bluuebunny/crossref_metadata_2025 huggingface dataset:
Planar ultra wideband inphase power divider
Authors: Abbosh A. M.
Published: March 2009

A planar inphase power divider, which has ultra wideband performance, is presented. The proposed device utilizes a T‐microstrip junction combined with an electromagnetic coupling between a slotted ground plane and an elliptical patch at the centre of the T‐junction. A resistor is also used to enhance the isolation between the output ports of the power divider. The simulated and measured return losses at the three ports of the device, isolation between its output ports, and phase stability of the output signals prove the ultra wideband performance of the presented device. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1185–1188, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24272
Diversity performance of body communication channels using switching parasitic disk‐loaded monopole array antenna
Authors: Kamarudin M. R. , Hall P. S.
Published: March 2009

In the cellular systems diversity reception techniques such as space, time, frequency, polarization, and pattern diversity are widely used to minimize or mitigate the effect of multipath fading due to scattering, diffraction, and reflection of the transmitted signal. Practically, these methods can be applied either at the base station or at the mobile terminal. In the on‐body environment, fading has also been found to be significance. Space diversity has been useful in such channels. In this article, a switching parasitic disk‐loaded monopole array antenna (also called pattern diversity antenna) was used to investigate diversity performance in on‐body channels. There were five body channels that have been investigated that are belt‐to‐chest, belt‐to‐wrist, belt‐to‐ankle, belt‐to‐head, and belt‐to‐back channels. The diversity data was analyzed using a switched diversity combining method. Diversity gain has been measured at outage of 1% and 10% for five on‐body channels. The results show significance gains are achieved for nonline‐of‐sight channels especially the ankle and wrist channels which have involved lots of antenna movement. In contrast, very little gain is obtained for line‐of‐sight channel particularly for the chest channel as only one beam was used for most of the time. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1157–1161, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24274
Particle swarm intelligence applied to determination of the feasible design target for a low‐noise amplifier
Authors: Güneş Filiz , Özkaya Ufuk , Demirel Salih
Published: March 2009

In this work, feasible design target space is presented as an optimization problem for a basic low‐noise amplifier and solved by using particle swarm optimization (PSO). This feasible design space consists of {Noise Figure F, Input VSWR Vi, Gain GT} triplets and their source ZS and load ZL termination couples. Worked examples are preented for the two high technology transistor and results are compared with the ones obtained from the device performance characterization Gunes et al., IEEE Proc Circ Devices Syst 141 (1994) 337–344. Excellent agreement is observed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1214–1218, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24276
A dual‐polarized printed UWB antenna
Authors: Yunlong Cai , Feng Zhenghe
Published: March 2009

A dual‐polarized PES‐monopole UWB antenna is proposed. It is coplanar and compact, and the dimension is only 45 *30 *1 mm3. The two equivalent antenna ports are orthogonal, and the isolation between the two ports is 13–20 dB. The antenna is dual‐polarized. The cross‐polarization of each port is low over UWB frequency.© 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1177–1180, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24279
Resonance transmission through electromagnetic crystals consisting of metal strips
Authors: Bing Hwang Ruey
Published: March 2009

In this letter, we present frequency‐selective transmission of a 2D (two‐dimensionally) electromagnetic (EM) crystal. Such a 2D EM crystal consists of a finite stack of one‐dimensionally metal‐strip gratings. The rigorous mathematical formulation using the mode‐matching method incorporating the Floquet solution was employed to calculate the scattering and guiding characteristics of the structure under consideration. Additionally, the experimental studies were also carried out to verify the numerical results. Significantly, the correlation between frequency‐selective transmission and the Fabry‐Perot resonance was clarified. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1209–1212, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24280
Hybrid of monopole and dipole antennas for concurrent 2.4‐ and 5‐GHz WLAN access point
Authors: Chou Jui‐Hung , Su Saou‐Wen
Published: March 2009

A novel hybrid of a 2.4‐GHz monopole antenna and a 5‐GHz dipole antenna is presented to provide concurrent 2.4 and 5 GHz band operation for access‐point applications. The two antennas are arranged in a collinear structure and printed on a compact dielectric substrate with dimensions 12 mm × 60 mm. The monopole antenna has a meandered radiating strip and is short‐circuited to a small ground plane through a shorting strip. The dipole antenna includes two sub‐dipoles at the opposite side of a narrow ground plane and fed by a simple T‐junction microstrip‐line network. The two antennas are closely set with a distance of 1 mm only, yet good port isolation (S21) well below −20 dB can be obtained. With a low profile, the proposed design can easily fit into the casing of some standard access points and allow the 2.4 and 5 GHz band signals to be simultaneously received or transmitted with no external diplexer required. Good omnidirectional radiation has been observed too. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1206–1209, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24281
A differential VCO using the drain‐connected‐to‐body MOSFET
Authors: Jang Sheng‐Lyang , Chang Chia‐Wei , Suchen Ming‐Hsiang , Shen Kuan‐Chun
Published: March 2009

