILFD) with the capability of quadrature generation. The circuit consists of a quadrature VCO, based on the cross‐coupling of two differential LC‐tank VCOs and with the coupling transistors placed in parallel with the switch transistors, and two direct injection MOSFETs. No varactors are used, and feedback is applied for frequency tuning. The circuit is implemented using a standard 0.35 μm CMOS process. Measurement results show that at the supply voltage of 3.3 V, the core power consumption is 27 mW. The free‐running ILFD is tunable from 1.5 to 1.98 GHz and the locking range is 2.92–4.26 GHz at 0 dBm. The measured phase noise of free‐running ILFD is −118.3 dBc/Hz while the locked quadrature output phase noise is −126.7 dBc/Hz at 1 MHz offset frequency from the oscillation frequency of 1.98 GHz, which is 8.4 dB lower than the free running ILFD. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 608–611, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23165
Bridged‐shunt‐series peaking technique for a 3.1 10.6 GHz ultra‐wideband CMOS low noise amplifier
Authors: Lin Yu‐Liang , Liao Hsien‐Yuan , Chiou Hwann‐Kaeo
Published: January 2008

An ultra‐wideband 3.1–10.6‐GHz low noise amplifier (LNA) adopting inductive peaking technique for bandwidth extension is presented. Fabricated in a 0.18‐μm CMOS process, the proposed circuit can both satisfy the maximum bandwidth and the maximally flat response. The feedback resistor provides good input match while contributing a small amount in noise figure degradation. The presented LNA achieves a maximum power gain of 14.1 dB within a 3‐dB bandwidth from 2.2 to 11 GHz and a good noise figure from 3.4 to 4.5 dB in the entire UWB band, and an IIP3 better than −3 dBm while drawing 30 mW from a 1.5‐V supply. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 575–578, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23166
Efficient finite element solution of low‐frequency scattering problems via anisotropic metamaterial layers
Authors: Ozgun Ozlem , Kuzuoglu Mustafa
Published: January 2008

We introduce a new technique which remedies the drawbacks in the Finite Element solution of low‐frequency electromagnetic scattering problems, through the usage of an anisotropic metamaterial layer which is designed by employing the coordinate transformation approach. The usual finite element method should utilize a “challenging” mesh generation scheme to accurately simulate the “small” objects in scattering problems; on the contrary, the proposed technique provides a considerable reduction in the number of unknowns, and requires a more convenient and simpler mesh structure inside the computational domain. The most interesting feature of the proposed method is its capability to handle arbitrarily shaped “small” scatterers by using a “single” mesh and by modifying only the constitutive parameters inside the matamaterial layer. We report some numerical results for two‐dimensional electromagnetic scattering problems. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 639–646, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23167
Simulation and timing performances of integrated waveguides for ultra‐high speed interconnects
Authors: Urbano Davide , Arnieri Emilio , Cappuccino Gregorio , Amendola Giandomenico
Published: January 2008

Integrated circuit technology is causing system designs to move toward complex architectures, requiring communication channels characterized by ever increasing capacity. In this context, classical metallic interconnects become a bottleneck, owing to the power consumption, crosstalk, and signal integrity issues. Substrate integrated waveguides (SIW) are a potential technological solution to overcome traditional interconnect limitations. In this article, the authors present frequency and time domain analysis of these structures, comparing two different SIW structures in terms of time and signal dispersion performances. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 666–672, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23168
Design of high‐performance broadband multisection symmetrical 3‐DB directional couplers
Authors: Gruszczynski Slawomir , Wincza Krzysztof
Published: January 2008

The influence of discontinuity effects on the performance of symmetrical multisection coupled‐line directional couplers designed in a stripline technique has been comprehensively investigated, for the first time. It has been shown that the connections between coupled‐line sections introduce parasitic reactances which deteriorate the isolations and return losses of designed couplers and also that the recently developed method of capacitive compensation can be applied to improve couplers' performance. A three‐section symmetrical 3‐dB directional coupler has been designed and measured. The measurement results validate the presented analyses. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 636–638, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23169
Effect of cylinder spacing on reflection and propagation of substrate‐integrated waveguide
Authors: Wang Lei , Che Wenquan , Wang Chao , Chang Yumei , Wang Zhanxian
Published: January 2008

