bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concurrent dual‐band digital predistortion method for wideband power amplifier with large carrier spacing two‐carrier signal
Authors: Xiang Haixia , Yu Cuiping , Gao Jinchun , Li Shulan , Wu Yongle , Su Ming , Liu Yuanan 
Published: January 2014

ABSTRACTA concurrent dual‐band three‐layered biased memory polynomial (DB‐TLBMP) model is proposed for the linearization of wideband power amplifiers driven by large carrier spacing two‐carrier signals. The DB‐TLBMP model is derived by extending the TLBMP model to the concurrent dual‐band mode, and the least square algorithm is used for coefficients extraction of each layer. Using a two‐carrier wideband code division multiple access signal with 40‐MHz carrier spacing at 2.65 GHz, whose peak‐to‐average power ratio is 7.74 dB, the adjacent channel leakage ratios (ACLRs) improvement of more than 17 dBc are achieved to give the ACLRs below −50 dBc at the offset of ±5 MHz and an average output power of 37 dBm. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:594–597, 2014
Koch slot loop antenna for wireless body‐centric communication
Authors: Hebelka V. , Raida Z. 
Published: January 2014

ABSTRACTIn this article, we describe the design of a coplanar waveguide (CPW) fed Koch slot loop antenna with a tuning stub. The antenna is optimized to be used in a wireless body‐centric communication. The antenna is designed to operate in the ISM frequency band from 5.725 to 5.875 GHz (ITU‐R5.138, 5.150, and 5.280). The study shows properties of the antenna, from the viewpoint of impedance matching, and radiation patterns. The impedance matching at the resonant frequency can be acquired by a tuning stub. The designed CPW‐fed slot antenna exhibits a proper polarization, a low‐radiation loss, and a weaker dispersion. We experimentally prove that the designed antenna efficiently excites surface waves and creeping waves. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:764–766, 2014
Study on the empirical design of open‐ended coaxial cavity resonator
Authors: Lee Yun‐Min , Kim Jin‐Kook , Hur Jung 
Published: January 2014

AbstractThis article is a study of an empirical design of an open‐ended coaxial cavity resonator. The coaxial cavity resonator can be designed using the coaxial transmission‐line theory. It can be done by using the radius of the inner conductor, the inner radius, and the length of the resonator. However, the basic coaxial transmission‐line theory can be seen that the characteristics of the resonant frequency and the Q value are varied by the change of length, regardless of the value of radius of the inner conductor and inner radius of the resonator. We find out the impact of radius of the inner conductor, inner radius of the resonator, and the length of the resonator parameter and propose the optimized empirical resonator design method by reducing the error between the theoretical value and the design value. High frequency structure simulator was used for simulation and the material of the resonator was designed with a copper. Based on the simulation, several resonators are fabricated by the size of 14 mm for the radius of inner conductor, 2, 5, and 10 mm, respectively, for the inner radius of resonator, and 8.5 mm for the length of the resonator. The resonant frequencies of the produced resonators were measured at 6.1, 5.7, and 6.5 GHz, respectively. According to the result of simulation and measurement, we know that we can design the relatively exact open‐ended coaxial cavity resonator by applying the basic coaxial transmission‐line theory directly when the length of the resonator is less than 10 mm, and adding the correction factor of 0.5 GHz to the calculated resonant frequency in case of more than 10 mm of the length of the resonator. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:606–610, 2014
Multi‐narrowband‐reconfigurable slot dipole antenna
Authors: Idris I. H. , Hamid M. R. , Jamaluddin M. H. , Rahim M. K. A. , Kassim N. M. , Majid H. A. , Mohamad H. 
Published: January 2014

ABSTRACTA new reconfigurable multiband antenna is presented. The antenna operates in triple band and can be switched to operate either in single or dual band. The multifrequency band is achieved by using slots dipole antenna fed by a coplanar waveguide (CPW). Six switches are used and positioned at specific locations in the slots to achieve frequency reconfigurability. The antenna reconfiguration is realized when the dipole arms are coupled or decoupled from the slot edges. Three different sub‐band frequencies (2.40, 3.50, and/or 5.20 GHz) are obtained. Measured and simulated results are presented. The proposed antenna may be suitable for future multimode applications such as cognitive radio systems. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:735–740, 2014
Performance enhancement of a wideband spiral antenna using a stepped ground plane
Authors: Mohamad Sarah , Cahill Robert , Fusco Vincent 
Published: January 2014

