bluuebunny/crossref_metadata_2025 huggingface dataset:
Liver transplantation in hepatitis B core–negative recipients using livers from hepatitis B core–positive donors: A 13-year experience
Authors: Bohorquez Humberto E. , Cohen Ari J. , Girgrah Nigel , Bruce David S. , Carmody Ian C. , Joshi Shoba , Reichman Trevor W. , Therapondos George , Mason Andrew L. , Loss George E.
Published: March 2013

The use of livers from hepatitis B surface antigen–negative (HBsAg−)/hepatitis B core antibody–positive (HBcAb+) donors in liver transplantation (LT) for HBsAg−/HBcAb− recipients is still controversial because of a lack of standard antiviral prophylaxis and long-term follow-up. We present our 13-year experience with the use of HBcAb+ donor livers in HBcAb− recipients. Patients received prophylaxis with hepatitis B immunoglobulin at the time of LT and then lamivudine daily. De novo hepatitis B virus (HBV) was defined as positive HBV DNA detection. Between January 1999 and December 2010, 1013 adult LT procedures were performed at our center. Sixty-four HBsAg−/HBcAb− patients (6.3%) received an HBsAg−/HBcAb+ liver. All donor sera were negative for HBcAb immunoglobulin M and HBV DNA. The mean follow-up was 48.8 ± 40.1 months (range = 1.2-148.8). Both the patient survival rates and the graft survival rates were 92.2% and 69.2% at 1 and 5 years, respectively. No graft losses or deaths were related to de novo HBV. Nine of the 64 patients (14.1%) developed de novo HBV. The mean time from LT to de novo HBV was 21.4 ± 26.1 months (range = 10.8-92.8 months). De novo HBV was successfully treated with adefovir or tenofovir. In conclusion, HBcAb+ allografts can be safely used in HBcAb− recipients without increased mortality or graft loss. Lifelong prophylaxis, continuous surveillance, and compliance are imperative for success. Should a de novo infection occur, our experience suggests that a variety of treatments can be employed to salvage the graft and obtain serum HBV DNA clearance. Liver Transpl 19:611–618, 2013. © 2013 AASLD.
Facile Fabrication of Multistimuli‐Responsive Metallo‐Supramolecular Core Cross‐Linked Block Copolymer Micelles
Authors: Ge Zhishen , Liu Shiyong
Published: March 2013

Metallo‐supramolecular core cross‐linked (CCL) micelles are fabricated from terpyridine‐functionalized double hydrophilic block copolymers, poly(2‐(2‐methoxyethoxy)ethyl methacrylate)‐b‐poly(2‐(diethylamino)ethyl methacrylate‐co‐4′‐(6‐methacryloxyhexyloxy)‐2,2′:6′,2″‐terpyridine) [PMEO2MA‐b‐P(DEA‐co‐TPHMA)] via the formation of bis(terpyridine)ruthenium(II) complexes. These metallo‐supramolecular CCL micelles exhibit not only high structural integrity under different pH values and temperatures in aqueous solution, but multistimuli responsiveness including pH‐responsive cores, thermo‐responsive shells, and reversible dissociation of bis(terpyridine)ruthenium(II) complexes upon addition of competitive metal ion chelator, which allows for precisely controlled release of the encapsulated hydrophobic guest molecules via the combination of different stimuli.

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Some inequalities involving eigenvalues of the Neumann Laplacian
Authors: Enache C. , Philippin G.A.
Published: March 2013

This paper is concerned with the eigenvalues of the Neumann Laplacian on various classes of domains of given measure: simply‐connected Lipschitz planar domains, n‐sided planar polygons and smooth N‐dimensional domains. In each case, we consider some quantities involving low eigenvalues of the Neumann Laplacian for which we obtain new inequalities. Moreover, we sharpen a universal bound derived by M. Ashbaugh and R. Benguria for sum of reciprocal of Neumann eigenvalues. Our investigations make use of some properties of conformal mappings, Bessel functions, symmetric domains or some isoperimetric inequalities for moments of inertia. Copyright © 2013 John Wiley & Sons, Ltd.
On the Cauchy problem for the two‐component b‐family system
Authors: Zhu Min , Xu Junxiang
Published: March 2013

In this paper, we establish the local well‐posedness for the two‐component b‐family system in a range of the Besov space. We also derive the blow‐up scenario for strong solutions of the system. In addition, we determine the wave‐breaking mechanism to the two‐component Dullin–Gottwald–Holm system. Copyright © 2013 John Wiley & Sons, Ltd.
Multiple solutions for a semilinear elliptic system in
Authors: Li Gongbao , Wang Chunhua
Published: March 2013

In this paper, we study the following semilinear elliptic system
urn:x-wiley:01704214:media:mma2764:mma2764-math-0001 where N > 2, f(x,t) and g(x,t) are continuous functions and satisfy additional conditions. By using critical point theory of strongly indefinite functionals, we obtain a positive ground state solution and infinitely many geometrically distinct solutions when f(x,t) and g(x,t) are periodic in X and odd in t. Copyright © 2013 John Wiley & Sons, Ltd.
Existence and uniqueness for a nonlinear inverse reaction‐diffusion problem with a nonlinear source in higher dimensions
Authors: Akyildiz Fahir Talay , Tatar Salih , Ulusoy Suleyman
Published: March 2013