A new differential voltage‐controlled oscillator (VCO) is designed and implemented in a 0.13 μm CMOS 1P8M process. The designed circuit topology is an all nMOS LC‐tank VCO, and a drain‐connected‐to‐body MOSFET is used to enhance the VCO performance. At the supply voltage of 1.0 V, the output phase noise of the VCO is −109.66 dBc/Hz at 1 MHz offset frequency from the carrier frequency of 13.64 GHz, and the figure of merit is −187.15 dBc/Hz. Total power consumption is 3.3 mW. Tuning range is about 270 MHz, from 13.63 to 13.9 GHz, while the control voltage was tuned from 0 to 1.0 V.© 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1174–1177, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24282
Design of an I‐band low phase noise oscillator using a new hair‐pin resonator
Authors: Yoon Ki‐Cheol , Lee Hyun‐Wook , Park Jung‐Geun , Kim Ki‐Byoung , Lee Jong‐Chul
Published: March 2009

In this article, a new high Q resonator is presented and it is applied to the design of an I‐band oscillator. The measurement of the resonator itself shows that it provides a higher loaded quality factor when compared with the spiral‐resonator. The oscillator is designed to be operated at 10 GHz using the new resonator to confirm the phase noise performance. The measurement results for the new hair‐pin resonator oscillator show the output power of 8.18 dBm and the phase noise of −103.48 dBc/Hz at 100 kHz offset. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1172–1174, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24283
Photonic generation of microwave/millimeter‐wave sources without cavity or modulation using fiber stimulated Brillouin scattering
Authors: Gao Shiming , Fu Hongyan , Gao Ying
Published: March 2009

A simple photonic scheme is presented to generate microwave/mm‐wave sources by utilizing the optical heterodyne technique between an optical carrier and its Stokes light coming from stimulated Brillouin scattering (SBS) in optical fibers. Stable microwave sources with the frequencies of about 10.56 and 21.71 GHz are experimentally realized using the first‐ and second‐order SBS frequency shifts based on standard single‐mode fibers. This scheme is laser cavity or modulation free and of frequency‐multiplied capacity to achieve higher microwave and millimeter‐wave sources. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1203–1206, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24285
Propagation and radiation characteristics of dielectric‐loaded axial‐mode helical antenna
Authors: Chandra Gupta Ramesh , Singh S. P.
Published: March 2009

This article presents theoretical and/or experimental study of the propagation and radiation characteristics of dielectric‐loaded axial‐mode helical antenna at 8.985 and 10.0 GHz. Characteristic equations for the sheath helix model are derived for three different dielectric loadings viz. loading with two coaxial dielectric layers, single dielectric layer, and air. These equations are solved for the propagation constant and hence the phase velocity for n = 1 higher order spatial harmonic mode. The variation in phase velocity with wavelength normalized helix circumference is studied for different ratio of outer to inner helix radii, ratio of outer to inner radii of the dielectric tube containing a solid dielectric cylinder inside the helix, and the dielectric constant of the dielectrics used. The results for variation in phase velocity of the wave for n = 1 mode propagating in sheath helix with wavelength normalized helix circumference for pitch angle of 7° are compared with the available theoretical data. The theoretical expression for the radiation field of the helical antenna is obtained through the application of magnetic vector potential for n = 1 mode. The theoretical Eθand Eϕpatterns of the helical antenna with three different dielectric loadings are compared among themselves and also with respective experimental results at 8.985 and 10.0 GHz in X‐band. The gain, input VSWR, and axial ratio of antenna with three different dielectric loadings are also measured at 8.985 and 10.0 GHz. The work presented here can provide useful design guidelines for development of optimum dielectric‐loaded helical antenna, which may find potential application in satellite communication. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1195–1203, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24286
Compact asymmetric coplanar strip‐fed antenna for wideband applications
Authors: Laila D. , Deepu V. , Sujith R. , Aanandan C. K. , Vasudevan K. , Mohanan P.
Published: March 2009

An asymmetric coplanar strip‐fed uniplanar antenna for wideband applications is presented. The resulting antenna offers a 2:1 VSWR bandwidth greater than 100% from 1.58 to 5.48 GHz covering the DCS/PCS/IEEE 802.11a/WiMAX bands. The antenna has an overall dimension of 44 × 35 mm2 when printed on a substrate of dielectric constant 4.4 and height 1.6 mm. The design equation is also presented in this article. The antenna exhibits good radiation characteristics and moderate gain in the entire operating band. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1170–1172, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24287
On the inapplicability of a negative‐phase‐velocity condition as a negative‐refraction condition for active materials
Authors: Lakhtakia Akhlesh , Mackay Tom G. , Geddes Joseph B.
Published: March 2009