ABSTRACTThis study presents the use of a stepped ground plane as a means to increase the gain and front‐to‐back ratio of an Archimedean spiral which operates in the frequency range 3–10 GHz. The backing structure is designed to optimize the antenna performance in discrete 1 GHz bands by placing each of the eight metal steps one quarter wavelength below the corresponding active regions of the spiral. Simulated and experimental results show that this type of ground plane can be designed to enhance the antenna performance over the entire 105% operating bandwidth of the spiral. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:753–757, 2014
All‐fiber, versatile femtosecond soliton source with broad wavelength and repetition‐rate tuning ranges
Authors: Wei Yizhen , Hu Kai 
Published: January 2014

ABSTRACTWe demonstrate an all‐fiber, widely wavelength, and repetition‐rate tunable soliton source using soliton self‐frequency shift (SSFS) in a single‐mode fiber. A 2‐ps actively mode‐locked fiber laser at 1550 nm incorporating a Mach–Zehnder modulator is used as a repetition‐tunable input source. The SSFS process results in a compressed, wavelength‐tunable femtosecond pulse. Versatility of the source is demonstrated through tuning of soliton wavelength from 1560 to 1700 nm, as well as arbitrary pulse sequence generation. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:613–615, 2014
Planar dual‐ and tri‐band bandpass filters using single improved ring resonator and simple feed scheme
Authors: Xu Kai‐Da , Zhang Yong‐Hong , Fan Yong , Li Joshua Le‐Wei , Joines William T. , Liu Qing Huo 
Published: January 2014

AbstractA planar single improved dual‐mode ring resonator loaded by four mushroom‐shaped stubs based on a simple feed scheme is presented for design of dual‐ and tri‐band bandpass filters (BPFs). The simple pair of feed lines with source‐load coupling is used to not only feed the ring resonator but also generate the higher desired third passband when the length of feed lines changes. That is, a desired dual‐ or tri‐band BPF can be designed based on the same single‐ring resonator. For demonstration purpose, two experimental example filters have been fabricated and implemented. The simulated and measured results are presented and show good agreements. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:574–577, 2014
Broadband reflectarrays made of cells with three coplanar parallel dipoles
Authors: Florencio Rafael , Boix Rafael R. , Carrasco Eduardo , Encinar José A. , Barba Mariano , Pérez‐Palomino Gerardo 
Published: January 2014

ABSTRACTA broadband reflectarray cell made of three parallel dipoles printed on a dielectric layer is presented. A 33% bandwidth is achieved for the cell made of dipoles, which is larger than that obtained for a reference cell consisting of three stacked square patches (26%). Using this cell, a 41‐cm reflectarray antenna has been designed to produce a collimated beam at 9.5 GHz. The numerical results obtained for the reflectarray antenna made of parallel dipoles show a 1‐dB bandwidth of 19%, a 65% efficiency, 0.2 dB of losses, and low levels of cross polarization (25 dB below the maximum). These results demonstrate a high performance for the proposed reflectarray antenna made of cells with three printed dipoles. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:748–753, 2014
Linearity improvement analysis for power amplifiers at mm‐wave frequencies
Authors: Valliarampath Joe , Sinha Saurabh 
Published: January 2014

ABSTRACTThis article presents an adaptive predistortion (APD) linearization technique to improve the linearity of millimeter‐wave power amplifiers (PAs), specifically at 60 GHz. The PA and the APD were designed using the 0.13 µm SiGe BiCMOS process. The predistortion is applied to the PA by varying the gain of the PA through its variable gain amplifier. The PA achieves a PSAT of 11.97 dBm and
of −10 dBm. After linearization the PA has an improved
of −6 dBm. This linearization technique results in an optimum intermodulation distortion 3rd reduction of 10 dB. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:743–748, 2014
Computer‐aided design of millimeter‐wave continuous wave power combiner
Authors: Sarkar Mousumi , Bhanja Sukhendu , Majumdar Arijit 
Published: January 2014