This paper analyzes the existence and the uniqueness problem for an n‐dimensional nonlinear inverse reaction‐diffusion problem with a nonlinear source. A transformation is used to obtain a new inverse coefficient problem. Then, a parabolic differential operator Lλ is defined to establish the relation between the solution of Lλ = 0 and the new inverse problem. Following this, it is shown that the inverse problem has at least one solution in the class of admissible coefficients. Furthermore, it is proved that this solution is the unique solution of the undertaken inverse problem. A numerical example is given to illustrate ill‐posedness of the inverse problem. Copyright © 2013 John Wiley & Sons, Ltd.
Solutions of nonperiodic super quadratic Hamiltonian systems
Authors: Ding Jian , Zhang Fubao , Feng Guizhen
Published: March 2013

This paper concerns solutions for the Hamiltonian system: , where H(t,u) = 1 ∕ 2Lu ⋅ u + W(t,u), L is a 2N × 2N symmetric matrix, and . We consider the case that 0 ∉ σc( − (Jd ∕ dt + L)) and W satisfies some new generalized super quadratic condition different from the type of Ambrosetti–Rabinowitz. The method is variational: By virtue of some auxiliary system related to the ‘limit equation’ of the Hamiltonian system, we first establish that (C)c‐condition holds true for all c less than the least energy of the limit equation. Then, using some weak linking theorem recently developed, we obtain one least energy solution of the Hamiltonian system. Copyright © 2013 John Wiley & Sons, Ltd.
Legendre–Gauss–Lobatto spectral collocation method for nonlinear delay differential equations
Authors: Li‐jun Yi , Zi‐qiang Liang , Zhong‐qing Wang
Published: March 2013

A Legendre–Gauss–Lobatto spectral collocation method is introduced for the numerical solutions of a class of nonlinear delay differential equations. An efficient algorithm is designed for the single‐step scheme and applied to the multiple‐domain case. As a theoretical result, we obtain a general convergence theorem for the single‐step case. Numerical results show that the suggested algorithm enjoys high‐order accuracy both in time and in the delayed argument and can be implemented in a robust and efficient manner. Copyright © 2013 John Wiley & Sons, Ltd.
Controllability of Boolean control networks with impulsive effects and forbidden states
Authors: Liu Yang , Chen Hongwei , Wu Bo
Published: March 2013

This paper investigates the controllability of Boolean control networks (BCNs) with impulsive effects while avoiding certain forbidden states. Using semi‐tensor product of matrices, the BCNs with impulsive effects can be converted into impulsive discrete‐time systems. Then, some necessary and sufficient conditions for the controllability are obtained. It is interesting to find that impulsive effects play an important role in the controllability of BCNs. Finally, an example is given to show the efficiency of the obtained results. Copyright © 2013 John Wiley & Sons, Ltd.
A study on the systems of the Volterra integral forms of the Lane–Emden equations by the Adomian decomposition method
Authors: Wazwaz Abdul‐Majid , Rach Randolph , Duan Jun‐Sheng
Published: March 2013

In this paper, we introduce systems of Volterra integral forms of the Lane–Emden equations. We use the systematic Adomian decomposition method to handle these systems of integral forms. The Volterra integral forms overcome the singular behavior at the origin x = 0. The Adomian decomposition method gives reliable algorithm for analytic approximate solutions of these systems. Our results are supported by investigating several numerical examples. Copyright © 2013 John Wiley & Sons, Ltd.
A microstrip bandpass filter based on inductive coupled quarter‐wavelength resonators
Authors: Cheng Fei , Lin Xianqi , Zhang PengCheng , Song Kaijun , Fan Yong
Published: March 2013

This article proposes a compact filter using inductive coupled quarter‐wavelength resonators.The coupling between the quarter‐wavelength resonators is realized by a short‐end stub which behaves as a K‐inverter. As a result, the coupling coefficient of the resonators can be easily controlled by the length of the short‐end stub. A fourth‐order filter is designed and fabricated to demonstrate the proposed method. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1031–1033, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27469
Active GaN MMIC diplexer based on distributed amplification concept
Authors: Mata‐Contreras Javier , Palombini Diego , Martín‐Guerrero Teresa M. , Bentini A. , Camacho‐Peñalosa Carlos , Limiti Ernesto
Published: March 2013

A review of the fundamentals of distributed amplification is presented along with the design and performance of a novel dual‐band/diplexer monolithic distributed amplifier based on the combination of CRLH and RH transmission lines. The MMIC prototype, operating in the C‐band and featuring a 10 dB gain with less than −20 dB crosstalk levels, represents the first monolithic implementation in GaN technology for this type of topology. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1041–1045, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27471
Quasi‐elliptic slotline bandpass filter using a novel feeding scheme
Authors: Zhou Li‐Heng , Chen Jian‐Xin , Tang Hui , Jin Shi , Bao Zhi‐Hua
Published: March 2013