A negative‐phase‐velocity condition derived by Depine and Lakhtakia (Microwave Opt Technol Lett 41 (2004) 315–317) for isotropic, homogeneous, passive, dielectric‐magnetic materials is inapplicable as a negative‐refraction condition for active materials. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1230, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24289
Stacked aperture‐coupled coplanar patch antenna
Authors: Morsy Mohamed M. , Harackiewicz Frances J.
Published: March 2009

A new concept of aperture‐coupled microstrip coplanar stacked patch antenna is investigated to obtain large bandwidth, reasonable front to back ratio using new techniques to overcome regular aperture‐coupled disadvantages. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1228–1230, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24290
CPS‐fed printed pentagonal‐loop antenna with high gain and broad beam
Authors: Sun Xiao‐Meng , Yang Xue‐Xia , Wang Hua‐Hong
Published: March 2009

A CPS‐fed printed pentagonal‐loop antenna with high gain, and broad beam is proposed. This antenna has not only the high gain of 11.7 dB, but also the low cross‐polarization level less than −44 dB. Furthermore, the broad beam width with more than 60°HPBW (Half Power Beam Width) in the E plane is able to avoid the demand of precise main beam alignment. With these advantages, it can be used in the low power density applications of rectenna systems and radio frequency front‐ends. For measuring, a balun from the CPS to the microstrip line is designed. The measured results are in agreement with the simulated ones. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1188–1191, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24292
Extremely generalized planar Smith chart based on Möbius transformations
Authors: Wu Yongle , Liu Yuanan , Huang Haiyu
Published: March 2009

In this article, extremely generalized planar Smith chart (EGPSC) is proposed based on Mőbius transformations (MTs). And the rigid mathematical circles equations of this proposed EGPSC are obtained. The EGPSC includes omnipotent Smith chart (OSC) and other different kinds of generalized Smith charts which have been reported recently. Finally, according to the rigid mathematical equations, the corresponding characteristics of EGPSC are comprehensively analyzed and illustrated through numerical simulations. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1164–1167, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24293
Application of a simplified probe feed impedance formula to the design of a dual frequency patch antenna
Authors: Lu Q. , Shaikh Z. H. , Korolkiewicz E.
Published: March 2009

A simplified probe feed input impedance for a rectangular patch antenna based on the Green's function is used to design a dual frequency matched antenna. The predicted results at design frequencies of 1.9 and 2.4 GHz are in close agreement with experimental measurements. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1161–1164, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24294
Dual‐backlight unit based on a single light source integrated with a beam splitting reflector
Authors: Park Chan‐Kyu , Lee Hak‐Soon , Lee Sang‐Shin
Published: March 2009

A dual‐backlight unit incorporating a single light source integrated with a beam splitting reflector was demonstrated, providing a surface light beam for both the keypad and display section simultaneously. The reflector was realized by aligning a groove substrate with a matching cover, and a light guiding module comprising a stack of light guide panels and prism/diffuser sheets was attached to both sides of the reflector. A light emanating from the light source—placed in the middle of the substrate—undergoes a series of reflections through the reflector to reach the input of the light guiding module. Then it is transformed into a surface light beam, which is used to irradiate the keypad and display sections. As for the accomplished dual‐backlight unit, the measured average luminance and the spatial luminance uniformity were respectively about 420 cd/m2 and 70% for the keypad section, and 640 cd/m2 and 80% for the display section. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1257–1260, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24297
Uniplanar coupled‐fed printed PIFA for WWAN/WLAN operation in the mobile phone
Authors: Lee Cheng‐Tse , Wong Kin‐Lu
Published: March 2009

A coupled‐fed printed planar inverted‐F antenna (PIFA) with a compact uniplanar structure for easy implementation in the mobile phone for WWAN/WLAN operation is presented. The printed PIFA occupies a small area of 10 × 60 mm2 and provides two wide operating bands (the lower and upper bands) at about 900 and 2000 MHz for covering GSM850/900/DCS/PCS/UMTS/WLAN six‐band operation. The printed PIFA is formed by two coupled‐fed PIFAs of different sizes, a longer radiating/coupling portion and a shorter radiating/coupling portion. Owing to the use of the coupling feed, both of the two portions can generate dual‐resonance excitation, with the longer portion providing a wide lower band for GSM850/900 operation and the shorter portion providing a wide upper band for DCS/PCS/UMTS/WLAN operation. In addition, the lower and upper bands of the printed PIFA can generally be controlled separately by the longer and shorter portions, making it easy for fine tuning of the desired operating bands in practical applications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1250–1257, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24298
Analysis of optical and terahertz multilayer systems using microwave and feedback thoery
Authors: Lee Dong‐Joon , Whitaker John F.
Published: March 2009

