bluuebunny/crossref_metadata_2025_split huggingface dataset:
Viability, Adhesion and Differentiated Phenotype of Articular Chondrocytes on Degradable Polymers and Electro‐Spun Structures Thereof
Authors: Schneider Tobias , Kohl Benjamin , Sauter Tilman , Becker Tino , Kratz Karl , Schossig Michael , Hiebl Bernhard , Jung Friedrich , Lendlein Andreas , Ertel Wolfgang , Schulze‐Tanzil Gundula 
Published: December 2011

AbstractDegradable polymers are essential to enable biomaterial‐based regenerative therapies, particularly, in articular cartilage defect healing, which remains a major clinical challenge. The aim of this study was to investigate the effect of two degradable polymers (as a film or scaffold) on primary articular chondrocytes vitality, adherence, differentiated phenotype and morphology. Films and electro‐spun scaffolds were prepared from degradable poly(ether)ester urethane (PDC), which was synthesized via co‐condensation of poly(p‐dioxanone)diol and poly(ε‐caprolactone)diol with an aliphatic diisocyanate and poly(p‐dioxanone) (PPDO). The thermal and mechanical properties and the surface roughness of the films and scaffolds were examined by differential scanning calorimetry, dynamic mechanical thermal analysis, tensile tests and optical profilometry. Primary porcine articular chondrocytes were seeded on the polymers and analysed for viability, ultrastructure (scanning electron microscopy) and immunolabelled for type II collagen. All films and scaffolds exhibited a low endotoxin load < 0.06 EU/ml and only moderate cytotoxic effects when tested with L929 cells. The results of the seeding experiments revealed that survival and adhesion of chondrocytes depended strongly on seeding density. Vital chondrocytes could be detected on both PPDO and PDC films and scaffolds. They produced the cartilage‐specific protein type II collagen indicating differentiated functions. However, they exhibited a mixed morphology on the films and a more flattened cell shape on the scaffolds. The cell/biomaterial interaction in the PPDO scaffolds or films was more intense compared to that in PDC topologies.The polymer topology influences chondrocytes phenotype, whereby the scaffolds permitted a more continuous cell growth compared with the films.
Highly Flexible Poly(ethyl‐2‐cyanoacrylate) Based Materials Obtained by Incorporation of Oligo(ethylene glycol)diglycidylether
Authors: Tripodo Giuseppe , Wischke Christian , Lendlein Andreas 
Published: December 2011

AbstractPoly(ethyl‐2‐cyanoacrylate) (PECA) is a polymer with potential medical or technical applications, which are limited due to its high brittleness. In this work, the capability of different ethylene or propylene glycol‐based oligomers to provide flexible poly(ethyl‐2‐cyanoacrylate) films upon blending is analyzed. The used oligoethers have been chosen with different end groups or lateral substituents and their effects the on macroscopic behavior of the obtained materials have been characterized. During its synthesis, in situ blending of PECA was performed with increasing quantities of oligo(ethylene glycol) diglycidyl ether providing homogeneously miscible materials with single Tg's. The Tg's decreased in a concentration dependent manner and showed negative deviation from predictions by the Fox equation, possibly due to specific intermolecular interactions. Remarkably, the mechanical properties could be tailored over a wide range with Young's moduli of 0.2 to 900 MPa, which so far has not been reported for cyanoacrylate‐based materials. Therefore, the concept of compatible blends should be further explored to establish flexible cyanoacrylate‐based materials for various technical or biomedical applications.
Novel band‐pass filters using complementary split ring resonators
Authors: La Dong‐sheng , Lu Ying‐hua 
Published: December 2011