A novel uniplanar slotline bandpass filter with quasi‐elliptic response based on the half‐wavelength split ring resonators with internal coupling is proposed by using the coplanar waveguide (CPW)‐to‐slotline transition which is regarded as a part of the filter.The transition not only fulfils good impedance transformation characteristic without extra impedance matching circuit, but also controls the external quality factor flexibly. An equivalent circuit model is established to investigate the characteristic of the transition. The simulation and measurement results agree well. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1009–1011, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27473
A compact coupled‐line triple‐band bandpass filter with an adjustable third passband and open stubs
Authors: Ko Wen , Her Man‐Long
Published: March 2013

This study proposes a novel structure for designing a simple triple‐band bandpass filter. This filter structure consists of two sets of coupled lines with the same line width plus two sections of open stubs and three transmission line sections of a single line width. The design and fabrication of the overall circuit structure are innovative and simple. The third resonance frequency (f3 of 8.9 GHz) was shifted to a lower frequency (6.5 GHz) by lengthening the two open stubs. The second resonance frequency (f2 of 4.2 GHz) can be adjusted using the transmission line gap size. The first resonance frequency (f1 of 2.4 GHz) can be adjusted using the coupled line length. These filters were simulated using the IE3D full‐wave electromagnetic simulator, and the prototype of the bandpass filter was fabricated and measured. Comparisons of the simulated results and experimental data are presented. The findings show that the simulated results can match actual measured results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:970–975, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27475
Uplink transmission in the W‐band (75–110 GHz) for hybrid optical fiber‐wireless access networks
Authors: Pang Xiaodan , Deng Lei , Dogadaev Anton , Zhang Xu , Yu Xianbin , Monroy Idelfonso Tafur
Published: March 2013

We report on an experimental, W‐band, uplink for hybrid fiber‐wireless systems which enables high speed communication from the wireless end users to the central server. Overall system performances for an OFDM signal format are discussed in detail. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1033–1036, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27476
Millimeter‐wave INP DHBT power amplifier based on power‐optimized cascode configuration
Authors: Johansen Tom K. , Yan Lei , Dupuy Jean‐Yves , Nodjiadjim Virginie , Konczykowska Agnieszka , Riet Muriel
Published: March 2013

This letter describes the use of a power‐optimized cascode configuration for obtaining maximum output power at millimeter‐wave (mm‐wave) frequencies for a two‐way combined power amplifier (PA). The PA has been fabricated in a high‐speed InP double heterojunction bipolar transistor technology and has a total active emitter area of 68.4 μm2. The experimental results demonstrate a small signal gain of 9.8 dB and saturated output power of more than 18.6 dBm at 72 GHz with a peak power‐added efficiency of 12%. The benefits of the power optimized cascode configuration over the standard cascode configuration at mm‐wave frequencies are confirmed by both simulations and experimental results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1178–1182, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27477
Single or multi notch bands applied to microstrip excited ultra‐wideband antennas with dielectric resonator antenna case
Authors: Sabouni Abas , Kishk Ahmed
Published: March 2013

A new technique is proposed to introduce a narrow notch band to UWB antennas excited by microstrip lines.The technique is applied to an UWB dielectric resonator antenna. A short circuit microstrip stub that is parasitically coupled to the microstrip line is used to create a stopband filter at the desired frequency. Several notch bands can easily be introduced as the length of the stub is related to the notch frequency. The technique is verified experimentally. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1066–1069, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27482
Fully‐integrated standing wave oscillator using composite right/left‐handed LC network
Authors: Jang Sheng‐Lyang , Lee Wei‐Hao , Hsue Ching‐Wen
Published: March 2013

This letter proposes a dual‐band CMOS voltage‐controlled oscillator (VCO) implemented with a distributed composite right/left‐handed (CRLH) LC network.The VCO consists of four units of left‐handed LC resonator stacked in series, the LC resonator in shunt with a pair of cross‐coupled transistors, and a varactor serving as frequency band switching element. The parasitic inductors turn the left‐handed LC network to a CRLH network. In the fundamental mode, the VCO operates at the high‐frequency band. In harmonic mode, the oscillator provides low‐frequency band outputs. The VCO exploits the multiple oscillation mode of the CRLH standing wave oscillator. The proposed VCO has been implemented with the TSMC 0.18 μm 1P6M CMOS technology. It can generate differential signals in the high‐band frequency range of 7.23–7.86 GHz and in the low‐band frequency range of 3.81–5.32 GHz. The die area of the VCO is 0.991 × 0.815 mm2. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:985–988, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27487
Low profile slot antenna with dual band‐notched function for UWB systems
Authors: Ojaroudi Mohammad , Ojaroudi Nasser
Published: March 2013

