bluuebunny/crossref_metadata_2025_split huggingface dataset:
Empirical study of stirring conditions on emulating rayleigh fading channels in a reverberation chamber
Authors: Nguyen Tien Manh , Kwon Jong Hwa , Chung Jae‐Young 
Published: May 2017

AbstractAn empirical study was performed to understand the relationship of stirring conditions on emulating Rayleigh fading channel inside of a reverberation chamber. The latter has dimensions of 1.8 m × 2.4 m × 1.6 m and equipped with 3 stirrers for rapid over‐the‐air testing of mobile communication devices. The stirrers were selectively turned on and off, and then the generated Rayleigh fading channel was compared with the ideal one by calculating the mean‐squared error. The results indicate that the Rayleigh fading channel inside the chamber is mostly affected by the stirrer close to the transmitting antenna. It was also demonstrated that turning on all the 3 stirrers further reduces the build‐up time of a Rayleigh fading channel, resulting in faster over‐the‐air testing capability.
Wideband slotted substrate integrated waveguide cavity‐backed antenna for Ku – band application
Authors: Kumar Arvind , Raghavan Singaravelu 
Published: May 2017

AbstractIn this article, a wideband substrate integrated waveguide (SIW) cavity‐backed antenna with multi‐resonance slots for
band application is presented and experimentally investigated in terms of antenna performances including S‐parameter, optimized parameter values, gain, and radiation pattern. With the proper placement of multi‐resonant slots on the backside of the cavity, the hybrid modes are generate in the frequency band of interest. These modes can be tuned by varying the slot parameters which result the merging of different resonant frequencies, therefore the simulated impedance bandwidth is substantially enhanced to 1.46 GHz, ranging from 12.7 to 14.16 GHz with a gain of 6.0 to 8.0 dBi. The measured result showing the fractional bandwidth of the proposed antenna is 11.8% and 11% achieved at the resonant frequencies of 13 and 14 GHz, respectively. Moreover, the antenna has the features of simple‐single layer structure, resonant frequency flexibility with multi‐resonance characteristics over a wide impedance bandwidth.
Multi‐section branch‐line couplers for crossover application
Authors: Yeo S. P. , Deng N. 
Published: May 2017

AbstractOther researchers have already designed 1‐, 2‐, 3‐, and 4‐section versions of the branch‐line coupler for crossover application. The focus of this article is on the 5‐, 6‐, and 7‐section versions. Laboratory tests show that the resulting crossovers have bandwidths of 49%, 54%, and 59% respectively.
Wideband bandstop filter using spurline and symmetric coupled open stubs
Authors: Lee Hyun‐Seung , Lim Jeong‐Taek , Jung Bang‐Chul , Woo Jong‐Myung , Kim Choul‐Young 
Published: May 2017

AbstractIn this article, we propose a structure that can extend the stopband of the bandstop filter (BSF). The bandwidth of the BSF can be extended by symmetrically combining the BSFs that electrically couple the ends of two open stubs located in parallel on a single microstrip transmission line containing a spurline. The bandwidth of the stopband of the BSF proposed in this article is increased to 3.5 GHz. We confirm that when compared to parallel open stubs without spurline filters, the stopband bandwidth is extended by approximately 289% (rejection depth: −20 dB).
Design of a novel compact microstrip diplexer with low insertion loss
Authors: Rezaei A. , Noori L. , Mohammadi H. 
Published: May 2017

AbstractIn this article, a microstrip diplexer is implemented based on a novel combination of the coupled lines and spiral structures in order to reduce the circuit size as well as insertion losses. This diplexer with an elliptic function frequency response operates at 2.4/2.79 GHz for wireless applications. Several transmission zeros on the both sides of two passbands are realized, which improve the selectivity. A theory method is presented that helps to miniaturization, control the resonance frequency, improve the insertion loss, and external quality factor simultaneously. The proposed diplexer has a compact size of 0.3λg × 0.25λg with low insertion losses of 0.18/0.39 dB at 2.4/2.79 GHz. The isolation between the two channels (S23) is better than 20.5 dB from DC up to 6 GHz. The designed diplexer is fabricated and measured. There is a good agreement between the simulated and measured results.
A wideband common‐gate CMOSLNA employing complementary MGTR technique
Authors: Guo Benqing , Chen Jun 
Published: May 2017