ABSTRACTA two‐diode injection locked power combiner has been designed with computer‐aided design approach and experimentally tested. An output power of 25.48 dBm with a phase noise of −100 dBc/Hz for a frequency offset of 10 kHz from the carrier frequency of 34.6 GHz has been achieved. The power‐combiner cavity has been simulated with 3D full wave electromagnetic field simulator HFSS and cosimulated with the equivalent circuit of the continuous wave Gunn diode using ANSYS Designer. The experimental result closely matches with the simulation and is better than the analytical approach reported by earlier researchers. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:705–709, 2014
A planar compact metamaterial‐inspired broadband antenna
Authors: Anila P V , Indhu K K , Nijas C M , Sujith R , Mridula S , Mohanan P 
Published: January 2014

ABSTRACTAn electrically small, broadband‐modified, truncated ground metamaterial EZ antenna is presented. This, a modified EZ antenna system, achieves a larger bandwidth of the order of 650 MHz by adjusting the metamaterial‐inspired meandered ground element fed by a top loaded monopole. The design is devoid of the large ground planes and the external parasitic elements used in conventional designs for achieving proper impedance matching characteristics. The antenna requires a small foot print of λg/5 × λg/10, where λg is the guided wavelength corresponding to the lowest frequency of operation, when printed on a substrate of dielectric constant 4.4 and thickness 1.6 mm. The antenna offers a 2:1 VSWR bandwidth from 750 MHz to 1.4 GHz, which covers CDMA, GSM, and ISM bands. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:610–613, 2014
New compact E‐plane microstrip‐to‐waveguide transition with slotted ground plane coupling
Authors: Gholami Mehrad , Yagoub M. C. E. 
Published: January 2014

ABSTRACTIn this article, a new compact microstrip‐to‐waveguide transition is presented. With 10% bandwidth for 20‐dB return loss and 0.2‐dB insertion loss, the proposed X‐ and Ku‐band designs are insensitive to manufacturing tolerances. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:615–619, 2014
Planar monopole antennas for digital TV, design, and measurement
Authors: Perotoni Marcelo B. , Vieira Marcos S. , Barbin Silvio E. , Garcia Paulo A. 
Published: January 2014

AbstractThis article covers the design and evaluation of two wideband, low‐cost elliptical planar monopole antennas designed for the Brazilian Digital TV System. The antennas had their performance evaluated in terms of their scattering parameters as well as in field measurements in a densely urbanized area, using a spectrum analyzer. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:582–586, 2014
Design of double frequency selective surfaces using multiresonant ring patch elements of four different sizes for four bands
Authors: Park Jae H. , Choi Hak K. 
Published: January 2014

ABSTRACTIn this article, a double layer frequency selective surface (DFSS) composed of ring patch elements of four different sizes is proposed, to obtain angle and polarization insensitivity, and a broad bandwidth. The multiresonant elements with different sizes are then arranged into a unit cell that is to be repeated periodically. The proposed DFSS reflects the X and K‐band signals, while allowing the C‐ and Ku‐band signals to pass through. In this design, a four‐band FSS (including band‐stop FSS and band‐pass FSS) with a broad bandwidth is obtained, by adjusting the sizes of the rings, and thickness of the air foam between the FSS layers. Experimental verifications are carried out. The computed results agree well with the measured ones. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:547–552, 2014
Design of dual‐passband filter using dual mode semicircular dielectric resonators
Authors: Dwivedi Prashant Kishor , Awasthi Seema , Biswas Animesh , Srivastava Kumar Vaibhav 
Published: January 2014

