bluuebunny/crossref_metadata_2025 huggingface dataset:
Fresnel coefficients for a permittivity‐permeability phase space encompassing vacuum, anti‐vacuum, and nihility
Authors: Lakhtakia Akhlesh , Mackay Tom G.
Published: December 2005

The concept of the electromagnetic trinity comprising vacuum, anti‐vacuum, and nihility is extended to a zone in the 4‐D εr‐μr phase space that was largely inaccessible until the recent emergence of negative‐phase‐velocity materials. Expressions for Fresnel coefficients are derived for the reflection of plane waves at the planar interface of vacuum and a homogeneous, isotropic, dielectric‐magnetic medium with constitutive properties lying in that zone. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 265–270, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21323
Compact 2D Hilbert microstrip resonators
Authors: Crnojević‐Bengin Vesna
Published: December 2005

Novel compact microstrip resonators consisting of multiple 2D Hilbert prefractal curves are presented. Proposed resonators use fractal curves of the 3rd and 4th orders to achieve length reduction of over 64% and 81%, respectively, when compared to the conventional capacitively coupled resonators tuned to the same frequency. A configuration with fractal curves of the 3rd order, fabricated in standard PCB technology, exhibits improvement of unloaded Q‐factor within range from 15% to 90%, depending on the resonant frequency. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 270–273, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21324
1.55‐μm DFB lasers over a wide temperature range for analog application
Authors: Koo Bon‐Jo , Song Han‐Wook , Kim Yong‐Kwan , Park Chil‐Sung , Ryu Han‐Gwon , Huh Kwang‐Soo , Park Seung‐Bae , Lhee Zail , Choe Hyosin , Lee Seok , Han Sang‐Kook
Published: December 2005

Strained‐layer multiquantum‐well distributed‐feedback (SL‐MQW‐DFB) lasers at a wavelength of 1.55 μm operating from −40°C to 85°C without any coolers are demonstrated. The average value of IMD3 at 1.8 GHz and 5 mW operating conditions was −71 dBc, and the RIN at 2 mW was measured as 151 dB/Hz. The uncooled DFB lasers we have developed are very useful for mobile applications. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 273–275, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21325
Permittivity measurement of low and high loss liquids in the frequency range of 8 to 40 GHz using waveguide transmission line technique
Authors: Afsar Mohammed N. , Suwanvisan Nattakarn , Wang Yong
Published: December 2005

This paper presents the complex permittivity of a number of liquids measured using waveguide transmission‐line techniques. These liquids are measured over four frequency ranges: 8–12.4 GHz, 12.4–18 GHz, 18–26.5 GHz, and 26.5–40 GHz (or at the X, Ku, K, and Ka bands). The measured results of liquids are discussed and compared with results in the literature and the calculated data using Debye's method. Finally, statistical values such as the means and standard deviations, and the percentages of permittivity errors are computed for the consideration of data spread and error estimation. All of the possible sources of errors are also discussed with regard to improvements and developments of measurements in the near future. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 275–281, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21326
A novel compact bandpass filter using microstrip defected ground structure
Authors: Shi Jin , Li JiaLin
Published: December 2005

A novel compact microstrip bandpass filter using a dumbbell‐shaped defected ground structure (DGS) etched in ground plane under microstrip line is proposed. The bandpass characteristic is easy to obtain by adjusting the bandgaps of the DGS resonators. The filter has the advantages of compact size, high selectivity, and high out‐of‐band suppression due to the transmission zeros. The theoretical and experimental results of the proposed bandpass filter are presented and show good agreement. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 281–283, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21327
Suppression of spurious radiations of patch antennas using split‐ring resonators (SRRs)
Authors: Lee Jae‐Gon , Lee Jeong‐Hae
Published: December 2005

The spurious radiation of patch antennas is suppressed by the band‐stop characteristic of split‐ring resonators (SRRs). The SRRs are located near the feed line of the upper substrate so as to couple the perpendicular magnetic field to the SRRs. The SRRs can be characterized with negative permeability and positive permittivity around the resonance frequency and, thus, waves cannot propagate. To eliminate the first and second spurious radiations, the design equations of a band‐stop filter using SRRs are suggested. The reflection coefficient and the far‐field radiation pattern of a patch antenna with SRRs are obtained via full‐wave simulation and measurement. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 283–287, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21328
A wideband array antenna with beam‐steering capability using real valued weights
Authors: Bialkowski Marek E. , Uthansakul Monthippa
Published: December 2005

This article presents an array antenna with beam‐steering capability in azimuth over a wide frequency band using real‐valued weighting coefficients that can be realized in practice by amplifiers or attenuators. The described beamforming scheme relies on a 2D (instead of 1D) array structure in order to make sure that there are enough degrees of freedom to realize a given radiation pattern in both the angular and frequency domains. In the presented approach, weights are determined using an inverse discrete Fourier transform (IDFT) technique by neglecting the mutual coupling between array elements. Because of the presence of mutual coupling, the actual array produces a radiation pattern with increased side‐lobe levels. In order to counter this effect, the design aims to realize the initial radiation pattern with a lower side‐lobe level. This strategy is demonstrated in the design example of 4 × 4 element array. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 287–291, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21329
Phase‐mode‐based construction of a coupling matrix for uniform circular arrays with a center element
Authors: Rogier Hendrik
Published: December 2005