AbstractBand‐pass filters using complementary split ring resonator (CSRR) are proposed in this article. Two‐cascaded and three‐cascaded band‐pass filters using CSRR are designed, simulated, fabricated and measured. The resonant characteristics of the cascaded band‐pass filters show their advantages of compact size, excellent pass‐band performance and high out‐band suppression. The measured results show a good agreement with the simulated results. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:449–451 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26520
Experiment of substrate integrated waveguide interconnect measurement for high speed data transmission application
Authors: Li Zhaolong , Mahani Mohammad S. , Abhari Ramesh 
Published: December 2011

AbstractSubstrate integrated waveguide (SIW) has been used as a high speed interconnect for digital applications. The output eye diagram is an important indicator for evaluating the performance of the interconnect and the design of the driver and receiver units. This article studies the effect on eye diagrams based on improved driver and receiver design for a SIW interconnect system. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2012
Broadband GaN‐ON‐Si power amplifier module with fully integrated low temperature cofired ceramic passives
Authors: Liu Rui , Schreurs Dominique , Raedt Walter De , Vanaverbeke Frederik , Mertens Robert 
Published: December 2011

AbstractThis article presents the first demonstration of a broadband GaN‐on‐Si power amplifier module integrated in a low temperature cofired ceramic (LTCC) technology.The active device of the amplifier is a low cost Si‐based AlGaN/GaN high electron mobility transistor. Both the input and the output matching circuits were implemented with fully embedded passives in an LTCC substrate. Measured results show that the prototype module can exhibit an output power of 28.9 dBm and a drain efficiency of 44% at 2.9 GHz. Drain efficiency over 40% is achieved across 2.9–3.3 GHz, together with an output return loss of better than −13 dB. The major advantage of using a system‐in‐package approach with LTCC technology is the dramatic cost reduction compared with a monolithic microwave integrated circuit and the size reduction compared with a hybrid PCB approach. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:369–372, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26522
A GPS LNA RFIC with voltage‐controlled noise and input matching
Authors: Wu Jian‐Ming , Yeh Chun‐Hung 
Published: December 2011

AbstractA low‐noise amplifier (LNA) design with a voltage‐controlled matching section using a transistor for optimal matching between noise figure (NF) and input impedance is proposed in this letter. A crucial goal for the design is to achieve low NF required in the global positioning systems with a good input matching. The proposed design is based on the cascade of a common‐gate and common‐source transistor. The gate voltage of a common‐gate transistor is used to control the real part of optimum source impedance (Zopt) approximates to 50 Ω for NF and input impedance matching. Because the design does not require inductors or capacitors for noise matching, it reduces NF and chip area substantially. The LNA is designed and implemented using WIN 0.15 μm PHEMT foundry process and has an area of 0.84 mm × 0.84 mm. The power consumption is 18 mW from a 2.5 V supply voltage. The measurement results of the proposed LNA RFIC are 2.4 dB NF, 12.6 dB gain; input‐referred 1 dB compression point (IP1dB) is −6 dBm, and input‐referred third‐order intercept point is 6.3 dBm. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:332–335, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26524
Compact inverted triangle planar monopole antenna with a modified ground plane for ultra‐wideband operation
Authors: Jung Jinwoo , Lee Hyeonjin , Lim Yeongseog 
Published: December 2011

AbstractA compact inverted triangle planar monopole antenna (10 mm × 22 mm × 1.6 mm) with a modified ground plane for ultra‐wideband operation is proposed.With an inverted triangle radiator and modified ground plane with quarter circular patches, the proposed antenna has impedance bandwidth measured at 7.51 GHz (3.1–10.61 GHz), defined by 2:1 VSWR. The group delay and phase are also measured and discussed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:503–505, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26528
Filter designs based on coupled transmission line model for double split ring resonators
Authors: Yan Lei , Tang Meng , Krozer Viktor , Zhurbenko Vitaliy , Jiang Chenhui , Johansen Tom Keinicke 
Published: December 2011