AbstractThis article demonstrates a dual‐passband filter based on dual‐mode dielectric resonators (DR). In communication systems, dual‐band filters find vital applications as to reduce the size of the system which further decreases the cost of the system. The dual‐band filters can be designed using dual‐mode DR which are realized using semicircular DR. The designed filter introduces a very low level of complexity by reducing the number of coupling to be handled to realize the filter. The dual‐mode concept has been incorporated by using the concept of semicircular DR. Also, the control mechanisms have been provided to work independently with each couplings. The designed filter uses the concept of orthogonal modes in the DR which are further utilized to produce the two passbands. This dual‐band filter is operating at center frequencies 5.28/5.58 GHz with almost 1% bandwidth in each band. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:542–547, 2014
Comparison of network analysis methods for computing complex propagation coefficients of dispersive transmission lines
Authors: Remillard Stephen K. , Ploch Caitlin , McLellan Kyle , Bunnell V. Andrew 
Published: January 2014

ABSTRACTTransmission lines of various degrees of dispersion are often designed and fabricated for use in high speed circuits and in metamaterials. The quick generation of dispersion diagrams and attenuation coefficient curves can be made from S‐parameter measurements, with S21 alone being sufficient for generating dispersion diagrams. S21 is also sufficient to accurately measure the attenuation coefficient, group velocity, phase velocity, and effective index of refraction of highly dispersive transmission lines. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:758–761, 2014
Ultrawideband notch‐band power divider with bandpass response using defect microstrip structure
Authors: Song Kaijun , Ren Xue , Chen Fulong , Fan Yong 
Published: January 2014

AbstractA novel ultrawideband (UWB) notch‐band power divider with bandpass response has been presented. The short‐circuited coupled lines and open/short‐circuited slotline are introduced to construct this power divider. A resistor, R, is located across the slotline to improve the isolation between the output ports. The defected microstrip structure has been embedded to the UWB power divider and the notch band within the UWB passband is implemented. The central frequency and bandwidth of the notch band can be controlled by tuning the structural parameters. The presented power divider has been developed and measured. The measured notch band is located at 5.9 GHz with an attenuation of around 22 dB. The measured results show reasonable agreement with the predicted ones. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:711–715, 2014
Pulse injection for real‐time monitoring of tunable high‐Q filters
Authors: Khater M. Abu , Peroulis D. 
Published: January 2014

ABSTRACTA new measurement technique for monitoring the frequency of high‐Q microwave tunable filters in real time is presented in this work. Relying on the natural response of a cavity resonator, the technique provides the operating frequency information in a binary digital format, making it easy to read and process. The presented methodology is experimentally demonstrated on band‐stop filters, implemented by highly loaded substrate‐integrated cavities in the 1.5 GHz range. Measured results show that the changes in frequency as small as 2–20 MHz (0.13–1.3%) can be detected for a tunable cavity filter (1.42–1.65 GHz) within 1 ms, based on commercial‐off‐the‐shelf components. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:761–764, 2014
Millimeter‐wave miniaturized couplers integrated on BiCMOS technology
Authors: Titz Diane , Ferrero Fabien , Pilard Romain , Jan Sébastien , Gianesello Frédéric , Luxey Cyril , Gloria Daniel , Jacquemod Gilles 
Published: January 2014

ABSTRACTIn this article, we present a new wideband hybrid coupler for millimeter‐wave applications realized in the BiCMOS9MW 130‐nm process from STMicroelectronics. The fabrication of two slightly different couplers demonstrates the wideband performance associated with miniaturized size, thanks to the use of meandered transmission lines and lumped capacitors. The best coupler provides a −10‐dB matching bandwidth of 42% with an insertion loss of 0.6 dB and a phase shift of 88° at 60 GHz. The amplitude imbalance and the phase imbalance stay, respectively, within ±1 dB and ±5° over 27 and 36%. These state‐of‐the‐art results are compared to recently published results obtained with comparable hybrid couplers. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:587–590, 2014
Monotone combined edge finite volume–finite element scheme for Anisotropic Keller–Segel model
Authors: Chamoun Georges , Saad Mazen , Talhouk Raafat 
Published: January 2014