A rigorous circuit model with a limited number of parameters is presented to describe mutual coupling in uniform circular arrays (UCAs) with a center element. The model, which is based on a phase‐mode expansion, is applied to construct a coupling matrix in order to compensate for mutual coupling in this type of arrays. A sample dual‐band uniform circular array with center element illustrates the use of the coupling matrix for direction‐of‐arrival (DOA) estimation. It is explained in which cases mutual coupling is fully taken into account by the coupling matrix and in which cases some residual errors due to mutual coupling remain in the DOA. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 291–298, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21330
Full‐wave analysis of single and coupled striplines in multilayered cylindrical dielectrics using the 3D TLM method
Authors: Gupta Alok Kumar , Mohan Akhilesh , Biswas Animesh
Published: December 2005

In this paper, an inhomogeneous, multilayered cylindrical stripline is analyzed using the 3D‐TLM method. Dispersion characteristics of dominant as well as higher‐order modes are obtained for single and coupled cylindrical striplines. Impedance characteristics for the dominant mode are also obtained for the same. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 298–302, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21331
Performance of integrated antennas on silicon substrates of high and low resistivities up to 110 GHz for wireless interconnects
Authors: Zhang Y. P. , Sun M. , Fan W.
Published: December 2005

Monopoles of 1‐mm axial length are designed and fabricated on silicon substrates of high‐resistivity 5 kΩ‐cm and low‐resistivity 10 Ω‐cm, respectively. We measure their performance up to 110 GHz for wireless interconnects for the first time. The reflection measurements show that a sharp resonance can be seen at 75 GHz for the meander monopole and monopole pairs at 67 and 104 GHz for the zigzag 30° monopole on the silicon substrate of high resistivity, but no such sharp resonance can be seen for those on the silicon substrate of low resistivity. Transmission measurements show that a high‐gain window exists. The existence of the high‐gain window is the most important finding of this work and is useful in the design of chip‐scale radios or wireless chip area networks. This suggests that the operating frequency of wireless interconnects be allocated within the high‐gain window for good performance. Furthermore, metal lines running parallel with or vertical to the monopole pairs are observed to improve the highest gain of this window area. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 302–305, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21332
Noise reduction using photonic microwave filter for radio over fiber system
Authors: Lu Jinyue , Chi Hao , Zhang Xianmin , Shen Linfang
Published: December 2005

A photonic microwave filter based on fiber loop and fiber Bragg gratings (FBGs) is applied in a radio‐over‐fiber (RoF) system to suppress the relative intensity noise (RIN) of laser and the amplified spontaneous emission (ASE) noise of erbium‐doped fiber amplified (EDFA). The experiment results show that the signal‐to‐noise ratio (SNR) of the system can be effectively improved by using such a noise filter in the system. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 305–307, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21333
A novel tulip‐shaped monopole antenna for UWB applications
Authors: Chang Dau‐Chyrh , Liu Ji‐Chyun , Liu Ming‐Yen
Published: December 2005

A novel planar monopole antenna designed with tulip‐shaped structure is proposed for UWB applications. The corolla of tulip‐shaped structure is constructed with petal and calyx by the EM‐mode synthesis. By tuning the petal structure, wideband performance covering 2.55 to 40.5 GHz (1:16) with −10‐dB return loss is measured. The radiation patterns are omnidirectional patterns. Antenna gain is 0.2 to 4.0 dBi in the operating range. The current distributions are simulated for demonstration. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 307–312, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21334
Implementation of a low‐cost phase‐locked loop clock‐recovery module for 40‐Gb/s optical receivers
Authors: Woo Dong Sik , Kim Kang Wook , Lim Sang‐Kyu , Ko Jesoo
Published: December 2005

A low‐cost, compact, high‐performance clock‐recovery (CR) module using a new phase‐locked loop (PLL) for 40‐Gb/s optical receivers is successfully designed and implemented. The newly implemented frequency detector in the PLL helps to reduce the current consumption and also extended the frequency‐capture range. The implemented PLL clock‐recovery module demonstrates advantages over the conventional open‐loop type clock‐recovery module with a DR filter by significantly improving clock jitter, thus reducing overall module cost, and allowing the possibility of providing a proper clock signal in the case of temporary loss of NRZ input signals. The CR module exhibits error‐free operation during a 30‐min BER test with a time‐division‐multiplexing (TDM) 40‐Gb/s transmission system. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 312–315, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21335
Characterization of the electrical performance of different signal via geometries
Authors: Agili Sedig S. , Smith Stephen B. , Balasubramanian Vittal
Published: December 2005

