bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Structural Stability and Water Retention Characteristics Under Different Land uses of Degraded Lower Himalayas of North‐West India
Authors: Saha D. , Kukal S. S. 
Published: March 2013

AbstractThe lower Himalayan regions of north‐west India experienced a severe land‐use change in the recent past. A study was thus conducted to assess the effect of grassland, forest, agricultural and eroded land uses on soil aggregation, bulk density, pore size distribution and water retention and transmission characteristics. The soil samples were analysed for aggregate stability by shaking under water and water drop stability by using single simulated raindrop technique. The water‐stable aggregates (WSA) >2 mm were highest (17·3 per cent) in the surface layers of grassland, whereas the micro‐aggregates (WSA < 0·25 mm) were highest in eroded soils. The water drop stability followed the similar trend. It decreased with the increase in aggregate size. Being lowest in eroded soils, the soil organic carbon also showed an adverse effect of past land‐use change. The bulk density was highest in eroded lands, being significantly higher for the individual aggregates than that of the bulk soils. The macroporosity (>150 µm) of eroded soils was significantly (p < 0·05) lower than that of grassland and forest soils. The grassland soils retained the highest amount of water. Significant (p < 0·05) effects of land use, soil depth and their interaction were observed in water retention at different soil water suctions. Eroded soils had significantly (p < 0·05) lower water retention than grassland and forest soils. The saturated hydraulic conductivity and maximum water‐holding capacity of eroded soils were sufficiently lower than those of forest and grassland soils. These indicated a degradation of soil physical attributes due to the conversion of natural ecosystems to farming system and increased erosion hazards in the lower Himalayan region of north‐west India. Copyright © 2013 John Wiley & Sons, Ltd.
High absorption terahertz‐wave absorber consisting of dual‐C metamaterial structure
Authors: Jiu‐Sheng Li 
Published: March 2013

AbstractWe report a perfect absorber based on dual‐C metamaterial structure operating in the terahertz regime.The proposed structure is numerically investigated by the CST Microwave Studio. By manipulating the periodic patterned structures as well as the dielectric layer material, significantly high absorption can be obtained at specific resonance frequency. The fabricated device has been characterized using a Fourier transform infrared spectrometer. The experimental results show that the distinct absorption peak at 0.573 THz with absorption magnitudes of 0.996, which is in good agreement with the simulation. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1185–1189, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27468
Linearization of stacked‐fet RF CMOS power amplifier using diode‐integrated bias circuit
Authors: Kong Jeongwoon , Jeong Jinho 
Published: March 2013

AbstractIn this article, the linearization circuit of stacked‐FET RF CMOS power amplifier (PA) is presented. The proposed diode‐integrated bias circuit provides the increasing DC gate bias current which allows the bottom FET in the tripled‐stacked FET to saturate at a higher power compared to the conventional bias circuit. The simulation shows that the proposed bias circuit can increase a 1‐dB gain compression point of the stacked‐FET PA with a higher efficiency. It is demonstrated from the measurement of the triple‐stacked CMOS PAs with W‐CDMA input signal that the proposed diode‐integrated bias circuit can reduce the spectrum regrowth and increase the average efficiency. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1011–1014, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27472
Broadband high‐gain Fabry–Perot cavity antenna with back radiation reduction
Authors: Ju Jeongho , Choi Jae Ick 
Published: March 2013

AbstractA Fabry–Perot (FP) cavity antenna simultaneously producing a high‐gain, wide‐bandwidth, and high front‐to‐back ratio (FBR) is proposed. To reduce the back radiation, we enclosed all the openings of our antenna with folded metal walls having a length of approximately 0.2λ at a center frequency of 1.8 GHz, and to obtain a broader bandwidth and high gain, we employed a superstrate composed of double layered metal strip lines and placed over a feeder antenna. The antenna with folded metal walls compared to without folded metal walls yields a significant reduction in back radiation levels over the operating frequencies. An average suppression in back radiation of 20 dB was obtained, and a maximum gain value of 18.77 dBi has been measured over a 3 dB gain bandwidth of 24.1% (1.64–2.09 GHz). © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:975–978, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27474
Bandpass waveguide in 3D diamond‐structure EBG fabricated by stereolithography and gel casting
Authors: Chen Shibin , Li Dichen , Sun Kun , Han Haoxue 
Published: March 2013