The principles of microwave and feedback theory are independently applied to the analysis of both optical and terahertz‐regime multilayer systems. An analogy between the two approaches is drawn, and useful recursion relations, along with a signal‐flow approach, are presented for both reflection and transmission cases. These relations, in terms of S‐parameters, allow an exact analytical solution for even arbitrary, active, stratified structures, not only for any wavelength in the radio‐frequency spectrum, but also for optical wavelengths. This approach also provides a bridge between the microwave and optical bands and leads to beneficial design solutions for intermediate bands such as the THz regime. Comparisons with conventional methodologies are provided using practical multilayer simulations. In addition, graphical design techniques from microwave theory are used along with examples for efficient design and understanding. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1308–1312, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24301
Numerical analysis of electrically small structures embedded in a layered medium
Authors: Chen Yongpin P. , Xiong Jie L. , Chew Weng Cho , Nie Zaiping P.
Published: March 2009

Accurate numerical analysis of electrically small structures embedded in a layered medium is presented in this letter. In our approach, the matrix‐friendly layered medium Green's function is implemented for its elegant expression and singularity of lowest order. The current is decomposed into divergence‐free part and nondivergence‐free part according to quasi‐Helmholtz decomposition when frequency tends to zero, to capture both capacitance and inductance physics. Frequency normalization is applied after analyzing frequency scaling properties of different blocks of the matrix system. Similar to the free space case, connection matrix is utilized to make the electro‐quasi‐static block amenable to iterative solvers. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1304–1308, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24302
Microwave properties of arrowroot and its medical applications
Authors: Kalappura Ullas G. , Augustine Robin , Mathew K. T.
Published: March 2009

Arrowroot (Maranta arundinacea) is an edible starch, commercially available as powder, prepared from the roots of the plant family Marantaceae. Arrowroot is well known for its medicinal effects and use as chief ingredient in infant cookies. Arrowroot in film form is prepared and its microwave absorption characteristics, permittivity, loss factor, conductivity, skin depth, and heating coefficient are analyzed. The results are quite promising and can be concluded that arrowroot in film form is a potential candidate for several applications in medical field, when compared with well studied chitosan film. © 2009 Wiley Pe riodicals, Inc. Microwave Opt Technol Lett 51: 1267–1270, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24304
Computer‐aided modeling of circular conductors
Authors: Musa Sarhan M. , Sadiku Matthew N. O.
Published: March 2009

Circular conductors have manufacturing advantage compared with rectangular conductors in building microwave components such as filters and couplers which make it very popular for microwave designers. The accurate and efficient evaluation results of the capacitance, inductance, and characteristic impedance of circular conductors can help the designers to optimize the layout of the integrated circuits. In this article, we use the finite element method to compute the capacitance per unit length, inductance per unit length, and characteristic impedance of circular conductors. Mainly, we focus our computation and modeling on four types of systems as follows: a single circular wire above ground plane in a dielectric layer, a single circular conductor above a ground plane in a lossy dielectric layer, parallel coupled slab lines with homogenous dielectric layer, and three circular rod arrays in a rectangular trough with homogenous dielectric layer. Comparisons with published results demonstrate excellent agreement with the modeling. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1366–1372, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24307
Cascaded dual‐mode square‐loop resonators using Hilbert‐curve perturbation for wide bandpass filter applications
Authors: Liu Ji‐Chyun , Li Chiung‐Hung , Kuei Ching‐Pin , Zeng Bing‐Hao
Published: March 2009

The cascaded dual‐mode square‐loop resonator (DMSLR) with Hilbert‐curve perturbation is introduced to design wide band‐pass filter in this article. To obtain low insertion loss (−0.85 dB), high out‐of‐band rejection level (−51.82 dB), and wider band (BW 62.3%) responses, using Hilbert‐curve perturbation and cascaded technique are proposed here. The equivalent circuit and Chebyshev response are presented for approximation and analysis. Results including surface current distributions and frequency responses are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1294–1298, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24311
Microwave photonic bandpass filter using a multi‐wavelength laser with a bell‐shaped power profile
Authors: Zhou J. Q. , Aditya S. , Shum P. , Cheng L. H. , Parhusip B. P. , Wong Vincent , Lim Desmond
Published: March 2009

A low cost sidelobe suppressed tunable microwave photonic bandpass filter is proposed and experimentally demonstrated. The filter is based on a multi‐wavelength ring laser and a segment of single mode fiber as a dispersive element. Through adjustment of the power profile of the multi‐wavelength laser to a bell shape, a filter frequency response without sidelobes is achieved. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1329–1332, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24316
A fully integrated single core VCO with a wide tuning range for DVB‐H
Authors: Lalchand Khemchandani Sunil , del Pino Suarez Javier , Diaz Ortega Roberto , Hernandez Antonio
Published: March 2009

This article presents a fully integrated LC VCO in a low cost 0.35 μm BiCMOS technology for DVB‐H standard. The VCO was designed for a direct conversion receiver architecture. To facilitate the integration of inductors and capacitors, the circuit oscillates at twice the required UHF frequency. Techniques like emitter degeneration, capacitor divider, and optimum bias and tank design have been used to improve phase noise requirements. The obtained phase noise is −112 dBc/Hz at 100 kHz offset and the tuning range is 47.6%. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1338–1343, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24318
Novel triangular‐type electromagnetic bandgap structure for ultra‐broadband suppression of simultaneous switching noise
Authors: Kwon Jong‐Hwa , Sim Dong‐Uk , Kwak Sang‐Il , Gwan Yook Jong
Published: March 2009