The effects of cylinder spacing on the reflection and propagation of substrate‐integrated waveguide (SIW) are investigated in this article. The reflection and propagation characteristics of SIW are simulated with HFSS in cases of different cylinder spacings. The simulation results show that, the cylinder spacing of SIW has much flexibility of selection, the return loss and insertion loss can be kept almost unchanged, provided that the cylinder spacings W <λ/10. The propagation constants in cases of different cylinder spacing are calculated, little change can be observed if W <λ/10. In addition, the leakage losses of the SIW in case of different cylinder spacing is calculated, same conclusion can be observed, i.e., the leakage loss is relatively small if the cylinder spacing W <λ/10. This observation is interesting and useful for practical engineering design of SIW‐based circuits. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 604–608, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23171
Bandwidth‐enhanced internal PIFA with a coupling feed for quad‐band operation in the mobile phone
Authors: Wong Kin‐Lu , Huang Chih‐Hong
Published: January 2008

A novel bandwidth‐enhanced internal planar inverted‐F antenna (PIFA) for quad‐band operation in the mobile phone is presented. The proposed PIFA is capacitively excited using a coupling feed, which leads to a dual‐resonance excitation in the antenna's lower band at about 900 MHz and a wide‐band resonant mode excitation at about 1800 MHz. This makes the operating bandwidths of both the antenna's lower and upper bands larger than 20% (3:1 VSWR), thus easily covering GSM850/900 and DCS/PCS operation. In addition, with quad‐band operation obtained, the proposed PIFA occupies a small volume of 5 × 6 × 60 mm3 or 1.8 cm3 only. Details of the proposed PIFA are described, and results of fabricated prototypes are presented and discussed. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 683–687, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23175
Parallel‐coupled bandpass filter with improved rejection slope using δ‐offset length
Authors: Soh Johnson , Teck Chew Siou , Ooi Ban‐Leong
Published: January 2008

In this article, a novel method to improve the rejection of edge coupled filters by perturbing the coupled line sections by a length, δ, is introduced. This gives controls over the null position between the fundamental and 1st harmonic of the filter which results in a steeper rejection slope by shifting this null closer to the centre frequency. A 4th order 5 GHz band‐pass filter is designed and tested. Measured results show an improvement of about 9 dB at 6 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 680–683, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23176
Synthetic asymptote formulas of asymmetric edge‐coupled striplines
Authors: Tang Wanchun , Yu Zhengyong , Chen Xuemei
Published: January 2008

Simple CAD formulas are obtained in this article for the even–odd mode capacitances and characteristic impedances of asymmetric edge‐coupled stripline via synthetic asymptote. Compared with the numerical results, the average error is less than 2%. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 706–708, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23178
A one‐piece flat‐plate dipole antenna for dual‐band WLAN operation
Authors: Su Saou‐Wen , Chou Jui‐Hung , Liu Yung‐Tao
Published: January 2008

A simple, one‐piece, flat‐plate dipole antenna suitable for dual‐band WLAN applications is presented. The antenna is structured to be of an L‐shape to fit in corners of possible wireless electronics devices. The two radiating arms of the dipole antenna are further short‐circuited through a narrow shorting strip at the corners, making it possible for the antenna to be manufactured by stamping a single, flat metal plate only one time. That is, the proposed antenna in the mass‐production phase can be at lower cost. In addition, by cutting an L‐shaped slit at proper location in each radiating arm, a dual‐band operation can easily be obtained. The design prototype of the antenna in the 2.4/5.2 GHz bands is discussed in detail in the article. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 678–680, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23179
Integrated planar spiral inductors with CoFe and NiFe ferromagnetic layer
Authors: Kim GyoungBum , Cha Seung‐Yong , Hyun Eun‐Kyung , Jung YoungChai , Choi YoonSuk , Rieh Jae‐Sung , Lee Seong‐Rae , Hwang SungWoo
Published: January 2008