AbstractA wideband capacitor cross‐coupled common‐gate low‐noise amplifier (CGLNA) featured with high gain, low noise, and enhanced linearity is proposed. The linearity is enhanced by complementary multi‐gated transistor (CMGTR) technique. The bulk voltage and scaling size of auxiliary transistors are tuned to shift the distortion coefficients, compensating the nonlinearity of main transistors. In addition, the current reuse by stacked PMOS/NMOS configuration reduces power consumption while guaranteeing the input matching. A prototype is implemented in a 0.18 μm RF CMOS process. The measurement shows a maximal voltage gain of 19.5 dB, an average noise figure (NF) of 2.1 dB, and an input‐referred third‐order intercept point (IIP3) of 8.3–10 dBm over a 3 dB bandwidth of 0.2–1.6 GHz, respectively. It consumes only 3.5 mA from a 2.2 V supply.
Dual‐band balun with high isolation and flexible implementation based on three‐section pi‐shaped coupled lines
Authors: Yao Lidan , Wu Yongle , Liu Yuanan 
Published: May 2017

AbstractA novel planar dual‐band balun with high isolation and flexible implementation is proposed in this letter. Based on the design of a single‐band branch‐line balun, the ideal all‐port matching and output isolation are fulfilled. To achieve the dual‐band operation, innovative structures consisting of three‐section Pi‐shaped coupled lines in place of conventional branch lines with arbitrary impedances and phases are exploited. Moreover, expedient implementations can be regulated according to practical requirements while maintaining identical performance. Analytical closed‐form equations are obtained by even‐odd mode method and ABCD matrix. Analyses concerning the available frequency ratio are provided as well. For verification, a prototype working at 1.74 and 4.91 GHz is designed and fabricated. Both the simulation and measurement exhibit excellent properties and agree well with each other.
Spectroscopy of a Nd:YVO4 diode pumped solid state laser
Authors: Öztürk Oğuzhan Mete , Bayer Mustafa Mert , Anwar Muhammad Sohail , Zakwan Muhammad , Serpengüzel Ali 
Published: May 2017

AbstractThe 1 064 nm lasing, and 1 074 nm, and 1 084 nm luminescence are observed in a Nd:YVO4 DPSSL along with their corresponding SHG. Fundamental transitions are analyzed in terms of Stark effect. The relative intensity of the 1 064 nm laser line is an order of magnitude bigger than the luminescence lines.
SRR loaded CPW‐fed multiple band rose flower‐shaped fractal antenna
Authors: Elavarasi C. , Shanmuganantham T. 
Published: May 2017

AbstractIn this article, a compact coplanar waveguide (CPW) faded rose flower shaped fractal antenna is presented. The proposed design consists of a rose patch (top) and a split ring resonator loaded beneath the FR4, which are accountable for achieving multiple band characteristics, smallness, and fine impedance matching. The SRR rose antenna with a compacted dimension of 12 × 12 × 1.6 mm3 is fabricated and tested. The testing results show that the design proposed, having −10 dB for 1.031, 4.591, 8.284, 13.41, and 17.17 GHz, respectively, covers WLAN/IEEE 802.16/Wi‐MAX/ITU bands. It has fine radiation characteristics for both E field and H field in all the preferred operational bands and generates superior performances compared to the existing designed antenna in the reviews. The loaded rose fractal SRR structure recital is validated through negative permeability extraction and different parametric studies.
A designing method for band‐reject filter with high selectivity and tunable bandwidth
Authors: Liu Yu , Mu Chong , Xu Fang , Wang Zongjie , Li Yuenan 
Published: May 2017

AbstractHigh selectivity band‐reject filters are usually demanded in applications such as removing QAM signals of digital cable TV network and removing interference signals in communication systems. In this letter, a filter design method which employ discontinuous meandered transmission line and isolated board is proposed. The experimental results show that the transient bandwidth (between −3 and −20 dB) of our filters is less than 1 MHz. Besides, the rejecting bandwidth of our filters can be tuned to fulfill the requirements of different applications.
Electron driven mobility model by light on the stacked metal–dielectric interfaces
Authors: Pornsuwancharoen N. , Youplao Pichai , Amiri I.S. , Ali Jalil , Yupapin Preecha 
Published: May 2017