In this article, a new multi‐resonance slot antenna, with dual band‐notched performance for UWB applications is presented. In the proposed structure, by cutting a rotated C‐shaped slot on top of the ground plane, additional resonances are excited and hence much wider impedance bandwidth can be produced, especially at the middle band. To generate single band notch characteristics, we use a rotated C‐shaped parasitic structure in the ground plane. Also to achieve dual band notch function, we insert a rotated C‐shaped slot at square radiating stub. The measured results reveal that the presented dual band‐notched slot antenna offers a very wide bandwidth with two notched bands covering all the 5.2/5.8 GHz WLAN, 3.5/5.5 GHz WiMAX, and 4 GHz C bands. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:951–954, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27488
Coupling properties of directional couplers based on special waveguides
Authors: Rodríguez‐Esquerre Vitaly Felix , Rodrigues Fernandes de Oliveira Ana Júlia , Silva‐Costa Matheus , Uzêda‐Souza Lucas
Published: March 2013

The coupling characteristics of a novel kind of directional couplers composed by two parallel non‐conventional waveguides are theoretically analyzed in details.The coupling length as a function of the operating wavelength and their optical and geometrical parameters are determined by an efficient frequency domain finite element method. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:949–951, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27489
Design of broadband and high‐efficiency class‐E amplifier with pHEMT using a novel low‐pass microstrip resonator cell
Authors: Hayati Mohsen , Lotfi Ali
Published: March 2013

In this article, a high‐efficient class‐E amplifier design with low voltage and broadband characteristics using a novel Front Coupled Tapered Compact Microstrip Resonant Cell is presented. The proposed micorstrip resonator is used as the harmonic control network in order to suppress higher order harmonics, which obtained the optimized impedance matching for the fundamental and harmonics. The class‐E amplifier is realized from 0.7 to 1.8 GHz, and obtained the power added efficiency of 72.5–77.5%. The maximum value of Power added efficiency (PAE) is 79.7% with 11‐dBm input power at 1.5 GHz. The designed class‐E amplifier using the proposed harmonic control network gained 15.34% increment in PAE, and 25.6% reduction in the circuit size in comparison with the conventional class‐E amplifier. The simulation and measurement results show the validity of the proposed design procedure of the broadband class‐E amplifier using a novel microstrip resonator cell. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1118–1124, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27490
Wake‐up radio architecture utilizing passive down conversion mixing
Authors: Pursula Pekka , Viikari Ville , Saari Juha‐Matti
Published: March 2013

This letter describes a low‐energy wake‐up radio that is based on passive down conversion. The receiver activates when it receives two closely located frequencies that are down converted in the passive mixer. The down converted signal is applied to a low‐frequency wake‐up IC that provides an identification code and wakes up an active radio for further communication. This letter derives an expression for the voltage sensitivity of the mixer and verifies the concept experimentally at 2.45 GHz. The wake‐up radio consumes 6.8 μA at 3 V. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1038–1041, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27493
Semiconductor optical amplifier cavity length impact over data erasing/rewriting
Authors: Ribeiro Napoleão S. , Gallep Cristiano M. , Conforti Evandro
Published: March 2013

The erasing of optical carrier intensity modulation and posterior data rewriting are analyzed for two semiconductor optical amplifiers with different active lengths: 2 mm and 8 mm long.Input signal extinction ratios (ERin) varying from 3.5 dB up to 10 dB are tested for the downstream channel at different bit rates (from 7 Gb/s up to 56 Gb/s), followed by remodulation of the upstream channel at 7 Gb/s. The ultra‐long 8 mm device shows superior performance, working error‐free for bit rates up to 30 Gb/s, with negligible power penalties for moderate ERin. However, for high bit rates (>40 Gb/s) and high input extinction ratios (ERin = 10 dB), the 8 mm device shows error‐floor at BER = 10−6. In comparison, even for moderate ERin at 40 Gb/s, the 2 mm device already presents error‐floors at BER = 10−3. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:998–1001, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27496
An electrically small antenna with integrated DGS filter
Authors: Oukil Sofiane , Kimouche Hocine , Azrar Arab
Published: March 2013

In this letter, a dumbbell‐shaped defected ground structure is proposed to suppress higher order harmonics of an electrically small antenna.A slot loading technique is applied to a well‐known low‐profile antenna, and the area miniaturization of a rectangular microstrip patch antenna by inserting a number of slits parallel to the radiating edges is investigated in relation to the quality factor. The antenna was designed to operate at 0.95 GHz (GSM). Measurement results on a prototype antenna fully demonstrate the performance of the proposed antenna. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:962–966, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27498
Sixty‐GHz on‐chip bandpass filter designed with multiple split ring resonators
Authors: Mat Dayang A. A. , Pokharel Ramesh K. , Sapawi Rohana , Kanaya Haruichi , Yoshida Keiji
Published: March 2013

This article describes the design of on‐chip bandpass filter (BPF) with split ring resonators (SRRs) for millimeter wave application. SRR is one of the metamaterial structures commonly used in designing the passive component and is used to improve the performance of the device. In this design, the BPF is designed with two (2) and five (5) SRRs to analyze the effect of SRRs toward enhancing the performance of the BPF. The SRRs are constructed along the resonator line below the BPF structure on the second lowest metal. In this article, it is shown that the magnetic resonance frequency shifted and leaded to improvement in the insertion loss of BPF as the number of SRRs increased to five. For BPF with 5‐SRRs, the insertion loss is 2.02 dB with return loss better than 30 dB, whereas for BPF with only 2‐SRRs, the insertion loss is 3.29 dB with return loss better than 50 dB. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1182–1185, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27499
A novel low‐voltage tunable capacitor for tunable RF circuit applications
Authors: Lee Young Chul , Lee Baek Ju , Ko Kyung Hyun
Published: March 2013