To build a stable power distribution network for high‐speed digital systems, simultaneous switching noise (SSN) in multilayer PCBs and packages needs to be sufficiently suppressed. In this article, a novel triangular‐type uniplanar compact electromagnetic band‐gap with different bridges designed for power/ground planes is proposed for the ultra‐broadband suppression of SSN. The SSN suppression performance of the proposed structure is validated both numerically and experimentally. A −30 dB suppression bandwidth for SSN is achieved starting at 800 MHz and extending to 15 GHz and beyond, that is, almost the entire noise band. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1356–1358, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24322
Ultra‐lightweight dual‐polarized X‐band array antenna for airborne weather radar applications
Authors: Ren Yu‐Jiun , Zhang Yan
Published: March 2009

A dual‐polarized X‐band array antenna for advanced airborne weather hazard monitoring radar applications is presented. This low‐profile array is composed of 8 × 8 circular patch antenna elements with a hybrid feed‐line network providing dual‐polarization function and high isolation (∼40 dB) between H‐ and V‐ports. The antenna operation bandwidth is from 9.9 to 10 GHz, and has a radiation gain of 19 dBi and cross‐polarization of 31 dB. The array can be easily placed on the aircraft fuselage because of its ultra‐thin thickness (0.13 mm), ultra‐lightweight, and conformal structure, and it has potential applications in radar surveillance, remote sensing, and wireless communications. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1324–1326, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24323
Closed‐form design method for unequal lumped‐elements Wilkinson power dividers
Authors: Wu Yongle , Liu Yuanan
Published: March 2009

The unequal Wilkinson power dividers using flexible and miniaturized lumped‐elements are proposed in this article. First, two kinds of lumped‐elements structures including Pi‐network and T‐network are developed as the transformers between two different resistances. Then the closed‐form design method for the proposed power dividers based on these transformers is presented. Furthermore, the frequency characteristics of some examples are simulated according to the calculated results got by the closed‐from design method. Finally, three types of circuit layouts are fabricated to realize the lumped‐element unequal Wilkinson power dividers flexibly. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1320–1324, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24324
Characterization and lumped circuit model of ultra‐wideband flip‐chip transitions (DC 110 GHz) for WAFER‐scale packaging
Authors: Seek Cho Young , Franklin Drayton Rhonda
Published: March 2009

An ultra‐wideband flip‐chip transition is proposed for wafer level packaging applications. The locally matched flip‐chip scheme has an air cavity underneath a flip‐chip die and local trenches in the flip‐chip bond pad area to provide matching. The measured response up to 110 GHz has a return loss below 20 dB across 96% of the band and has an insertion loss improvement of 2.2 dB at 110 GHz. The design approach is simple and requires no additional space. Also presented is lumped element circuit model for the transition region of conventional and locally matched flip‐chip interconnect. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1281–1285, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24326
A planar hybrid antenna for UWB application
Authors: Chen Wen‐Shan , Lin Chi‐Huang
Published: March 2009

A novel hybrid antenna formed by a printed monopole slot (open‐ended slot) and a printed monopole for Ultra‐Wideband (UWB) operation is presented. The monopole slot and monopole are fed in series using a 50 Ω microstrip feed line and printed on a FR4 substrate of small size 30 × 34 mm2. The monopole is on the top edge of the proposed antenna and can provide a wide impedance bandwidth for UWB upper band operation (6.15 GHz–10.6 GHz). The monopole slot is printed below the monopole and is used to excite a quarter‐wavelength resonant mode at about 4 GHz for UWB lower band operation (3.1 GHz–4.8 GHz). Detailed results and parametric studies of the proposed hybrid antenna are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1243–1246, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24328
Design of a compact dual‐mode patch resonator band‐pass filter
Authors: Li Jia‐Lin , Qu Shi‐Wei , Xue Quan
Published: March 2009

In this article, a compact dual‐mode patch resonator for band‐pass filter applications is developed. The size reduction of the studied filter is simply achieved by etching a dual‐cross slot on the patch. Studies indicate that with this arrangement, the size can be reduced to 26.7% as compared to the conventional patch resonator. Meanwhile, a pair of transmission zeros close to the pass band improves its selectivity. A demonstrator filter is optimally designed, fabricated and measured. Both measurements and simulations are presented and compared in the article. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1382–1385, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24329
A “thru‐short” method for noise de‐embedding of MOSFETs
Authors: Nan Lan , Xiong Yong‐Zhong , Mouthaan Koen , Issaoun Ammar , Shi Jinglin , Ooi Ban‐Leong
Published: March 2009