AbstractAn electron mobility enhancement is the very important phenomenon of an electron in the electronic device, where the high electronic device performance has the good electron mobility, which is obtained by the overall electron drift velocity in the electronic material driven potential difference. The increase in electron mobility by the injected high group velocity pulse is proposed in this article. By using light pulse input into the nonlinear microring resonator, light pulse group velocity can be tuned and increased, from which the required output group velocity can be obtained, which can be used to drive electron within the plasmonic waveguide, where eventually, the relative electron mobility can be obtained, the increasing in the electron mobility after adding up by the driven optical fields can be connected to the external electronic devices and circuits, which can be useful for many applications.
Investigation of a notched UWB antenna with opening and shorting resonators
Authors: Gao Guoping , Hu Bin , Yang Chen , Wang Shaofei 
Published: May 2017

AbstractIn this article, a planar ring monopole UWB antenna with two kinds of resonators are presented and investigated. The half wavelength opening resonator and quarter wavelength shorting resonator are coupled with the feed line capacitive to obtain notched characteristic. The contrast of current distribution demonstrates this novel method, and experimental results show that the proposed antennas meet the requirement of ultra‐wide bandwidth (3.1–10.6 GHz), while avoiding the interference from WLAN band. Some important models and parameters, such as the transmission line model, equivalent circuit model, VSWR, radiation pattern antenna gain, and transfer function are also studied to evaluate notched characteristics.
A compact sixteenth‐mode substrate integrated waveguide bandpass filter with improved out‐of‐band performance
Authors: Azad Amit Ranjan , Mohan Akhilesh 
Published: May 2017

AbstractThis article presents a compact sixteenth‐mode substrate integrated waveguide (SMSIW) bandpass filter operating at fundamental mode TM01. The filter size is reduced by introducing SMSIW circular cavity. It occupies only 6.25% of the conventional substrate integrated waveguide (SIW) circular cavity with same resonant frequency. The higher‐order mode TM02 of the circular cavity is suppressed by etching two slots on the ground plane to improve out‐of‐band performance. Measured results show that an out‐of‐band rejection better than 18 dB is obtained from 2.5 GHz to 8 GHz. The in‐band and out‐of‐band performance obtained from simulation and measurement are presented and they are in good agreement. The filter exhibits good stopband performance and compact size.
Design of a C‐band miniaturized rectifying circuit with a multilayer structure
Authors: Feng Xiaoping , Huang Kama , Liu Yilin 
Published: May 2017

AbstractThis article proposes a novel concept for constructing a microwave (MW) rectifying circuit by using a multilayer structure, aiming at reducing physical dimensions. Specifically, an embedded via‐hole with connection of conductor layers in the multilayer structure is designed. A full‐wave electromagnetic analysis is carried out to study the impacts of various via‐hole design parameters. Then, a C‐band rectifying circuit based on HSMS‐286C Schottky diode is fabricated with the proposed multilayer structure for demonstration. The maximum MW‐DC conversion efficiency of 61% has been measured. In comparison with the counterpart, namely a conventional microstrip rectifying circuit, the proposed multilayer circuit shows a great reduction of physical dimensions and a very similar efficiency, which validates that the proposed circuit can reduce physical dimensions significantly without sacrificing the MW‐DC conversion efficiency.
Compact power divider with improved isolation and bandpass response
Authors: He Zhaosheng , Jiang You Chang , Leng Supeng , Li Xiang 
Published: May 2017

AbstractThis article presents a compact power divider with band‐pass response and improved isolation by using substrate integrated waveguide (SIW) and defected ground structure (DGS) techniques. The band‐pass response is realized by combining the high‐pass characteristic of SIW and low‐pass feature of DGS. In order to achieve improved isolation performance, a slot which is terminated by four resistors is etched on the top plane of the SIW to balance the three input/output ports. The size of the proposed power divider is relatively small because of the slow‐wave characteristic of DGS. To verify the proposed concept, a prototype power divider with equal power division is fabricated and measured. Measured results show that it has a 3‐dB pass‐band from 8 GHz to 10 GHz and the isolation is higher than 20 dB within the pass‐band.
A novel dual polarized waveguide fed circular patch antenna for Ku band applications
Authors: Kumar P. , Masa‐Campos José Luis 
Published: May 2017