AbstractThis work presents a systematic way to design filters based on coupled transmission line model of the microstrip rectangular double split ring resonators (DSRRs). This model allows to estimate all resonance modes of DSRR and extract the quality factors of the structure for filter synthesis purpose. According to the filter specifications, the low‐pass prototype parameters are used to calculate the required coupling coefficients between coupled DSRRs. The corresponding coupling coefficients are realized by using asymmetric coupled multi‐conductors networks. The proposed filter synthesis approach is experimentally verified by comparing measured and simulated data using the developed models. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:467–471, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26529
A compact second‐order frequency selective surface with broadband response
Authors: Zhou Hang , Qu Shao‐bo , Xu Zhuo , Lin Bao‐qin , Wang Jia‐fu , Ma Hua , Bai Peng , Peng Wei‐dong 
Published: December 2011

AbstractA compact second‐order frequency selective surface (FSS) with broadband bandpass response is presented.The FSS is obtained by utilizing two arrays of patches coupled together using coupling apertures. Three‐legged load (TLL) patches and TLL complementary coupling apertures are selected and arranged in an interlaced grid to achieve a more compact structure. Such closely packed FSS has the merits of low‐profile, high selectivity, smaller periodicities, low insertion losses, stable performance for various incident angles and different polarizations. Moreover, its 3dB bandwidth reaches to 34.1% while the reflectivity in the central passband is about ‐35dB. Detailed design procedure, and measurement results of the FSS are presented and discussed in this letter. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:392–394, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26532
A simplified and higher dynamic range version of the J1…J4 method for optical phase measurements
Authors: Marçal Luiz A. P. , Higuti Ricardo T. , Kitano Cláudio 
Published: December 2011

AbstractA new and an improved version of the J1…J4 method for optical phase detection, named J1–J3 method, is described, which is more stable to phase drift and simpler for implementation than the original one. The sensor dynamic range is increased while maintaining the accuracy and the minimum detectable phase‐shift. The method is experimentally validated by using an electro‐optic intensity modulator. The agreement between theoretical and experimental results, based on the 1/f voltage noise, is demonstrated. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:387–392, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26533
GaN HEMT based high‐efficiency current‐mode class‐D amplifier using chip‐on‐board technique
Authors: Park Jun‐Chul , Yoo Chan‐Sei , Kang Wonshil , Kim Dongsu , Yook Jong‐Gwan , Lee Woo Sung 
Published: December 2011

AbstractThis article presents a high efficiency current‐mode class‐D (CMCD) amplifier using a GaN high electron mobility transistor (HEMT) for class‐S system—a digitally controlled by delta‐sigma modulation. To enhance a drain efficiency of CMCD amplifier, the chip‐on‐board (COB) technique, which can reduce the external parasitic components of the packaged transistor and allow fast switching operation at high frequencies by minimizing distortion of the pulse waveform, is adopted. A LC‐resonance circuit with adequate Q values between each transistor and output matching network controls harmonic signal by using the lumped elements to extract pure fundamental frequency of the output signal. For a high efficiency push‐pull operation of CMCD amplifier, low‐loss rat‐race baluns are integrated at input and output circuits. From the measured results for a continuous wave of 3.35 GHz, the CMCD amplifier using COB technique shows a maximum output power of 35.88 dBm and a maximum power gain of about 10 dB. Also, the proposed CMCD amplifier provides a high power‐added‐efficiency (PAE) of 63.1% and a drain efficiency of 76.3% at maximum output power. The drain efficiency is still remained over 70% in the frequency range of 200 MHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:358–362, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26536
Multiband patch antennas compatible with CMOS array detector for real‐time multi‐frequency terahertz imaging system
Authors: Park Wook‐Ki , Han Seong‐Tae 
Published: December 2011