A “thru‐short” noise de‐embedding method for MOSFETs is presented. The capability of the “thru‐short” method has been validated through a comparison of measured and de‐embedded noise parameters using different methods. It is shown that the “thru‐short” method is reliable for on‐wafer de‐embedding of both S‐parameters and noise parameters up to 18 GHz. Noise contributions from the parasitics due to the contact pads and interconnections surrounding the MOSFET can be determined and removed accurately. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1379–1382, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24330
Improved phase noise for dielectric resonators oscillators with broadband tuning
Authors: Zhou Liang , Wu Zhuo
Published: March 2009

In this article, we describe a method of design of very low phase noise dielectric resonators oscillators at 13 GHz. By using two Silicon Germanium transistors with total gains 8 dB and lower flicker noise corner between 10 kHz and 40 kHz, the phase noise of the oscillators can be achieved −125 dBc/Hz at 10 kHz offset. The resonator has unloaded Q around 14,000 at operating frequency and is then optimized and coupled to the amplifiers for minimum phase noise whereQL/Q0= 1/2 henceS21= −6 dB. To incorporate tuning, phase shifter is also investigated. The phase noise measurement system is also presented using two identical oscillators phase locked at the same frequency.© 2009 Wiley Pe riodicals, Inc. Microwave Opt Technol Lett 51: 1312–1316, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24334
Novel approach to the design of unequal power divider with high‐dividing ratio
Authors: Yang Tan , Chen Jian‐Xin , Xue Quan
Published: March 2009

This letter presents the design of an unequal Wilkinson power divider with a high‐dividing ratio. By proportionally reducing the impedances in both arms and employing T‐shaped structure to replace quarter wavelength transmission lines with very low characteristic impedances, the proposed circuit can be constructed by microstrip lines with reasonable characteristic impedances, and therefore is easy to be fabricated and has planar structure. Furthermore, the value of isolating resistor can be flexibly adjusted to an available one. To verify our proposed idea, a 4:1 microstrip unequal power divider operating at 1.9 GHz is fabricated and tested. The ratio of highest to lowest characteristic impedances is only 2.2:1 in this 4:1 unequal power divider, compared with the ratio of 4.5:1 in conventional divider. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 1240–1243, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24337
Effects of simvastatin, acetylsalicylic acid, and rosiglitazone on proliferation of normal and cancerous prostate epithelial Cells at therapeutic concentrations
Authors: Murtola Teemu J. , Pennanen Pasi , Syvälä Heimo , Bläuer Merja , Ylikomi Timo , Tammela Teuvo L.J.
Published: March 2009

BACKGROUND

Non‐steroidal anti‐inflammatory drugs and cholesterol‐lowering statins have been reported to inhibit prostate cancer cell growth suggesting their chemopreventive potential within the prostate. However, the effect has been demonstrated only with advanced prostate cancer cell lines and with drug concentrations above the clinical therapeutic range. In this study we compared the effect of therapeutic concentrations of acetylsalicylic acid, simvastatin and rosiglitazone on the growth of a set of prostatic primary cultures and various prostate epithelial cell lines.

METHODS

Two primary epithelial cell lines isolated from surgical resecates of normal prostate tissue (P96E, P97E), a primary cell line isolated from untreated prostate carcinoma (ESTO1), two transformed prostate epithelial cell lines (PWR1‐E, RWPE‐1) and advanced cancer cell lines LNCaP and VCaP were used in the study. Cells were treated for seven days with therapeutic concentrations of acetylsalisylic acid, simvastatin, rosiglitazone or their combination. Cellular growth rate was measured by crystal violet staining method.

RESULTS

Acetylsalicylic acid (0.5 mM) and simvastatin (10 nM) inhibited the growth of prostate epithelial cells of normal and primary cancer origin, whereas advanced cancer cell lines were resistant to the effect. Rosiglitazone at the therapeutic level of 1 µM did not reduce the growth of any cell type studied.

CONCLUSIONS

Our results demonstrate that acetylsalicylic acid and simvastatin inhibit prostate epithelial cell growth at clinically relevant doses. This should be acknowledged when designing possible prostate cancer chemopreventive trials. Prostate 69: 1017–1023, 2009. © 2009 Wiley‐Liss, Inc.
Prediction of protein‐glucose binding sites using support vector machines
Authors: Nassif Houssam , Al‐Ali Hassan , Khuri Sawsan , Keirouz Walid
Published: March 2009