In this article, a novel architecture of the tunable capacitor is proposed for low‐voltage applications. In order to reduce operation voltage by enhancing fringing electric fields, two finger‐patterned electrodes with zero spacing are vertically separated by employing a multilayer thin‐film dielectric of a para‐/ferro‐/para‐electrics. The proposed tunable capacitor was fabricated on a quartz wafer and its characteristics are analyzed in terms of effective capacitance and tunability with a function of applied voltages, in comparison with the tunable capacitor with the finger‐pattern electrode only on the top of the dielectric. At 8 V and 2 GHz, the proposed tunable capacitor shows a tunability of 18% that is 10.3% higher than that of the compared one. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1152–1155, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27500
The analysis of the effect of flicker noise on orthogonal frequency‐division multiplexing systems
Authors: Woo Sanghyun , Hur Joonhoi , Kim Hyoungsoo
Published: March 2013

In this article, we proposed a new flicker noise simulation methodology within an orthogonal frequency‐division multiplexing (OFDM) PHY layer, which offers accurate analyses of the flicker noise effect.To prove this effect, we examine bit error rate performance with flicker noise by generating raw and channel‐coded data. Experiment results are demonstrated using Reed Solomon channel coding. The proposed simulation methodology offers precise results for deciding flicker noise requirement on RF building blocks for OFDM systems. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1171–1174, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27502
Investigation on a compact ring printed monopole antenna for wireless implantable body area network (WiBAN) applications
Authors: Ramli Nur Hidayah , Kamarudin Muhammad Ramlee , Samsuri Nor Asmawati , Ahyat Ezla Najwa
Published: March 2013

The main objective of this article is to design a compact ring printed monopole antenna for WiBAN applications. The performance of antenna is measured based on gain, return loss, efficiency, radiation pattern, and operating bandwidth. The antenna is implanted into canola oil (for homogeneous material) and beef (for nonhomogeneous material). The final measured result shows satisfactory performance and good agreement with the simulated result. The result presented indicates that the gain of antenna is 0.8 dBi with 49% efficiency when antenna is implanted into canola oil, whereas the gain of antenna is −30 dBi with 0.04% efficiency when antenna is implanted into beef. The radiation patterns of antenna are changed depend on the size and material of human body model. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1053–1058, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27503
9.952‐Gb/s On/Off keying signal transmission over 92‐GHz radio‐over‐fiber system with 40‐km single‐mode fiber and 2‐m air link
Authors: Fang Yuan , Yu Jianjun , Chi Nan , Dong Ze , Chang Geekung K.
Published: March 2013

In this article, we experimentally demonstrated the transmission of 9.952‐Gb/s On/Off Keying (OOK) signal over 40‐km single‐mode fiber (SMF‐28) and 2‐m air link for 92‐GHz RoF system which is near 0.1 THz.We investigate the BER and eye diagram based on different transmission distance and pattern length. The results show that good performance is obtained. The error floor at 20 km and 40 km is 1×10−6 and 1×10−7 respectively when pattern length is 231‐1. However, there is no error floor up to 1×10−10 if pattern length is 27‐1. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1014–1017, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27505
A fully integrated 5.38–5.55 GHz low power cmos hartley voltage‐controlled oscillator
Authors: Huang Jhin‐Fang , Wei Tzyy‐Haur , Chen Kuo‐Lung
Published: March 2013

A fully integrated CMOS Hartley voltage controlled oscillator (VCO) applying in 5.6 GHz wireless receiver communication is successfully implemented by TSMC 0.18‐μm CMOS process.To reduce the phase noise, the proposed VCO adopts the tapped‐inductor technique, differential architecture, and symmetrical layout. No more integrated inductors are used for the buffer design to avoid magnetic coupling into the VCO core. At the supply voltage of 1.3 V, measured results achieve a tuning range of 5.38 to 5.55 GHz with a tuned voltage of 0 to 1.3 V, a phase noise of −115.4 dBc/Hz at 1 MHz frequency offset from the carrier frequency of 5.55 GHz and an output power of −6.3 dBm at 5.55 GHz. The power dissipation of the VCO is 3.77 mW and the chip area, including pads, is 0.51 (0.55 × 0.93) mm2. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:978–981, 2013; Microwave Opt Technol Lett 55:978–981, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27506
High isolation series‐shunt photoconductive microwave switch
Authors: Draskovic Drasko , Fernandez Jean Raphael Olivier , Briso‐Rodriguez Cesar
Published: March 2013

This article presents a wide band compact high isolation photoconductive switch, which is based on the series‐shunt switch design with three photoconductive switches made of diced high‐resistivity silicon wafer placed over a microstrip gap and activated by 808‐nm near‐infrared laser diodes. The switch shows an insertion loss of 1.2 dB and an isolation of 44.8 dB at 2 GHz. It is easy to operate and control by light, high‐speed, electromagnetically transparent and it does not require any biasing circuits. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1168–1170, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27507
Ultra‐wideband bandpass filter using simplified dual composite right/left‐handed transmission line structure
Authors: Wang Cheng , Shi Yongrong , Liu Sheng , Tang Wanchun
Published: March 2013