Several signal via geometries are analyzed for across and through transmission by varying the drill‐hole diameter, ratio of the pad and antipad diameters to drill‐hole diameter, and number of ground planes. Time‐ and frequency‐domain results showing impedance‐, insertion‐, and return‐loss trends, which are useful for designing via geometries for high‐speed transmission, are obtained. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 315–320, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21336
Direct optical‐to‐microwave domain conversion
Authors: Haridim M. , Hachamo Y. Z. , Lembrikov B. I. , Mechani O. , Ben‐Ezra Y. , Podevin F.
Published: December 2005

A novel method for direct conversion of optical signals into microwave signals is proposed. This method is based on the optical controlling of microwave devices. The feasibility of the proposed method is experimentally proved for a microstrip line implemented on Si substrate. We present experimental results for conversion of on‐off keying (OOK) optical signals to binary amplitude‐shift keying (ASK) microwave signals. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 320–322, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21337
Multiscaling reconstruction of metallic targets from TE and TM experimental data
Authors: Azaro R. , Donelli M. , Franceschini D. , Massa A.
Published: December 2005

The noninvasive imaging of unknown objects is of particular interest in several industrial applications. In this paper an iterative multiresolution strategy (IMRS) is applied to the reconstruction of metallic targets from experimental measurements. A representative test case is presented for evaluating the effectiveness of the IMRS for dealing with real data collected in a controlled environment in both TE and TM illuminations. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 322–324, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21338
A compact printed hook‐shaped monopole antenna for 2.4/5‐GHz wlan applications
Authors: Lee Chi‐Hun , Park Seong‐Ook
Published: December 2005

This paper proposes a compact printed hook‐shaped monopole antenna for 2.4/5‐GHz WLAN applications. The designed antenna has a compact size with dimensions 26 × 10 × 1 mm3. The impedance bandwidth (VSWR < 2) of the proposed antenna is about 170 MHz (2.32–2.49 GHz) for 2.4‐GHz (Bluetooth) bands and 4500 MHz (4.4–8.9 GHz) for the 5‐GHz (WLAN) bands. The radiation patterns are nearly omnidirectional, which is similar to typical those of monopole antenna. The maximum measured radiation gains are 1.45 dBi at 2.43 GHz and 3.37 dBi at 5.8 GHz, respectively. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 327–329, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21340
Artificial magnetic conductor using split ring resonators and its applications to antennas
Authors: Oh Soon‐Soo , Shafai Lotfollah
Published: December 2005

An artificial magnetic conductor using the split‐ring resonators (SRRs) printed on conductor‐backed dielectric substrate is presented. The simulation and measurement verify that the magnetic conductor is successfully accomplished around the resonant frequency. As an antenna application, the characteristics of a horizontal wire antenna placed above the SRR array, as well as a conducting ground plane and a grounded dielectric slab, are investigated and compared. A maximum gain of 4.34 dBi is obtained for the wire antenna above the SRR array. The results confirm that the split resonators can successfully be used to replace the antenna ground plane in order to improve their performance. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 329–334, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21341
Polarization‐insensitive polymer waveguide Bragg gratings
Authors: Cheng S. Y. , Chiang K. S. , Chan H. P.
Published: December 2005

We report the design and fabrication of Bragg gratings in benzocyclobutene (BCB) channel waveguides with emphasis on the demonstration of their polarization dependence. The effects of the stress‐induced birefringence in the waveguide on the polarization dependence of the Bragg gratings are characterized and discussed. Our results show the possibility of realizing tunable polarization‐insensitive Bragg‐grating filters with simple polymer waveguide structures. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 334–338, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21342
A 176‐190 GHz transmitter module using indium phosphide and gallium arsenide MMICs
Authors: Archer John W. , Shen Mei Gan
Published: December 2005

This paper describes a double‐sideband, upconverting transmitter module with a potential application to future‐generation point‐to‐point telecommunications in the 176–190‐GHz band. The multichip module incorporates indium phosphide (InP) and gallium arsenide (GaAs) monolithic microwave integrated circuits (MMICs). It is believed that this is the first time an all‐MMIC transmitter module has been reported in this frequency band. The small‐signal up‐conversion gain falls approximately monotonically from 0 dB for output at 176 GHz, to −15 dB for output at 190 GHz. The input frequency range covers 0.5 to 9 GHz and the local oscillator can be tuned from 45 to 47 GHz. Gain compression of 1‐dB occurs at an output power of −12 dBm at 176 GHz, decreasing to −20 dBm at 190 GHz. Output 3rd‐order intercept point is +1 dBm at 176 GHz, decreasing to −12 dBm at 190 GHz. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 338–341, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21343
X‐band microstrip Yagi array with dual‐offset aperture‐coupled feed
Authors: Venkatesan Jaikrishna
Published: December 2005