Glucose is a simple sugar that plays an essential role in many basic metabolic and signaling pathways. Many proteins have binding sites that are highly specific to glucose. The exponential increase of genomic data has revealed the identity of many proteins that seem to be central to biological processes, but whose exact functions are unknown. Many of these proteins seem to be associated with disease processes. Being able to predict glucose‐specific binding sites in these proteins will greatly enhance our ability to annotate protein function and may significantly contribute to drug design. We hereby present the first glucose‐binding site classifier algorithm. We consider the sugar‐binding pocket as a spherical spatio‐chemical environment and represent it as a vector of geometric and chemical features. We then perform Random Forests feature selection to identify key features and analyze them using support vector machines classification. Our work shows that glucose binding sites can be modeled effectively using a limited number of basic chemical and residue features. Using a leave‐one‐out cross‐validation method, our classifier achieves a 8.11% error, a 89.66% sensitivity and a 93.33% specificity over our dataset. From a biochemical perspective, our results support the relevance of ordered water molecules and ions in determining glucose specificity. They also reveal the importance of carboxylate residues in glucose binding and the high concentration of negatively charged atoms in direct contact with the bound glucose molecule. Proteins 2009. © 2009 Wiley‐Liss, Inc.
Antibacterial activity of sophoraflavanone G Isolated from the roots of Sophora flavescens against methicillin‐resistant Staphylococcus aureus
Authors: Cha Jeong‐Dan , Moon Sang‐Eun , Kim Ji‐Young , Jung Eun‐Kyung , Lee Young‐Soo
Published: March 2009

In this study, sophoraflavanone G obtained from Sophora flavescens was evaluated against 10 clinical isolates of methicillin‐resistant Staphylococcus aureus (MRSA), either alone or in combination with ampicillin or oxacillin, via checkerboard assay. At the end point of an optically clear well, the minimum inhibitory concentrations (MICs) ranged from 0.5 to 8 µg/ml for sophoraflavanone G, from 64 to 1024 µg/ml for ampicillin, and from 256 to 1024 µg/ml for oxacillin. The combination of sophoraflavanone G and ampicillin or oxacillin yielded a fractional inhibitory concentration index ranging from 0.188 to 0.375, thereby indicating a principally synergistic effect. The synergistic interaction was verified by time‐kill studies using sophoraflavanone G and/or antibiotics. Thirty minutes of treatment with sophoraflavanone G with ampicillin or oxacillin resulted in an increase in the rate of killing in units of CFU/ml to a greater degree than was observed with Sophoraflavanone G alone. These findings indicated that the application of the tested sophoraflavanone G alone or in combination with antibiotics might prove useful in the control and treatment of MRSA infections. Copyright © 2009 John Wiley & Sons, Ltd.
Genistein and curcumin suppress epidermal growth factor‐induced MUC5AC mucin production and gene expression from human airway epithelial cells
Authors: Heo Ho Jin , Lee Su Yel , Lee Mi Nam , Lee Hyun Jae , Seok Jeong Ho , Lee Choong Jae
Published: March 2009

This study investigated whether genistein and curcumin affect epidermal growth factor (EGF)‐induced MUC5AC mucin production and gene expression from human airway epithelial cells. Confluent NCI‐H292 cells were pretreated with each agent for 30 min and then stimulated with EGF for 24 h. The MUC5AC mucin gene expression and mucin protein production were measured by reverse transcription – polymerase chain reaction (RT‐PCR) and enzyme‐linked immunosorbent assay (ELISA), respectively. The results were as follows: (1) genistein and curcumin inhibited the production of MUC5AC mucin protein induced by EGF, dose‐dependently; (2) genistein and curcumin also inhibited the expression of MUC5AC mucin gene induced by EGF. This result suggests that genistein and curcumin can regulate mucin gene expression and production of mucin protein induced by EGF, by directly acting on airway epithelial cells. Copyright © 2009 John Wiley & Sons, Ltd.
Cytogenetic investigation of chromosomal aberrations in cells treated with plantamajoside from Plantago asiatica
Authors: Koo Yun‐Chang , Jung Sung‐Hoon , Yang Ji‐Hee , Ryu Yung‐sun , Kim Eun‐jin , Lee Kwang‐Won
Published: March 2009

Plantago asiatica is a member of the Plantaginaceae family, and is widely distributed in East Asia. In our previous work, a single active compound, plantamajoside was isolated and confirmed to have glycation inhibitory activity, and did not possess toxicity during a 90 day repeated oral toxicity test in rats. In the present study, a chromosomal aberration test was performed to investigate the genotoxicity of plantamajoside. From the results of the cytotoxicity test, plantamajoside proved to be less toxic when it was treated combined with S9 cell fractions. However, there was a significant increase in structural aberrations during the short‐term treatment of plantamajoside at its highest dose (5000 µg/mL) even when combined with S9. This seems to have been a natural phenomenon due to the very high dose of plantamajoside that was used. However, to confirm the safety of plantamajoside for its potential use as a phytochemical agent in health products, additional mutagenicity tests are necessary. Copyright © 2009 John Wiley & Sons, Ltd.
Amelioration of adjuvant induced arthritis by apocynin
Authors: Pandey Anjali , Kour Kiranjeet , Bani Sarang , Suri Krishna Avtar , Satti Naresh Kumar , Sharma Punita , Qazi Ghulam Nabi
Published: March 2009