A simplified dual composite right/left‐handed (SD‐CRLH) transmission line (TL) structure is proposed and analyzed in this article.The SD‐CRLH TL with only capacitor in series is a left‐handed (LH) highpass filter, while the SD‐CRLH TL with only inductor in series is a right‐handed (RH) lowpass filter. By combining them together, a bandpass filter (BPF) can be realized. As an example, an ultra‐wideband (UWB) BPF is designed and simulated using the SD‐CRLH TL structures, and finally fabricated by the standard printed circuit board process. The measurements show that the proposed UWB BPF has a passband from 3.1 to 10.6 GHz with a group delay variation of less than 0.13 ns, and the insertion loss is less than 1.5 dB over the passband. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1165–1167, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27508
Circularly polarized annular slot antenna with switchable frequency
Authors: Wang Chuen‐Ching , Chen Mu‐Yi , Row Jeen‐Sheen
Published: March 2013

A design for frequency reconfigurable annular slot antennas with circular polarization (CP) is described.The slot antenna is excited with a shorted microstrip line through coupling, and one varactor diode placed on the slot is used to generate CP radiation. By controlling the dc bias of the varactor, the CP operating frequency of the slot antenna can be switched between two frequencies with a frequency ratio of about 1.6; moreover, the antenna operating at each CP frequency has a return loss of less than 10 dB and the broadside radiation with a peak gain of higher than 3 dB. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1115–1118, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27509
Small pifa for ZigBee and wlan application
Authors: Tseng Ching‐Fang , Chen Yi‐Wen
Published: March 2013

A multiband printed PIFA with an I‐shaped strip and an inverted L‐shaped strip, to be electromagnetic compatible with a nearby conducting box, has been proposed. By introducing a T‐shaped strip, the upper band in the WLAN and HIPERLAN/2 bands is obtained. The proposed antenna is successfully simulated, designed, and measured, showing good matched impedance, omnidirectional radiation pattern, and constant gain. For return loss less than 10 dB, the proposed antenna operates at lower band with a bandwidth of 150 MHz for ZigBee operation, and at upper band with a bandwidth of 800 MHz for WLAN and HIPERLAN/2 applications. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1074–1077, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27511
Dual‐band notched ultra‐wideband antenna by using step‐by‐step design inside conductor‐backed plane
Authors: Esmati Zahra , Moosazadeh Mahdi
Published: March 2013

A coplanar waveguide fed (CPW‐fed) ultra‐wideband antenna with dual band‐notched characteristics is proposed. The main features of the proposed antenna are the compact dimensions and band‐notched characteristics that are achieved without modifying the radiator or the CPW‐ground plane. Dual band‐notched characteristics are achieved by M‐shaped strip inside the slotted conductor‐backed plane. Also, wider impedance bandwidth can be achieved with this structure. The measured results show that the proposed antenna operates over the frequency band between 2.6 GHz and 11.7 GHz (127%), defined by VSWR < 2, except two notched bands (3.25–4.32 GHz and 5.02–5.97 GHz), where the VSWR is more than eight, aimed at suppressing any interference from IEEE802.16 WiMAX (3.3–3.6 GHz), C‐band (3.7–4.2 GHz), and IEEE802.11a WLAN (5.15–5.825 GHz). The designed antenna has a small size of 15 × 15 mm2. The antenna has a desirable VSWR level, radiation pattern and gain characteristics for ultra‐wideband frequency band range. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1069–1074, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27512
Role of optical coherence tomography for flexor tendon imaging in a rabbit model
Authors: Tay Benjamin Chia‐Meng , Chow Tzu‐Hao , Ng Beng Koon , He Min , Gan Aaron Wei‐Tat , Chong Alphonsus Khin‐Sze
Published: March 2013

Optical coherence tomography (OCT) was used to monitor various flexor tendon states including tendon at rest, normal tendons during loading, tendon microstructural damage post loading, and healing tendons at 0, 3, and 8 weeks time points.Potential uses include assessing microstructural damage, monitoring the quality of suture repair, and tendon healing. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:990–995, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27514
Cole–cole model for glucose‐dependent dielectric properties of blood plasma for continuous glucose monitoring
Authors: Karacolak Tutku , Moreland Elaine C. , Topsakal Erdem
Published: March 2013

In this study, we show a correlation between electrical properties (relative permittivity–εr and conductivity–σ) of blood plasma and plasma glucose concentration. In order to formulate that correlation, we performed electrical property measurements on blood samples collected from 10 adults between the ages of 18 and 40 at University of Alabama Birmingham (UAB) Children's hospital. The measurements are conducted between 500 MHz and 20 GHz band. Using the data obtained from measurements, we developed a single‐pole Cole–Cole model for εr and σ as a function of plasma blood glucose concentration. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1160–1164, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27515
Compact microstrip antenna for mobile communication
Authors: Chatterjee Samiran , Ghosh Kalyanbrata , Paul Joydeep , Chowdhury S.K. , Chanda (Sarkar) Debasree , Sarkar P.P.
Published: March 2013