In this paper, a three‐element microstrip Yagi array is designed for operation at the X‐band. The driven patch of each microstrip Yagi element is fed using a dual‐offset aperture‐coupled feed to obtain circular polarization. Performance of the array when scanned electronically is investigated experimentally via measured field patterns. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 341–344, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21344
Advanced modulation formats for long‐haul optical‐transmission systems with dispersion compensation by chirped FBG
Authors: Yong Chen , Jihong Cao , Ting Chen , Shuisheng Jian
Published: December 2005

Nonreturn‐to‐zero (NRZ) and carrier‐suppressed return‐to‐zero (CSRZ) modulation formats transmitted in long‐haul optical‐transmission systems with different dispersion‐compensation methods are numerical evaluated. We also carry out an 8 × 10 Gb/s CSRZ‐based transmission experiment over 2560‐km standard‐fiber straight lines with dispersion compensation by chirped fiber Bragg grating (CFBG) successfully. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 344–347, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21345
Ultra‐wideband cylindrical antenna design using the Green's function method (GFM) as an absorbing boundary condition (ABC) and the radiated field propagator in a genetic optimization
Authors: Holtzman R. , Kastner R. , Heyman E. , Ziolkowski R. W.
Published: December 2005

An ultra‐wideband antenna is designed using genetic optimization and the finite‐difference‐time‐domain (FDTD) method. Efficiency is enhanced by using the Green's function method (GFM) as an absorbing boundary condition (ABC) close to the antenna surface, and as a propagator to the radiated field at any observation point at each iteration step. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 348–354, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21346
Scattering from an annular slot on a radial waveguide
Authors: Kim Jae H. , Eom Hyo J.
Published: December 2005

The boundary‐value problem of scattering from an annular slot on a radial waveguide is solved. The scattered fields are expanded in terms of eigenfunctions based on the Fourier series and Hankel transform. Boundary conditions are enforced to constitute a set of simultaneous equations. A fast convergent series solution is obtained using residue calculus. Computations are performed to investigate radiation and coupling by an annular slot on a radial waveguide. Favorable agreement is observed between our theory and other existing results. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:354–357, 2006; Published Online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.21347
Analytical calculation of radiated emissions from rectangular power bus using embedded capacitor in high‐speed packages and PCBs
Authors: Jeong Youchul , Kim Jaemin , Kwon Jong Hwa , Kim Joungho
Published: December 2005

We propose a method of analytical calculation of radiated emissions from a rectangular power bus using an embedded capacitor. Using this method, the radiated emissions of the test package are calculated accurately and the calculation is verified by far‐field measurement in an anechoic chamber. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:358–361, 2006; Published Online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/mop.21348
Three‐turn concave hemispherical helical antenna for satellite communication
Authors: Chen Canhui , Hu Binjie , Yung E. K. N.
Published: December 2005

A novel hemispherical helical antenna is designed for satellite communications in this paper. This antenna can produce circular polarization radiation over a wide angular coverage of 113°. The input impedance varies very stably in the range of 1 < cλ < 1.15. The 3‐dB axial‐ratio bandwidth is found to be 13.5% with relatively high gain of 9 dB. The current distribution and radiation pattern will also be presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 361–363, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21349
Uniaxial dielectric media with hyperbolic dispersion relations
Authors: Mackay Tom G. , Lakhtakia Akhlesh , Depine Ricardo A.
Published: December 2005

Planewave propagation with hyperbolic/hyperboliclike characteristics in uniaxial dielectric media is investigated. The phase velocity is positive with respect to the time‐averaged Poynting vector for both evanescent and nonevanescent propagation in nondissipative media. A conceptualization of a uniaxial medium, which exhibits hyperboliclike planewave characteristics as a homogenized composite medium, is presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 363–367, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21350
Active integrated antenna using T‐shaped microstip‐line‐fed slot antenna
Authors: Choi Dong‐Hyuk , Park Seong‐Ook
Published: December 2005

An active integrated antenna (AIA), which consists of a T‐shaped microstrip‐line‐fed slot antenna, is proposed. Since the designed antenna has an electromagnetically coupled feedback loop, it can easily solve the problem of DC isolation between ports of the amplifier. The fabricated parallel feedback antenna oscillator shows stable oscillation at a frequency of 10.05 GHz. The measured EIRP is 37.79 mW, and the cross‐polarization levels are at least −15‐dB lower than those of co‐polarization for all directions. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 367–370, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21351
Application of the defected microstrip structure as a tuning technique for rectangular printed antennas
Authors: Tirado‐Mendez J. A. , Jardón‐Aguilar H. , Iturbide‐Sanchez F.
Published: December 2005

The present work establishes the use of the defected microstrip structure (DMS) as a novel method of tuning the central frequency of rectangular printed antennas. The error obtained from the predicted operating frequency and the measured one is less than 4%, without degrading the VSWR, radiation pattern, and antenna gain. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 370–373, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21352
Study of parallel coupled‐line microstrip filter in broadband
Authors: Chen Chia‐Chung , Kuo Jen‐Tsai , Jiang Meshon , Chin Albert
Published: December 2005