AbstractThis article presents the design of a novel dual polarized waveguide fed circular microstrip patch antenna for Ku band applications. The circular microstrip patch is fed by using a square waveguide and a cross slot. The cross slot consists two orthogonal slots for coupling the energy associated with two orthogonal modes propagated in the square waveguide, i.e. TE10 and TE01 mode in order to achieve dual polarization. The orthomode transducer is designed for the frequency range of interest in order to separate and combine two orthogonal modes and to connect with two standard WR‐51 rectangular waveguides. The design is optimized using the electromagnetic software CST Microwave Studio and the structure with optimized dimensions is fabricated and measured. The measured along with simulated antenna parameters are presented. The designed and developed dual polarized waveguide fed circular patch antenna can be used for Ku band applications.
Transmission characteristics of a two dimensional antiscatter grid prototype for CBCT
Authors: Altunbas Cem , Kavanagh Brian , Alexeev Timur , Miften Moyed 
Published: May 2017

AimHigh fraction of scattered radiation in cone‐beam CT (CBCT) imaging degrades CT number accuracy and visualization of low contrast objects. To suppress scatter in CBCT projections, we developed a focused, two‐dimensional antiscatter grid (2DASG) prototype. In this work, we report on the primary and scatter transmission characteristics of the 2DASG prototype aimed for linac mounted, offset detector geometry CBCT systems in radiation therapy, and compared its performance to a conventional one‐dimensional ASG (1DASG).MethodsThe 2DASG is an array of through‐holes separated by 0.1 mm septa that was fabricated from tungsten using additive manufacturing techniques. Through‐holes’ focusing geometry was designed for offset detector CBCT in Varian TrueBeam system. Two types of ASGs were evaluated: (a) a conventional 1DASG with a grid ratio of 10, (b) the 2DASG prototype with a grid ratio of 8.2. To assess the scatter suppression performance of both ASGs, Scatter‐to‐primary ratio (SPR) and scatter transmission fraction (Ts) were measured using the beam stop method. Scatter and primary intensities were modulated by varying the phantom thickness between 10 and 40 cm. Additionally, the effect of air gap and bow tie (BT) filter on SPR and Ts were evaluated. Average primary transmission fraction (TP) and pixel specific primary transmission were also measured for both ASGs. To assess the effect of transmission characteristics on projection image signal‐to‐noise ratio (SNR), SNR improvement factor was calculated. Improvement in contrast to noise ratio (CNR) was demonstrated using a low contrast object.ResultsIn comparison to 1DASG, 2DASG reduced SPRs by a factor of 3 to 6 across the range of phantom setups investigated. Ts values for 1D and 2DASGs were in the range of 21 to 29%, and 5 to 14% respectively. 2DASG continued to provide lower SPR and Ts at increased air gap and with BT filter. Tp of 1D and 2DASGs were 70.6% and 84.7% respectively. Due to the septal shadow of the 2DASG, its pixel specific primary transmission values varied between 32.5% and 99.1%. With respect to 1DASG, 2DASG provided up to factor of 1.7 more improvement in SNR across the SPR range investigated. Moreover, 2DASG provided improved visualization of low contrast objects with respect to 1DASG and NOASG setups.ConclusionsWhen compared to a conventional 1DASG, 2DASG prototype provided noticeably lower SPR and Ts values, indicating its superior scatter suppression performance. 2DASG also provided 19% higher average primary transmission that was attributed to the absence of interseptal spacers and optimized grid geometry. Our results indicate that the combined effect of lower scatter and higher primary transmission provided by 2DASG may potentially translate into more accurate CT numbers and improved contrast resolution in CBCT images.
Technical Note: System for evaluating local hypothermia as a radioprotector of the rectum in a small animal model
Authors: Hrycushko Brian A. , Bing Chenchen , Futch Cecil , Wodzak Michelle , Stojadinovic Strahinja , Medin Paul M. , Chopra Rajiv 
Published: May 2017