A single layer, single feed compact rectangular microstrip antenna is proposed. Resonant frequency has been reduced drastically by cutting unequal rectangular slots at the edge of the patch. Two rectangular slots are introduced at the left and right side of the patch to reduce the resonant frequency. The widths of the rectangular slots are different to improve the gain bandwidth performance of the antenna. The antenna size has been reduced by 73.9% when compared to a conventional rectangular microstrip patch antenna. The characteristics of the designed structure are investigated by using Method of Moment‐based electromagnetic solver, IE3D. There is a reasonable agreement between these simulated data and measured values. An extensive analysis of the return loss, radiation pattern, gain, and efficiency of the proposed antenna is shown in this paper. The simple configuration and low profile nature of the proposed antenna leads to easy fabrication and make it suitable for the applications in Wireless communication system. Mainly, it is developed to operate in the mobile communication range of 900 MHz–1.8 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:954–957, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27517
Design and implemention of very compact band‐stop filter with petal‐shaped stub for radar applications
Authors: Ojaroudi Nasser , Ojaroudi Mohammad , Habibi Reza
Published: March 2013

In this article, we introduce a compact microstrip band stop filter (BSF) at X‐band frequency range and this shall be used in local oscillator chain for X‐band transceiver. Presented microstrip filter consists of a transmission line with a petal‐shaped stub and a ground plane with a modified rectangular‐shaped defected ground structure (DGS). Operation frequencies of the filter can be easily controlled by changing four protruded T‐shaped strips in the petal‐shaped structure. The DGS slot evolved from photonic band gap (PBG) is embedded to achieve a good impedance matching and the required filter's characteristics. The proposed band‐stop filter has wide bandwidth from 8–12 GHz for X‐band Communications that can be used in Radar applications. Good agreement between simulated and measured results cause that excellent stop‐band performance could be obtained through the X‐band frequency range. The proposed microstrip filter fabricated on a Rogers RT/Duroid 5880 substrate with a relative dielectric constant of 2.2 and has a very small size of 10 × 15 mm2. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1130–1132, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27518
Indoor positioning based on global positioning system signals
Authors: Ozsoy Kerem , Bozkurt Ayhan , Tekin Ibrahim
Published: March 2013

The Global Positioning System (GPS) is highly reliable and accurate when used outdoors.However, in indoor environments, due to the additional signal loss incurred by the walls of the buildings, the detection and decoding of GPS signals becomes a difficult task. As a solution to the indoor area coverage problem, an indoor positioning system based on GPS repeaters and a modified positioning algorithm is proposed, designed, and tested. A prototype indoor positioning system for 1D/2D positioning is built using directional GPS antennas and low‐noise amplifiers (LNA). The modified positioning algorithm is used for the real time processing of captured live GPS data. All the system components are integrated and positioning is obtained for the evaluation of the system performance. Results of the experiments show that the proposed system can be used for indoor positioning in locations where there is no GPS signal reception. The proposed system facilitates the continuation of GPS services indoors with hardware additions to the buildings and only a software update to a standard GPS receiver. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1091–1097, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27520
Deep band‐notched ultra‐wideband planar monopole antenna using meander lines
Authors: Liu L. , Cheung S. W. , Yuk T. I.
Published: March 2013

The article presents the design of a planar ultra‐wideband (UWB) monopole antenna with a deep band‐notched characteristic. The antenna has an elliptical radiator fed by a microstrip line and a small ground‐plane size of 30×15 mm2. Two pairs of meander lines (MLs) are employed to implement the deep band‐notched characteristic. One pair of the MLs is placed closely on both sides of the microstrip‐feed line with one of their ends shorted to ground. The other pair is placed at the upper edges of the ground plane on the other side of the substrate. The frequency range of the notched band can be controlled by the dimensions of the MLs. In our studies, the notched band is designed in the frequency band from 5.1 to 5.85 GHz to suppress the signals in the WLAN system. The antenna is studied and optimized using computer simulation. For verification of simulation results, the antenna is fabricated and measured. Results show that, by using the two pairs of MLs, the gain of the antenna at the notch frequency can be suppressed by 14 dB, with the efficiency reduced to less than 5%. Due to the small ground‐plane size used in the antenna, the feeding cable used for measurements in the measurement equipment has significant effects on the measured results. This leads to large discrepancies between the simulated and measured results at low frequencies. To study this, the model of the feeding cable is also included in simulation and the results show that the discrepancies are substantially reduced. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1085–1091, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27521
1.9 μm lasing with Tm3+/Yb3+ co‐doped air‐clad fiber and 931 nm pumping
Authors: Saidin N. , Halder A. , Ghosh D. , Pal M. , Paul Mukul Chandran , Bhadra S. K. , Ali S. M. M. , Damanhuri S. S. A. , Ahmad H. , Harun Sulaiman Wadi
Published: March 2013