A parallel coupled‐line microstrip filter is designed and implemented on PCB with its maximum bandwidth. In this paper, this filter has presented almost very good characteristics including the simulated bandwidth of 67%, the measured bandwidth of 64%, lower insertion loss of 1.27 dB, and flat response in the pass‐band. The maximum bandwidth fabricated on PCB shows good agreement with the theoretically calculated bandwidth of 70% due to the narrower gap size between the coupled lines. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 373–375, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21353
Practical impedance matching using genetic programming
Authors: Su Y. K. , Hou H. S. , Chang S. J.
Published: December 2005

A genetic programming method for impedance matching is presented. The method is applied to an impedance‐matching problem where the element values available are restricted to a set of preferred values. The experimental results show that this method can effectively generate practical and economical solutions. Since it can additionally deal with other design considerations, this method is useful for practical impedance matching. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 375–377, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21354
Dual‐wideband rectangular dielectric resonator antenna for WLAN communications
Authors: Lim E. H. , Leung K. W.
Published: December 2005

A dual and wideband single‐element rectangular dielectric resonator antenna (DRA) excited by a microstrip aperture is investigated experimentally. It provides two passbands in the ranges of 2.21–2.855 GHz and 4.385–5.455 GHz, which are popular bands for wireless local‐area networks (WLANs). The return loss, antenna gain, and radiation patterns of the proposed configuration are measured. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 378–380, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21355
Measured patterns of a resistive V‐dipole fed with a double‐Y balun
Authors: Venkatesan Jaikrishna , Scott Waymond R.
Published: December 2005

The performance of a double‐Y balun feeding a resistive V‐dipole is evaluated via antenna‐pattern measurements. An optical link is constructed for containing the feedline radiation to a laser receiver unit and the antenna under test (AUT), hence avoiding the uncertainty caused by cable radiation in a conventional antenna pattern‐measurement setup. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 380–383, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21356
Path‐loss characteristics in subway tunnels at 2.65 GHz
Authors: Choi Myung‐Sun , Kim Do‐Youn , Jo Han‐Shin , Yook Jong‐Gwan , Park Han‐Kyu
Published: December 2005

This paper presents the measurement of electromagnetic wave propagation in subway tunnels at f =2.6425GHz. The main goal of this work is to obtain more accurate knowledge of the propagation characteristics in straight and curved tunnels. Measurements have been conducted in four different types of tunnel courses: a straight tunnel, two curved tunnels (with 245‐m and 500‐m radius of curvature, respectively), and a tunnel that has both straight and curved sections. From the measured results, we analyze and compare the differences between the straight and curved tunnels, particularly with regard to path loss and the effect of path loss arising from different curvatures, and the characteristics of the combined tunnel (the straight and curved tunnel). The findings presented here should prove helpful in the estimation of link budget for satellite DMB service in tunnels and the determination of accurate propagation characteristics in tunnels. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 383–386, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21357
Improving the performance of double‐pass EDFA utilizing chirped bragg grating as feedback loop
Authors: Jamaludin M. Z. , Bakar A. A. A. , Naji A. W. , Rahman F. A. , Mahdi M. A. , Abdullah M. K.
Published: December 2005

A new dispersion‐compensated double‐pass erbium‐doped fiber amplifier (EDFA) with high gain and improved noise‐figure characteristics is demonstrated using chirped fiber Bragg grating. The performance is compared with that of the conventional double‐pass EDFA. The signal gain is improved by as much as 18.6 dB at −40‐dBm signal power with negligible noise penalty. The proposed amplifier architecture can improve the signal gain and at the same time compensate the signal dispersion. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48:386‐388, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21358
Highly efficient anti‐stokes generation in irregularly multicore microstructure fiber with double zero‐dispersion wavelengths
Authors: Yan Pei‐Guang , Li Yi‐Gang , Ding Lei , Zhang Wei , Lu Ke‐Cheng , Jia Ya‐Qing , Zhang Tie‐Qun , Zhu Xiao‐Nong , Su Hong‐Xin , Guo Qin‐Lin
Published: December 2005

In this work, we demonstrate highly efficient anti‐Stokes signal generation inside an irregular multicore microstructure fiber, using unamplified femtosecond laser pulses. For this special type of fiber, there are randomly distributed cores with a diameter ranging from 0.6 to 1.5 μm. We have observed a large ratio of the amplitude of the anti‐Stokes wave to that of the pump wave in the output spectrum. Our simulation results indicate that the features of the two zero‐dispersion wavelengths of the fiber are responsible for meeting the phase‐matching condition of four‐wave mixing, which produces the observed large anti‐Stokes wave. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 389–393, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21359
ZT‐ADIPML: Unconditionally stable PML algorithm for FDTD simulations
Authors: Ramadan Omar
Published: December 2005