Inductance increase up to 28% was obtained for on‐chip spiral inductors by employing DC‐sputtered CoFe and NiFe ferromagnetic (FM) layer on top of the spirals. It was also observed that slit‐patterned FM layers exhibited better quality factors than blanket FM layers, leading to values comparable to that of the inductors without FM layer. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 676–678, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23180
Fresnel zone plate antenna with hexagonal‐cut zones
Authors: Stout‐Grandy S. M. , Petosa A. , Minin I. V. , Minin O. V. , Wight J. S.
Published: January 2008

A novel Fresnel zone plate antenna (FZPA) with hexagonal‐cut zones is presented. This new structure was simulated at 30 GHz using a finite‐difference time‐domain software to study its gain and sidelobe levels in relation to the standard circular FZPA and the hexagonal FZPA. Several prototypes were built and tested to verify the simulations. It was found that the FZPA with rotated alternating hexagonal‐cut zones provides the ability to control the shape and location of the sidelobes while still maintaining the benefits of the hexagonal shape in terms of array packing. Also, this new structure has an improved sidelobe level over the standard version. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 672–676, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23183
Passively Q‐switched erbium‐doped fiber laser based on nonlinear polarization rotation
Authors: Zhang Zuxing , Sang Minghuang , Ye Zhiqing , Nie Yiyou
Published: January 2008

We have experimentally demonstrated an all‐fiber passively Q‐switched Erbium‐doped fiber (EDF) ring laser based on nonlinear polarization rotation. By incorporating a long section of single‐mode fiber and a polarization‐dependent isolator into the EDF ring laser, the intensity‐dependent transmission due to the effect of nonlinear polarization rotation can be implemented, which can act as an artificial saturable absorber for Q‐switching. Such a passively Q‐switched ring laser has the simple and all‐fiber configuration. In addition, passively harmonic mode‐locking and chaotic pulses are also generated from the EDF ring laser. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 694–696, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23185
On the interpolation of the frequency variations of the MoM‐PO impedance matrix over a wide bandwidth
Authors: Karwowski Andrzej , Noga Artur
Published: January 2008

A possibility of generating wide‐band data from MoM‐PO hybrid formulation by frequency interpolation of the impedance matrix is examined with particular attention given to a simple interpolation scheme originally proposed for the MoM impedance matrix, employing three uniformly spaced frequency nodes forming a sliding window over the desired band. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 738–741, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23190
Elliptically shaped ultra‐wideband patch antenna with band‐notch features
Authors: Yuan Tao , Qiu Cheng‐Wei , Li Le‐Wei , Seng Leong Mook , Zhang Qun
Published: January 2008

A series of ultra‐wideband antenna using an elliptically curved patch is investigated. The band‐notch feature is realized by cutting off a bended slot, which can be tuned. S11 is controllable by the length of the tunable slot. The antenna exhibits good omnidirectional performance across the operation bandwidth. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 736–738, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23191
Perfectly matched layers backed with the first order impedance boundary condition for the time‐domain finite‐element solution of waveguide problems
Authors: Du L. , Chen R.S. , Ye Z.B.
Published: January 2008

The first order impedance boundary condition (the first order ABC) is combined with the perfectly matched layer (PML) for the time‐domain finite‐element (TDFE) simulation of waveguide problems. The formulation is validated by the numerical simulations of waveguide problems. Numerical results clearly show that the PML backed with the first order impedance boundary condition performs better than the PML backed with the perfect electrically conducting (PEC) wall when used to absorb the propagating wave. In the same situation, PML terminated with the first order impedance boundary condition can reduce about 10 dB of the reflection errors compared with that obtained from the PML terminated by PEC wall. Therefore, the proposed boundary conduction can reduce the number of the unknowns and provide an effective mesh truncation for the TDFEM solution of waveguide problems. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 838–843, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23192
An LC‐tank injection locked frequency divider with record locking range percentage
Authors: Jang Sheng‐Lyang , Chen Fei‐Hung , Lee Chien‐Feng , Juang M.‐H.
Published: January 2008