The premise of the study was to investigate the antiarthritic potential of apocynin (APO) in Balb/c mice (in vivo). The experiment showed a dose‐dependent decrease in oedema and showed a suppression of proinflammatory cytokines such as TNF‐α and IL‐1β and mediators such as prostaglandin E2 (PGE2) and LTB4. At oral doses of 0.5, 1.0, 2.0 and 4.0 mg/kg once daily during the course of the experiment, APO induced an inhibition of T cell mediated immune response causing suppression of CD4+ and CD8+ T cells and of intracellular interferon‐gamma (IFN‐γ) by flow cytometry in arthritic mice. In parallel there was a dose‐dependent inhibition in vascular permeability causing an inhibition in the migration of leucocytes and exudate volume at the site of the inflammatory reaction. These observations validate the immunoregulatory potential of apocynin. Copyright © 2009 John Wiley & Sons, Ltd.
Comparative clinical trial of castor oil and diclofenac sodium in patients with osteoarthritis
Authors: Medhi B. , Kishore K. , Singh U. , Seth S. D.
Published: March 2009

A randomized, double‐blind, comparative clinical study was conducted to compare the safety and efficacy of castor oil with diclofenac sodium in patients with knee osteoarthritis. Subjects with symptoms of knee osteoarthritis were given a castor oil capsule 0.9 mL (n= 50) thrice daily for 4 weeks or a capsule of diclofenac sodium (n= 50), 50 mg thrice daily for 4 weeks. The subjects completed an overall evaluation of symptom relief at 2 weeks and 4 weeks of completed treatment. The subjects were evaluated by clinical, routine laboratory and radiographic investigations for improvement of disease conditions and also for adverse drug reaction. On completion of 4 weeks treatment it was observed that both drugs were significantly effective in the treatment of knee osteoarthritis (p< 0.001) and adverse drug reactions were high with diclofenac sodium, whereas with castor oil there were no adverse effects reported. The present study indicates that castor oil can be used as an effective therapy in primary knee osteoarthritis. Copyright © 2009 John Wiley & Sons, Ltd.
Influence of rainfall and beaver dams on upstream movement of spawning Atlantic salmon in a restored brook in Nova scotia, Canada
Authors: Taylor Barry R. , MacInnis Charles , Floyd Trevor A.
Published: March 2009

In a restored, third‐order stream in northern Nova Scotia, Canada, we used redd counts over 12 years to examine the influence of beaver dams and the timing and intensity of autumn rains on spawning activity of Atlantic salmon. Most beaver dams in most years had no detectable effect on the distribution of spawning redds, but in 2004 the density of redds downstream from a three‐dam complex was significantly greater than that above, suggesting the dams were a barrier to many fish. A second complex of dams blocked salmon passage completely in 2003 and 2004 until they were notched to provide access upstream. The length of stream used by salmon for spawning was linearly correlated with total precipitation in the basin in October plus November (R2 = 0.60), to a ceiling of 325 mm, above which the fish had access to the entire brook, if beaver dams were notched. Number of redds in the whole brook was strongly correlated (R2 = 0.94) with the coefficient of variation (CV) of daily rainfall in October, but only for 7 of 11 years. This relationship disappeared when the impassable beaver dam complex failed in 2005, allowing salmon free access to 4 km of the upper brook. Variation in rainfall, and hence discharge, in this flashy brook evidently influences migration and spawning of Atlantic salmon in conjunction with channel blocking by beaver dams. Copyright © 2009 John Wiley & Sons, Ltd.
Decay state and inundation history control assemblage structure of log‐dwelling invertebrates in floodplain forests
Authors: Ballinger Andrea , Nally Ralph Mac , Lake P. Sam
Published: March 2009

Fallen timber (logs, large boughs) is recognized as having high ecological significance on forest floors. In floodplain forests, fallen timber potentially has even higher value for supporting biodiversity than upland forests because distinct faunal elements use the timber in the flooded and unflooded conditions. Invertebrates were sampled in logs of the river red gum (Eucalyptus camaldulensis Dehnh.) that had been inundated 1 year earlier and compared with invertebrates in logs that had not been inundated for many years. The invertebrate fauna in river red gum logs was relatively depauperate, probably reflecting the variable, sub‐humid conditions on the floodplain. The abundance and taxon richness of invertebrates was highest in logs with greater structural complexity and heterogeneity due to extensive decay. Recent inundation slightly reduced taxon richness. The succession of log‐dwelling invertebrates was tracked though transitions between terrestrial fauna and aquatic fauna in a spring/summer flood cycle. Transition between the two faunae was rapid. Logs were colonized by aquatic invertebrates within 2 weeks of immersion by floodwaters and recolonized by terrestrial invertebrates within 4 weeks of emersion. This faunal dynamism highlights the need to consider the entire flood cycle in decisions about the management of fallen timber on floodplains for biodiversity. Copyright © 2009 John Wiley & Sons, Ltd.