Unconditionally stable formulations of the perfectly matched layer (PML) are presented for truncating linear dispersive finite‐difference time‐domain (FDTD) grids. In the proposed formulations, the 𝒵‐transform theory is employed in the alternating‐direction implicit FDTD (ADI‐FDTD) algorithm to obtain update equations for the field components in dispersive media. The validity of the proposed formulations is shown through a numerical example carried out in 1D linear Lorentz dispersive FDTD domain. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 393–396, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21360
New method for analysis of microstrip with finite‐width ground plane
Authors: Svacina Jiri
Published: December 2005

The paper contains an investigation of microstrips with finite‐width ground plane. The conformal mapping method and a new method of the so‐called moving perfect electric wall (MPEW) are used to obtain simple analytical relations for quasi‐TEM parameters. The computed results are compared with available data from other authors obtained through various numerical methods. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 396–399, 2006; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/mop.21361
A miniaturized antenna for 2G/3G frequency‐band applications
Authors: Borowiec Robert , Słobodzian Piotr M.
Published: December 2005

A novel miniaturized printed monopole antenna suitable for cellular handset terminals is presented. A substantial reduction in antenna size was achieved due to the use of the inverted‐F antenna concept combined with a capacitive feeding system. The antenna operates in three frequency bands, that is, GSM 1800, PCS 1900, and UMTS, with VSWR ≤2.5. The compactness of the antenna structure allows it to be placed on the top as well as the bottom of a handset. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 399–402, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21362
A new bi‐faced log periodic printed antenna
Authors: Ávila‐Navarro E. , Blanes J. M. , Carrasco J. A. , Reig C. , Navarro E. A.
Published: December 2005

In this paper, a new design of a broadband planar printed antenna based on the academic log periodic antenna is presented. The antenna consists of a series of printed dipoles, distributed on both faces of the substrate. Some configurations are explored, with a different number of printed dipoles. These are designed, simulated, fabricated, and measured. The calculated and measured return losses and radiation patterns are presented. The utility of the proposed antenna associated with its frequency bandwidth is better than 80%. The measured absolute gain is 6.5 dBi, and the front‐to‐back ratio is around 8 dB. The presented antenna should find wide applications in wireless communication systems and phased arrays. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 402–405, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21363
Microstrip stepped‐impedance hairpin resonator low‐pass filter with defected ground structure
Authors: Cho Ju‐Hyun , Lee Jong‐Chul
Published: December 2005

In this paper, a new microstrip stepped‐impedance hairpin resonator (SIR) low‐pass filter (LPF) using a defected ground structure (DGS) is proposed. The proposed SIR hairpin low‐pass filter using DGS provides a very sharp cutoff frequency response with low insertion loss. Furthermore, the SIR hairpin low‐pass filter can provide attenuation poles for the wide‐stopband characteristic due to the resonance characteristic of the DGS. Design parameters for the SIR low‐pass filter are derived based on stepped‐impedance theory and the equivalent‐circuit model for the DGS. The experimental results show excellent agreement with the theoretical simulation results. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 405–408, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21364
Retrodirective array for RFID and microwave tracking beacon applications
Authors: Chiu L. , Yum T. Y. , Chang W. S. , Xue Q. , Chan C. H.
Published: December 2005

A novel and compact four‐element retrodirective array (RDA) prototype is realized. It demonstrates excellent performance in terms of retrodirectivity and sensitivity. Each element employs a phase conjugator (a biased FET mixer) with a conversion gain of 5.46 dB. The LO is set at 19.61 GHz and is pumped into the element while the RF operates at 9.8 GHz. The mixer generates an IF signal with a frequency offset of 10 MHz from the RF to separate the transponded signal from the interrogating signal. Retrodirectivity is observed over a wide range of incidence angles from −50° to +50°. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 409–411, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21365
Urgency degree and bladder contraction velocity: Sequential changes in women with idiopathic detrusor overactivity
Authors: Cucchi A. , Quaglini S. , Siracusano S. , Rovereto B.
Published: December 2005

Aims

In patients with idiopathic detrusor overactivity (DO) who showed storage symptoms worsening with time, we checked whether and which urodynamic parameter changes are associated with an increased urgency degree.

Materials and Methods

We analyzed retrospectively the urodynamic findings in 54 women −27 with storage symptoms (Group A, mean age 32 ± 7 years) and 27 controls (Group B, mean age 30 ± 9 years). These latter had a history of recurrent UTIs (urinary tract infections), but when seen by us had no UTI, DO, lower urinary tract symptoms, or any other pathological finding. Group A had a first urodynamic examination when first referred (time 1) and were re‐assessed a mean of 16 months later (time 2) for worsened storage symptoms.

Results

In Group A, an idiopathic DO was shown at both times 1 and 2; urgency of voiding could be delayed during cystometry for ≥2 min (= moderate urgency) at time 1 and for <2 min (= severe urgency) at time 2; detrusor contraction strength or contractility proved higher than in Group B (P < 0.001) and increased from time 1 to time 2 (P < 0.001), detrusor shortening velocity being always the major component of the higher contractility levels.