PurposeThe protective effects of induced or even accidental hypothermia on the human body are widespread with several medical uses currently under active research. In vitro experiments using human cell lines have shown hypothermia provides a radioprotective effect that becomes more pronounced at large, single‐fraction doses common to stereotactic body radiotherapy (SBRT) and stereotactic radiosurgery (SRS) treatments. This work describes the development of a system to evaluate local hypothermia for a radioprotective effect of the rat rectum during a large dose of radiation relevant to prostate SBRT. This includes the evaluation of a 3D‐printed small animal rectal cooling device and the integration with a small animal irradiator.MethodsA 3‐cm long, dual‐lumen rectal temperature control apparatus (RTCA) was designed in SOLIDWORKS CAD for 3D printing. The RTCA was capable of recirculating flow in a device small enough for insertion into the rat rectum, with a metal support rod for strength as well as visibility during radiation treatment planning. The outer walls of the RTCA comprised of thin heat shrink plastic, achieving efficient heat transfer into adjacent tissues. Following leak‐proof testing, fiber optic temperature probes were used to evaluate the temperature over time when placed adjacent to the cooling device within the rat rectum. MRI thermometry characterized the relative temperature distribution in concentric ROIs surrounding the probe. Integration with an image‐guided small animal irradiator and associated treatment planning system included evaluation for imaging artifacts and effect of brass tubing on dose calculation.ResultsThe rectal temperature adjacent to the cooling device decreased from body temperature to 15°C within 10–20 min from device insertion and was maintained at 15 ± 3°C during active cooling for the evaluated time of one hour. MR thermometry revealed a steep temperature gradient with increasing distance from the cooling device with the desired temperature range maintained within the surrounding few millimeters.ConclusionsA 3D‐printed rectal cooling device was fabricated for the purpose of inducing local hypothermia in the rat rectum. The RTCA was simply integrated with an image‐guided small animal irradiator and Monte Carlo‐based treatment planning system to facilitate an in vivo investigation of the radioprotective effect of hypothermia for late rectal toxicity following a single large dose of radiation.
Error modeling for surrogates of dynamical systems using machine learning
Authors: Trehan Sumeet , Carlberg Kevin T. , Durlofsky Louis J. 
Published: May 2017

SummaryA machine learning–based framework for modeling the error introduced by surrogate models of parameterized dynamical systems is proposed. The framework entails the use of high‐dimensional regression techniques (eg, random forests, and LASSO) to map a large set of inexpensively computed “error indicators” (ie, features) produced by the surrogate model at a given time instance to a prediction of the surrogate‐model error in a quantity of interest (QoI). This eliminates the need for the user to hand‐select a small number of informative features. The methodology requires a training set of parameter instances at which the time‐dependent surrogate‐model error is computed by simulating both the high‐fidelity and surrogate models. Using these training data, the method first determines regression‐model locality (via classification or clustering) and subsequently constructs a “local” regression model to predict the time‐instantaneous error within each identified region of feature space. We consider 2 uses for the resulting error model: (1) as a correction to the surrogate‐model QoI prediction at each time instance and (2) as a way to statistically model arbitrary functions of the time‐dependent surrogate‐model error (eg, time‐integrated errors). We apply the proposed framework to model errors in reduced‐order models of nonlinear oil‐water subsurface flow simulations, with time‐varying well‐control (bottom‐hole pressure) parameters. The reduced‐order models used in this work entail application of trajectory piecewise linearization in conjunction with proper orthogonal decomposition. When the first use of the method is considered, numerical experiments demonstrate consistent improvement in accuracy in the time‐instantaneous QoI prediction relative to the original surrogate model, across a large number of test cases. When the second use is considered, results show that the proposed method provides accurate statistical predictions of the time‐ and well‐averaged errors.
A qualitative study of women's experiences of living with COPD
Authors: Steindal Simen A. , Österlind Jane , Halvorsen Kristin , Schjelderup Therese , Kive Ellen , Sørbye Liv Wergeland , Dihle Alfhild 
Published: May 2017

AbstractAimTo explore women's experiences of living with chronic obstructive pulmonary disease (COPD) at home.DesignAn explorative and descriptive qualitative design.MethodsA consecutive sample of nine women with COPD living at home. Data were collected in 2014 using semi‐structured interviews and analysed using a qualitative content analysis.ResultsThree main themes were identified: having a good life with COPD despite limitations; predictability and confidence in getting help; and the struggle to achieve a balance between insight and compliance with management of COPD. These women experienced limitations related to the traditional female role and felt unable to fulfil their own expectations. They experienced a good life despite limitations arising from adaptation and coping strategies. To feel safe, they needed to feel confident that they would receive the necessary help in case of exacerbation of their disease. To enhance compliance with COPD management, the women wanted education that provided specific suggestions.