AbstractThis letter reports a miniaturized, multiband patch antenna capable of detecting thee frequencies in conjunction with CMOS array detector element for real‐time multi‐frequency imaging in terahertz (THz)‐band.Multi‐frequency operation is desirable for THz CMOS camera design, which is achieved by using stubs and slot‐type split ring resonator on the patch antenna connected to the on‐chip CMOS detector. The proposed antenna is designed at three‐bands of 218, 338, and 400 GHz corresponding to the atmospheric transmission windows. And the performance of the multiband THz antenna is successfully demonstrated using the finite‐difference time‐domain method. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2012
M‐shape surrounded with ring patch wideband monopole printed antenna
Authors: Aghda Majid Rafiee , Kamarudin M. R. , Iddi Hashim Uledi 
Published: December 2011

AbstractIn this article, a novel shape of a ring printed antenna is presented. Antenna is designed for wideband applications. There is an M‐shape patch inside the ring, which is optimized for wideband applications. The antenna operates between 2.05 and 6.85 GHz frequency bands. The measured bandwidth is about 107.87%. The proposed antenna has fabricated and tested. It has been fabricated on 30 × 51 mm2 FR4 board. A novel shape of ground plane has been used for increasing the bandwidth and removing some ripples in the result. The return loss results have been presented based on simulation and measurement. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:482–486, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26541
A 0.6‐V high reverse‐isolation through feedback self‐cancellation for single‐stage noncascode CMOS LNA
Authors: Tran T. T. N. , Boon C. C. , Do M. A. , Yeo K. S. 
Published: December 2011

AbstractIn many designs, a low supply voltage is selected for efficient use of power. However, this often leads to low reverse‐isolation which is critical to the RF front–end circuits and particularly to the low‐noise amplifier (LNA). In this letter, a fully integrated differential low‐voltage CMOS LNA with high reverse‐isolation is presented. This LNA makes use of the single‐stage noncascode structure and the capacitive cross‐coupling (CCC) technique. The CCC technique has been utilized in many LNA designs. However, in all of the reported works using CCC, the CCC technique was mainly used to improve the noise figure (NF), not the reverse‐isolation. The poor reverse‐isolation problem in single‐stage noncascode structure has never been analyzed in the capacitive cross‐coupling cascaded low noise amplifier (CCCLNA). This work shows a novel analysis on the feedback self‐cancellation mechanism to improve the reverse‐isolation. Other analyses on input matching, gain and NF were also performed to show the feasibility of using CCC technique for the low‐voltage LNA as well as the advantages of the CCCLNA over the conventional common‐source and common‐gate (CG) LNA. The LNA consumes only 0.5 mW from 0.6 V supply voltage. It achieves a gain of 14 dB and a NF of 3.55 dB. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:374–379, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26542
Novel miniaturized and high‐isolated MIMO antenna
Authors: Liu Ying , Jiang Wen , Gong Shuxi , Jiang Lintao 
Published: December 2011

AbstractA novel miniaturized and high‐isolated multiple‐input multiple‐out (MIMO) antenna is proposed. It is very difficult to reduce the mutual coupling between the MIMO antenna elements for compact mobile handset. Three‐dimensional meander lines are used as the radiator, which miniaturizes the size of the antenna. Decoupling network is introduced to improve the isolation between the ports of the two monopoles effectively. Concavo–convex rectangle is used as its ground which improves the voltage standing wave ratio (VSWR) instead of the match circuits. The proposed antenna works at 2.4 GHz. Antenna prototype is fabricated and tested, which proves its performance. In the working band, the reflection coefficient of the proposed antenna is below −10 dB, and the isolation below −15 dB. The proposed antenna has patterns close to be omnidirectional. It can be used in various areas such as MIMO, Wi‐Fi, and Bluetooth. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:511–515, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26545
Cost‐effective wavelength division multiplexing passive optical network delivering upstream/downstream data on a single wavelength using soliton pulse
Authors: Tawade Laxman , Deosarkar Shankar 
Published: December 2011