AbstractA waveguide located in a diamond photonic crystal (PC) is presented in this article. The alumina‐based three‐dimensional electromagnetic band gap crystal has been designed, optimized, and fabricated by the stereolithography combined with gel‐casting, which experimentally exhibited a large bandgap between 13.8 and 16.3 GHz with a relative width of 16.7%. Meanwhile, a waveguide located in such diamond structure has been designed and fabricated, which shows obvious bandpass between 13.8 and 15.5 GHz. Transmission properties of PCs waveguide will achieve their integration applications in standard microwave devices. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1145–1149, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27478
Compact circularly polarized circular microstrip tag antenna mountable on metallic surface
Authors: Kuo Shang‐Huang , Chen Horng‐Dean , Pan Shan‐Cheng , Tseng Yen‐Ming , Jheng Jing‐Lun 
Published: March 2013

AbstractA compact circularly polarized circular microstrip tag antenna designed for RFID UHF band is presented.The proposed tag antenna is excited by using microstrip‐line coupling‐feed method. By choosing the proper lengths of two short‐circuited arc microstrip lines and its coupling distance, good complex impedance matching can be obtained. Moreover, a cross slot of unequal arm lengths embedded in a circular patch is used to achieve compact circularly polarized operation. The measured 10‐dB return‐loss bandwidth of the tag antenna is 40 MHz (901–941 MHz), while the 3‐dB axial‐ratio bandwidth is 6 MHz (912–918 MHz). Further experiment shows that the tag antenna can provide a significantly increased reading range when mounted on a metallic surface. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1107–1112, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27480
In‐line one‐pump parametric amplifier with independent polarization gain: A field‐trial demonstration
Authors: Marconi Jorge D. , Fugihara Meire C. , Callegari Fulvio A. , Fragnito Hugo L. 
Published: March 2013

AbstractWe present a one‐pump parametric amplifier with polarization independent gain working as an in‐line amplifier within an experimental field‐trial optical network. The polarization independent gain is obtained by using a polarization diversity technique (PDT). Five signals modulated at 10 Gb/s were transmitted through the network, and a gain variation as low as 0.05 dB, independent of the signal polarization, was obtained. The bit‐error‐rate (BER) for the amplified signals was measured. For a BER of 10−9, a power penalty as low as 0.7 dB is shown. These measurements were compared with the identical ones obtained when the parametric amplifier with the PDT was replaced by an Erbium‐doped fiber amplifier (EDFA). The fiber optical parametric amplifier (FOPA) with the PDT presents a power penalty of 0.7 dB in relation to the value obtained with the EDFA. These results show that parametric amplifiers that use the PDT are able to reach a performance comparable to those obtained with the current technology of optical amplifiers based on rare earth doped fibers. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1104–1107, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27481
Frequency‐ and time‐domain performance of a miniature planar ultra‐wideband antenna
Authors: Guo Lu , Chen Xiaodong 
Published: March 2013

AbstractA miniature planar antenna for ultra‐wideband (UWB) applications is presented in this article. The proposed compact antenna consists of a quasi‐self‐complementary structure together with a tapered radiating slot. The optimal design of this type of antenna has been demonstrated to provide an ultrawide 10‐dB return loss bandwidth with satisfactory radiation properties. It also exhibits a fairly small dimension, 19 mm×16 mm in physical size and 0.19λ in electrical size, respectively. A parametric study is conducted to provide insights into the antenna operating mechanism. In addition, the time domain behavior of the proposed antenna is also examined. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1058–1065, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27483
A novel all‐fiber velocity interferometer with high fringe contrast
Authors: Hong Guangwei , Jia Bo , Xiao Qian , Tang Huang 
Published: March 2013