AbstractIn this article, a new numerical scheme for a degenerate Keller–Segel model with heterogeneous anisotropic tensors is treated. It is well‐known that standard finite volume scheme not permit to handle anisotropic diffusion without any restrictions on meshes. Therefore, a combined finite volume‐nonconforming finite element scheme is introduced, developed, and studied. The unknowns of this scheme are the values at the center of cell edges. Convergence of the approximate solution to the continuous solution is proved only supposing the shape regularity condition for the primal mesh. This scheme ensures the validity of the discrete maximum principle under the classical condition that all transmissibilities coefficients are positive. Therefore, a nonlinear technique is presented, as a correction of the diffusive flux, to provide a monotone scheme for general tensors. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1030–1065, 2014
The second‐order upwind finite difference fractional steps method for moving boundary value problem of oil‐water percolation
Authors: Yirang Yuan , Changfeng Li , Tongjun Sun 
Published: January 2014

AbstractThe research of the three‐dimensional (3D) compressible miscible (oil and water) displacement problem with moving boundary values is of great value to the history of oil‐gas transport and accumulation in basin evolution, as well as to the rational evaluation in prospecting and exploiting oil‐gas resources, and numerical simulation of seawater intrusion. The mathematical model can be described as a 3D‐coupled system of nonlinear partial differential equations with moving boundary values. For a generic case of 3D‐bounded region, a kind of second‐order upwind finite difference fractional steps schemes applicable to parallel arithmetic is put forward. Some techniques, such as the change of variables, calculus of variations, and the theory of a priori estimates, are adopted. Optimal order estimates in l2 norm are derived for the errors in approximate solutions. The research is important both theoretically and practically for model analysis in the field, for model numerical method and for software development. Thus, the well‐known problem has been solved.Copyright © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 30: 1103–1129, 2014
‘Join us on our journey’: exploring the experiences of children and young people with type 1 diabetes and their parents
Authors: Kime Nicky 
Published: January 2014

AbstractThis paper focuses on children and young people with type 1 diabetes and on their parents, and their experiences of diabetes care provision.Nine acute hospitals in the Yorkshire and the Humber region, UK, were recruited to participate in a qualitative research study. Children and young people with type 1 diabetes, aged 6–25, and their parents (approximately 250 participants), took part in talking groups to find out about their experiences of diabetes care provision.Findings show that there are key areas for improvement in the future diabetes care provision for children and young people, including communication and support, schools, structured education and transition. These have important implications for practice and service redesign.This study is thought to be the first of its kind to consult with children, young people and parents to find out about their experiences of type 1 diabetes care provision. The research findings add to the current evidence base by highlighting the disparities in care, the urgent need for change in the way services are delivered and the involvement of service users in this process. Copyright © 2014 John Wiley & Sons.
Hypoglycaemia in inpatients with diabetes on nasogastric feeding
Authors: Vindedzis Sally A , Marsh Beryl , Sherriff Jill L , Stanton Kim G 
Published: January 2014

AbstractHypoglycaemia in patients with diabetes on nasogastric feeding is both potentially damaging and under‐researched. We retrospectively reviewed 50 such inpatients to determine factors influencing hypoglycaemia. Our results showed 10.9% patient‐days with ≥1 hypoglycaemic episode and 3.5% total blood glucose values <3.5mmol/L. There was an association between sulphonylurea treatment and increased and extended hypoglycaemia. Reducing diabetes treatment post‐hypoglycaemia was associated with reduced subsequent hypoglycaemia but not increased hyperglycaemia.This study supports optimal blood glucose monitoring, insulin treatment and judicious medication reduction post‐hypoglycaemia. Copyright © 2014 John Wiley & Sons.
Critical limb ischaemia: an update for the generalist
Authors: Chikkaveerappa Krishnamurthy , Smout Jonathan , Scurr James RH , Benbow Susan J 
Published: January 2014

AbstractCritical limb ischaemia (CLI) occurs in those people with severely impaired peripheral circulation which can threaten the limb if not recognised or managed appropriately. It is more common in those with diabetes and is associated with poorer outcomes. Importantly, CLI is also a marker of associated cardiovascular disease.This paper describes how to recognise CLI, whether with or without tissue loss in the foot (ulceration and/or gangrene), and explains the importance of rapid and appropriate referral to a foot multidisciplinary team as part of an integrated pathway of care.In addition, it reviews the further clinical assessment of the person, and discusses the various more detailed investigations available for CLI.Finally, the treatment options available for the management of the individual with CLI are presented. Copyright © 2014 John Wiley & Sons.