A 1.9 μm single mode laser is demonstrated by employing a newly developed large mode area Tm3+/Yb3+ co‐doped air‐clad photonic crystal fiber (PCF) in conjunction with 931 nm pumping for the first time. The PCF has an Yb3+ and Tm3+ ion concentrations of about 16 × 10−19 and 4 × 10−19 ions/cc, respectively. The laser produces a maximum output power of 4.6 mW with an efficiency slope of 0.70% at a multimode pump power of 2.3 W with a 2.7 m long PCF in a linear cavity with two fiber Bragg grating. The threshold of the input pump power is obtained at around 1.3 W. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1124–1126, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27523
Compact CMOS branch‐line coupler using high‐Q slow‐wave transmission lines
Authors: Wang Sen , Huang Bo‐Zong
Published: March 2013

This article presents a miniaturized 90° coupler incorporating slotted conductor‐backed coplanar waveguide (S‐CBCPW) transmission lines (TLs) and four shunt capacitors. The periodically slotted ground achieves higher slow‐wave factor (SWF) or effective permittivity (εeff), and lower attenuation constant. Electrical characteristics of the S‐CBCPW TLs are investigated by different slotted ground layers. Moreover, trade‐offs among SWF, characteristic impedance, and electrical length for the design are also discussed. Finally, the measured 24‐GHz coupler not only features smallest normalized chip area among previously reported CMOS couplers but also demonstrates excellent results which are comparable to the designs at 60 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1174–1178, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27525
Demonstration of acoustic vibration sensor based on microfiber knot resonator
Authors: Sulaiman A. , Muhammad M. Z. , Harun S. W. , Arof H. , Ahmad H.
Published: March 2013

A compact microfiber‐based acoustic vibration sensor is demonstrated using microfiber knot resonator (MKR) structure, which is fabricated by flame brushing technique. It is observed that the extinction ratio of the resonant spectrum of the knot resonator is linearly proportional to the vibration amplitude. This is attributed to the interruption of the effective coupling of the MKR which is correlated with the exposed vibration force. It is also shown that the resonant wavelength shifts by about 0.19 nm as the normalized vibration energy is increased from 0 to 10%. The performance of the sensor is then further investigated by monitoring the fast Fourier transform (FFT) of the signal when the MKR is exposed to various vibration frequencies as a narrowband 1545 nm laser is injected into the MKR. In the spectra of the signals, the frequency of the applied vibration is clearly shown as it has the highest magnitude followed by the accompanying harmonics. This holds true for all vibration frequencies. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1138–1141, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27526
Broadband millimeter‐wave composite cavity backed antenna with bowtie exciter
Authors: Qu Shi‐Wei , Ng Kungbo
Published: March 2013

A wideband cavity‐backed antenna is proposed in this article.For performance improvement, an elliptical composite cavity is adopted and it is excited by a rounded bowtie dipole through a transition from a microstrip line to a parallel strip line. To reduce the fabrication errors, the antenna aperture is designed to be over 0.84 wavelength at the lowest operating frequency, and the exciter is built on a substrate along with the transition by the printed circuit board (PCB) techniques. Measurements show that the antenna can be operated in a frequency band of 30.6–70 GHz for SWR ≤ 2 and stable radiation patterns. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1101–1104, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27528
Circular polarization patch antenna design with diagonal periodic metallic via holes
Authors: Jin Cheng , Li Rui , Bao Xiao‐Yue
Published: March 2013

A circular polarization (CP) patch antenna is proposed for the first time in this article. The proposed antenna is developed based on a patch antenna combined with one row of diagonal periodic metallic via holes. By optimizing the location of the periodic metallic via holes, two orthogonal waves with 90° phase difference are excited using single feed and a CP patch antenna is obtained. A CP antenna is designed based on the proposed structure and simulated by Ansoft HFSS. The designed CP antenna is fabricated and measured. The measured results present return loss |S11| > 10 dB from 10.4 to 11.6 GHz. The radiation pattern is also measured, and it exhibits good circular polarization property with 3‐dB axial ratio (AR) of 1.2 dB and gain of 4.02 dBic. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett1100, 2013; 1097 this 1100 online at wileyonlinelibrary.com. DOI 10.1002/mop.27529
Metamaterial inspired fabry–pérot antenna with cascaded frequency selective surfaces
Authors: Brito Davi B. , d'Assunção Adaildo G. , Maniçoba Robson H. C. , Begaud Xavier
Published: March 2013

A Fabry–Pérot antenna can be realized by employing a frequency selective surface (FSS), with suitable frequency selective properties, placed at an adequate distance from a perfect electric ground plane, in our case the ground plane is a metamaterial high impedance surface (HIS). The FSS is a multilayer partially reflective surface (PRS) realized by a periodic distribution of metallic elements printed on a dielectric slab. It can almost entirely reflect incident waves. By inserting a patch antenna between the ground plane and the FSS, a highly directive antenna can be obtained. Metamaterials are artificial structures that can be designed to exhibit unusual electromagnetic properties not observed in natural materials. The HIS is a metamaterial structure. The HIS does not support propagating surface waves, and it reflects electromagnetic waves with no phase reversal. Simulated and experimental results are presented. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:981–985, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27531