AbstractA novel all‐fiber velocity interferometer with high fringe contrast (NAFVISAR) is proposed and demonstrated. The configuration of the AFVISAR utilizes PBS to remove the unwanted non‐interfering light beams from the moving target, which can approximately double the fringe visibility constant of the system compared with Levin's structure. With shaker vibration experiment, it is shown that the NAFVISAR achieved a fringe contrast of 0.91. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1029–1031, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27484
Design and performance of an HTS wideband microstrip bandpass filter at X‐band
Authors: Shang Zhaojiang , Guo Xubo , Cao Bisong , Zhang Xiaoping , Wei Bin , Heng Yong , Song Xiaoke , Suo Guannan , Wang Jingchen , Li Qirong 
Published: March 2013

AbstractThis article presents a 10‐pole high‐temperature superconducting (HTS) wideband microstrip bandpass filter with a novel configuration and compact size.The filter at 10 GHz with a fractional bandwidth of 40% is designed and fabricated on a 32.6 mm × 6.7 mm × 0.5 mm MgO substrate with double‐sided YBCO films. The internal couplings between quarter‐wavelength resonators are realized by parallel‐coupled microstrip line (PCML) structure and capacitive open‐ended stubs. The strong external couplings required by wideband filter are realized by impedance steps and capacitive stubs. The measured results at 55 K, without any tuning, show a high performance. The insertion loss is less than 0.31 dB, the return loss is better than −14 dB, and the out‐of‐band rejection is higher than 70 dB. The overall measurements are in good agreement with the simulations. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1027–1029, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27485
An isotropy dual‐band terahertz metamaterial
Authors: Li Biao , He Lianxing , Yin Yingzeng , Guo Wanyi , Sun Xiaowei 
Published: March 2013

AbstractAn isotropy terahertz (THz) metamaterial for dual‐band operation is designed and fabricated. The proposed metamaterial is composed of periodically arranged double metallic rings, and negative permittivity is obtained in 298–388 GHz and 652–780 GHz bands. Transmission and reflection characteristics of the proposed structure are simulated using Ansoft High Frequency Structure Simulator. The designed sample is fabricated on a gallium arsenide layer, and experiments are performed in THz time‐domain spectroscopy. The experimental results agree well with the simulations. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:988–990, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27486
Crescent slot antenna for 2.4/5.2/5.8 GHz wireless local area network operations
Authors: Lin Chun‐Cheng , Huang Chih‐Yu , Wang Bo‐Chun 
Published: March 2013

AbstractA nonconcentric crescent slot antenna design for wireless local area network (WLAN) operation is proposed. The antenna has a single radiating slot for dual‐band operation and a simple feeding structure for impedance matching. It provides two 10‐dB impedance bandwidths of 115 MHz (ca. 4.7% centered at 2.45 GHz) and 1130 MHz (ca. 20.5% centered at 5.5 GHz). The nonconcentric crescent slot design covers the 2400–2484 and 5150–5825 MHz bands of WLAN operations. The return loss, radiation performance, and magnetic current distributions are studied and discussed. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1081–1085, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27491
Rectangular ring‐shaped dielectric resonator antenna for dual and wideband frequency
Authors: Khalily Mohsen , Rahim Mohamad Kamal A. , Murad Norasniza A. , Samsuri Nor Asmawati , Kishk Ahmed A. 
Published: March 2013