AbstractWe propose and demonstrate wavelength division multiplexing passive optical network system delivering downstream 2.5‐Gbps data and upstream 1‐Gbps data on a single wavelength using pulse source that is mode‐locked laser generating a single pulse of “sech” shape with specified power and width, that is, soliton pulse.The optical source for downstream data and upstream data is sech pulse generator at central office and reflective semiconductor optical amplifier at each optical network unit. We also investigate analysis of backscattered optical signal for upstream data and downstream data simultaneously. Bit error rate was measured to demonstrate the proposed scheme. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:508–511, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26546
Small UWB antenna with bandstop function for wireless USB of mobile handsets
Authors: Lim Yohan , Yoon Young Joong , Jung Byungwoon 
Published: December 2011

AbstractIn this letter, a small and an internal ultra‐wideband (UWB) antenna for wireless USB of mobile handsets is proposed for UWB service in which bandstop function of 5.8‐GHz wireless local area network band is required.The ground is partially removed and the microstrip feed line is gradually tapered to obtain enhanced impedance bandwidth. λ/4 short slots for bandstop function are modified into L‐type to be accommodated in a small‐sized antenna. From the measured results, wide bandwidth of 3.15–4.75 and 7.2–10.2 GHz is achieved while 5.8 GHz is notched. Three different shapes of conventional mobile terminals are also considered for measurement. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:438–441, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26551
On the accuracy of the vector fitting approximation of a cylinder nonreflecting boundary kernel
Authors: Bavelis K. , Mias C. 
Published: December 2011

AbstractThe article considers various factors that affect the accuracy of the vector fitting approximation of the kernel function that appears in a recently presented cylindrical nonreflecting boundary condition. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 54:277–282, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26555
Comparison of a monopole and a PIFA handset antenna in the presence of the human head
Authors: Risco S. , Anguera J. , Andújar A. , Picher C. , Pajares J. 
Published: December 2011

AbstractThe great majority of wireless devices, such as handset phones, are used close to the human head. This fact modifies the antenna performance compared with a free space scenario. One of the critical aspects is that the human head absorbs power from the antenna radiation. In this sense, it is necessary to reduce such absorption not only to minimize the temperature inside the head, but also to increase the radiated power to free‐space. The performance associated to two types of handset antennas, a monopole and a planar inverted‐F antenna (PIFA) is evaluated regarding the presence of the human head. The most significant parameters (reflection coefficient, efficiency, and specific absorption rate) are measured for two different positions of the antenna (handset having the antenna close to the ear and the other when the handset is rotated 180°) as a function of the low frequency region (∼ 824—960 MHz) and high frequency region (∼1710–2170 MHz). Despite the monopole presented here occupies less space and covers more bands regarding free‐space conditions, the PIFA under analysis becomes more robust to the human head loading effect. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:454–459, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26565
Ultrawideband channel measurement and modeling for the future intra‐vehicle communications
Authors: Liu Leilei , Wang Yuanqing , Zhang Yan 
Published: December 2011

AbstractIn this article, an ultrawideband channel model within an intra‐vehicle environment is investigated.The electromagnetic wave propagation is simulated by full wave method in a three‐dimensional car structure. The channel measurement is conducted in frequency domain from 2 to 15 GHz in different scenarios. The calibration process is pointed out to ensure the accuracy in data analysis. The statistical analysis is presented using the channel impulse response calculated via inverse Fourier transform. The small scale features of the intra‐vehicle environment are then deduced. An interesting result shows that the delay spreads linearly decrease with the increased passenger number. The clustering channel model is developed based on Saleh–Valenzeula (S–V) model fitting into the vehicular environments with dense clusters and rays. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:322–326, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26568
Transmission resonant frequency and its amplitude prediction for ebg structure based on phase coherence
Authors: Ning Huansheng , Wang Jun , He Wei , Mao Lingfeng 
Published: December 2011

AbstractA new method based on phase coherence is proposed for the strengthened resonant transmission frequency and its amplitude prediction. This method has a clear physical meaning and great convenience. A microstrip electromagnetic bandgap structure is used to verify the method, and both the simulated and measured results demonstrate its validity. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:409–412, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26570