Conclusions

A DO‐related increase in bladder contractility may have been further enhanced by severe urgency through a positive feedback mechanism. The urgency degree proved closely associated in DO patients with the level of detrusor shortening velocity rather than with detrusor pressure. Neurourol. Urdynam. © 2005 Wiley‐Liss, Inc.
Optimal production and maintenance policy for imperfect production systems
Authors: Wang Chih‐Hsiung
Published: December 2005

A joint optimization of the production run length and preventive maintenance (PM) policy is studied for a deteriorating production system where the in‐control period follows a general probability distribution with non‐decreasing failure rate. In the literature, the sufficient conditions for the optimality of the equal‐interval PM schedule is explored to derive an optimal production run length and an optimal number of PM actions. Nevertheless, an exhaustive search may arise. In this study, based on the assumption that the conditions for the optimality of the equal‐interval PM schedule hold, we derive some structural properties for the optimal production/PM policy, which increases the efficiency of the solution procedure. These analyses have implications for the practical application of the production/PM model to be more available in practice. A numerical example of gamma shift distribution with non‐decreasing failure rates is used to illustrate the solution procedure, leading to some insight into the management process. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006
Preparation, swelling behaviors and application of polyacrylamide/attapulgite superabsorbent composites
Authors: Zhang Junping , Liu Ruifeng , Li An , Wang Aiqin
Published: January 2006

A series of superabsorbent composites, polyacrylamide/attapulgite (PAMA), were prepared from acrylamide (AM) and attapulgite micropowder in aqueous solution, using N,N′‐methylenebisacrylamide (MBA) as a crosslinker and ammonium persulfate (APS) as an initiator and then saponified with sodium hydroxide solution. This paper focuses on swelling behaviors of the PAMA superabsorbent composites in various saline solutions. The results indicate that saline solutions can weaken the swelling abilities of the PAMA compsites greatly. Water absorbency of the PAMA composites with 20 and 40 wt% attapulgite in aqueous chloride salt solutions has the following order: Li+ = Na+ = K+, Mg2+ > Ca2+ = Ba2+ all through the range of concentration investigated. However, swelling properties of the composites are complicated in CuCl2(aq), AlCl3(aq) and FeCl3(aq) solutions and are related to saline solutions concentration. The deswelling behavior of PAMA composites is more obvious in univalent chloride salt solutions than in divalent and trivalent ones. The influence of kind and valence of anions on swelling ability of the composites is limited and almost the same. Moreover, reswelling capability, practical water retention ability in sand soil of the composites and the effect of pH on water absorbency of the PAMA composites were investigated. The PAMA composite shows good water retention and reswelling ability in sand soil, and may be used as a recyclable water‐managing material for the renewal of arid and desert environment. Copyright © 2006 John Wiley & Sons, Ltd.
Functional Micropatterned Surfaces by Combination of Plasma Polymerization and Lift‐Off Processes
Authors: Brétagnol Frédéric , Ceriotti Laura , Lejeune Michaël , Papadopoulou‐Bouraoui Andri , Hasiwa Marina , Gilliland Douglas , Ceccone Giacomo , Colpo Pascal , Rossi François
Published: December 2005

Summary: In this study, microstructured surfaces are produced by a spatial arrangement of different functional domains by a combination of plasma polymerization and photolithography. Two different kinds of protein and cell adhesive patterns have been alternated with non‐fouling areas. Non‐fouling patterns are made of poly(ethylene oxide) (PEO)‐like polymers obtained by pulsed plasma polymerization of diethylene glycol dimethyl ether, which leads to coatings with a high concentration of ethylene oxide groups (>70%). Fouling surfaces are composed of PEO coatings with a low concentration of ethylene oxide groups (≈40%) and films containing amino groups (from allylamine monomer) obtained by plasma polymerization. High pattern fidelity is demonstrated by ellispometry measurements, whereas XPS and ToF‐SIMS analyses have been used to characterize the surfaces. Experiments with a model protein (bovine serum albumin) and cells (L929 mouse fibroblasts) on patterned surfaces show that proteins and cells only adhere on the patterns, whereas the background stays uncovered.

Optical image showing the selective proliferation of L929 mouse fibroblast cells after culture on a pulsed PEO‐like/PAL micropatterned surface.

magnified image

Optical image showing the selective proliferation of L929 mouse fibroblast cells after culture on a pulsed PEO‐like/PAL micropatterned surface.
BIODECON: Plasma Decontamination in Medical Technology
Authors: Awakowicz Peter , von Keudell Achim
Published: December 2005

Plasma News: This section contains news of the plasma community all over the world. Articles about, for example, people, projects, and market trends are welcome. Suggestions should be sent to the editorial office of the Plasma Processes and Polymers, preferably by E‐mail to plasma@wiley‐vch.de. The editorial office decides which articles will be published.
Electrostatic interactions of peptides flanking the tyrosine kinase domain in the epidermal growth factor receptor provides a model for intracellular dimerization and autophosphorylation
Authors: Aifa Sami , Miled Nabil , Frikha Fakher , Aniba Mohamed R. , Svensson Samuel P.S. , Rebai Ahmed
Published: December 2005