This article presents a wide locking range injection locked frequency divider (ILFD) implemented using a standard 0.18‐μm CMOS process. The ILFD consists of a double‐cross‐coupled VCO and an injection MOS for coupling injection signal to the resonator. At the supply voltage of 1.8 V, the free‐running ILFD is tunable from 4.46 to 4.91 GHz. At the injection power of 0 dBm, the locking range of ILFD is tunable from 6.2 to 11 GHz. The percentage of ILFD locking range is 55.8%, which is the highest among similar published LC‐tank ILFDs. The phase noise of the ILFD can track with the injection source. The ILFD has been applied to form a quadrature ILFD and an on‐chip VCO has been designed to verify the function of the quadrature ILFD. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 806–809, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23193
A dual‐frequency microstrip antenna based on an unbalanced composite right/left‐handed transmission line
Authors: Jie Xiaoyong , Luo Chunrong , Zhao Xiaopeng
Published: January 2008

An unbalanced composite right/left‐handed transmission line structure is used for the design of a novel dual‐frequency microstrip antenna operating at X band. It is shown that the antenna has a very similar performance in both the operating modes to that of a conventional microstrip patch antenna (MPA) with respect to radiating characteristics. Moreover, the measured −10 dB bandwidth and gain for the proposed antenna are improved. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 767–771, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23195
Investigations on the microwave properties of electropolymerised polyaniline thin film
Authors: Vhanakhande B. B. , Jadhav S. V. , Kulkarni D. C. , Puri Vijaya
Published: January 2008

This study reports the X‐and Ku‐band microwave transmittance, reflectance, conductivity, and shielding effectiveness of nano structured electropolymerised polyaniline (PANI) thin films on stainless steel. Waveguide reflectometer method has been used for the microwave studies. Microwave conductivity varies between 0.85 and 0.18 S/cm. PANI thin films have better shielding effectiveness in Ku‐band than in X‐band. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 761–766, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23196
Novel dual‐mode dual‐band bandpass filter using nested microstrip meander‐loop resonators
Authors: Dai Xi‐Wang , Liang Chang‐Hong , Chen Zhi‐Xi
Published: January 2008

A novel dual‐mode dual‐band bandpass filter using nested meander‐loop resonators is proposed in this article. The new filter structure is small and convenient to change the higher passband frequency. Several finite attenuation poles in stopbands are realized to improve the selectivity of the proposed bandpass filter. The filter is evaluated by experiment and simulation with very good agreement. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 836–838, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23199
Solution of electromagnetic scattering problems by transformation into high order impedance boundary condition
Authors: Tezel Necmi Serkan
Published: January 2008

In this study, electromagnetic scattering from inhomogeneous impedance cylinder of arbitrary shape have been solved by means of transformation of problem into equivalent problem, that is scattering from circle represented by high order inhomogeneous impedance boundary condition (IBC). High order impedance functions are determined by using shape of object and its surface impedance. Then, equivalent problem is solved by means of series expansion method. This transformation makes the problem simple formulation, which can be solved computational effectively. Results and computational times obtained by transform method and those obtained by Method of Moment (MoM) technique are compared. Good agreements are observed in results. It is also observed that transform method needs less computational time than MoM method. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 832–836, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23200
Ultra wideband planar antenna with spurline for subband rejection
Authors: Abbosh A. M.
Published: January 2008

The design of a compact ultra wideband planar antenna with subband rejection capability is presented. A spurline is incorporated in the microstrip feeder of the antenna to act as a bandstop filter, hence enabling the rejection of any undesired band within the passband of the antenna. Results of a parametric investigation are presented to show effect of the spurline parameters on width of the rejected subband. The investigation shows that increasing the slot and spurline widths increases width of the rejected subband. Three samples of the proposed antenna were designed and manufactured. One of the developed antennas does not contain spurline, whereas the other two contain spurlines with different dimensions. The designed antennas feature a compact size of 25 mm × 25 mm. Results of the simulation and measurement show that the designed antennas have a bandwidth from 3 GHz to more than 11 GHz. The results also show that the use of the spurlines in the microstrip feeder of the antennas efficiently rejects any undesired subband, such as the 4.9–5.9 GHz band assigned for IEEE802.11a and HIPERLAN/2. The gain of the antennas with spurline is about 2.5 dB at the passband, while it is less than −15 dB at the rejected subband. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 725–728, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23205