The mechanism by which ligand‐activated EGFR induces autophosphorylation via dimerization is not fully understood. Structural studies have revealed an extracellular loop mediated receptor dimerization. We have previously presented experimental data showing the involvement of a positive 13 amino acid peptide (R645–R657; P13+) from the intracellular juxtamembrane domain (JM) of EGFR important for intracellular dimerization and autophosphorylation. A model was presented that suggest that P13+ interacts with a negative peptide (D979–E991; P13−) positioned distal to the tyrosine kinase domain in the opposite EGFR monomer. The present work shows additional data strengthening this model. In fact, by analyzing protein sequences of 21 annotated ErbB proteins from 9 vertebrate genomes, we reveal the high conservation of peptides P13+ and P13− with regard to their sequence as well as their position relative to the tyrosine kinase (TK) domain. Moreover in silico structure modeling of these ErbB intracellular domains supports a general electrostatic P13+/P13− interaction, implying that the C‐terminal of one receptor monomer is facing the TK domain of the other monomer in the receptor dimer and vice versa. This model provides new insights into the molecular mechanism of ErbB receptor activation and suggests a new strategy to pharmacologically interfering with ErbB receptor activity. Proteins 2006. © 2005 Wiley‐Liss, Inc.
Investigation of the electronic structure of the SbSeI cluster
Authors: Audzijonis A. , Žigas L. , Siroic J. , Pauliukas A. , Žaltauskas R. , Čerškus A. , Narušis J.
Published: January 2006

The energy levels of valence bands (VBs) and core levels (CLs) of SbSeI single crystals have been investigated theoretically. A molecular model of the SbSeI crystal was used for the calculations of VBs and CLs by the Hartree–Fock method (UHF). This molecular cluster consisting of 20 molecules was used for calculations of the total and of the averaged density of states including atom vibrations. The averaged total density of states is more similar to the experimental X‐ray photoelectron spectra (XPS). The cluster‐model calculations showed that the splitting of the CLs in SbSeI may be caused by photoelectron emission from the atoms at the surface which are in a different valence state. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of peptides in antimicrobial fractions of cheese extracts by electrospray ionization ion trap mass spectrometry coupled to a two‐dimensional liquid chromatographic separation
Authors: Losito Ilario , Carbonara Teresa , De Bari Maria Domenica , Gobbetti Marco , Palmisano Francesco , Rizzello Carlo Giuseppe , Zambonin Pier Giorgio
Published: January 2006

Electrospray ionization ion trap mass spectrometry (ESI‐ITMS) coupled to a two‐dimensional liquid chromatographic separation was applied to the identification of peptides in antimicrobial fractions of the aqueous extracts of nine Italian cheese varieties. In particular, the chromatographic fractions collected during a preliminary fast protein liquid chromatography (FPLC) separation on the cheese extracts were assayed for antimicrobial activity towards Lactobacillus sakei A15. Active fractions were subsequently analyzed by reversed‐phase high‐performance liquid chromatography electrospray ionization sequential mass spectrometry (HPLC/ESI)‐ITMSn, with n up to 3. Peptide identification was then performed starting from a conventional proteomics approach based on tandem mass spectrometric (MS/MS) analysis followed by database searching. In many cases this strategy had to be integrated by a careful correlation between spectral information and predicted peptide fragmentation, in order to reach unambiguous identifications. When even this integrated approach failed, MS3 measurements provided decisive information on the amino acid sequence of some peptides, through fragmentation of pendant groups along the peptide chain. As a result, 45 peptides, all arising from hydrolysis of milk caseins, were identified in nine antimicrobial FPLC fractions of aqueous extracts obtained from five of the nine cheese varieties considered. Many of them corresponded to peptides already known to exhibit biological activity. Copyright © 2006 John Wiley & Sons, Ltd.
Differentiation of monoiodothyronines using electrospray ionization tandem mass spectrometry
Authors: Zhang Yuntao , Conrad Abigail H. , Thoma Rudy , Conrad Gary W.
Published: January 2006

In this work two monoiodothyronines, 3‐T1 and 3′‐T1, have been analyzed using electrospray ionization tandem mass spectrometry (ESI‐MS/MS). Fragmentation patterns were proposed based on our data obtained by ESI‐MS/MS. MS2 spectra in either negative or positive ion mode can be used to differentiate 3‐T1 and 3′‐T1. Based on the relative abundance of fragment ions in MS2 spectra in the negative ion mode, quantification of the 3‐T1 and 3′‐T1 isomers in mixtures is achieved without prior separation. Solid‐phase extraction in combination with ESI‐MS/MS provides a practicable procedure that can be used to determine the molar ratio of 3‐T1 and 3′‐T1 in human serum with an error less than 3%. The detection limits for 3‐T1 and 3′‐T1 were 0.5 and 0.7 pg/µL, respectively. Copyright © 2006 John Wiley & Sons, Ltd.