AbstractA new modified planar dielectric resonator antenna (DRA) is presented and investigated. The proposed DRA is excited by a microstrip feed that is extended as a probe in the proximity of the DR. On the opposite side to the probe excitation printed narrow strips directly connected to the ground plane edge are used to improve the radiation characteristics of the antenna by keeping a unidirectional broadside radiation. In addition, the short circuit strips introduce a second frequency band. Thus, a dual‐band antenna is achieved. The measured bandwidths are about 73% (2.78–5.95 GHz) for the wideband DRA as well as 8% (2.4–2.6 GHz) and 56% (3.3–5.85 GHz) for the dual‐band DRA. The minimum and maximum gain enhancements of about 0.6 and 1.2 dB from 3.5 to 6 GHz are obtained. Parametric study and measurement results are presented and discussed. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1077–1081, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27492
Broadband Schiffman phase shifter using coupled suspended lines with tuning septums
Authors: Rhee Seungyeoup 
Published: March 2013

AbstractA novel design of 90° Schiffman phase shifter using coupled suspended lines with tuning septums is presented for broadband operations.In this design, the 90° Schiffman phase shifter is realized with a high impedance ratio, which cannot be implemented using conventional coupled lines. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1036–1038, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27494
Planar monopole antenna for multiband wireless applications
Authors: Hosseini Seyed Ehsan , Attari Amir Reza , Majedi Mohammad Saeed 
Published: March 2013

AbstractIn this article, a new multiband planar monopole antenna for mobile devices application is presented. The proposed antenna operation is on the basis of using two radiation spiral strips and two slots on the ground plane. This antenna covers eight standard frequency bands including: GSM900, DCS1800, PCS1900, UMTS, WiBro, Bluetooth, WiMax, and WLAN. It occupies the area of 40 mm × 18 mm excluding the ground plane. A prototype of this antenna has been fabricated and its parameters have been measured. There is a good agreement between the measured and simulated results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:966–970, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27497
High performance microstrip transverse resonance lowpass filter
Authors: Verma Anand K. , Chaudhari Nainu P. , Kumar Ashwani 
Published: March 2013

AbstractWe report 5‐pole Butterworth transverse resonance type lowpass filter (TR‐LPF) at cut‐off frequency 2.5 GHz with sharpness of cut‐off 170 dB/GHz, at 20 dB, 30 dB, 40 dB, and 50 dB rejection bandwidth of 9.2 GHz, 7.7 GHz, 5.9 GHz, and 3.12 GHz, respectively.The depth of attenuation is 68.7 dB. The parameters could be optimized for given specification. Such high order of attenuation is achieved by 30‐pole classical Hi–Lo LPF. The attenuation can be further increased to 72 dB for a 7‐pole LPF and 94 dB for a 11‐pole LPF. In case of the 11‐pole LPF at fc=2.5 GHz, we can achieve more that 7.1 GHz rejection bandwidth at 70 dB rejection. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1149–1152, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27501
Comparative study of numerical methods used in modeling of photonic crystal fibers
Authors: Díaz‐Soriano A. , Ortiz‐Mora A. , Dengra A. 
Published: March 2013

AbstractIn this article, we present a performance comparison, in terms of accuracy and computational cost, of the numerical techniques used in the resolution of the models of photonic crystal fibers.These models allow to obtain the electromagnetic field distributions and, once known this one, the dispersion parameter and the nonlinear coefficient. In this study, we conclude that the central finite difference scheme of fourth order would be the most advantageous. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1049–1053, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27504
Novel balanced BPF design using half‐mode substrate integrated waveguide with common‐mode suppression
Authors: Ho Min‐Hua , Li Cheng‐Siou 
Published: March 2013

AbstractThe contribution of this letter is to propose a novel balanced bandpass filter (BPF) design of the half‐mode substrate integrated waveguide (HMSIW) using open‐stubs for the common‐mode (CM) suppression. The HMSIW is a half‐mode waveguide alike structure, which is composed of a substrate sided with a thru‐via array emulating the shorted side‐wall of the half‐mode waveguide. As compared with some other planar structures, such as microstrip line, coplanar waveguide, and slotline, the HMSIW possesses a relatively high quality factor and is immune of the waveguide's notorious bulkiness and high fabrication cost. The insertion losses of the proposed balanced BPF are extremely low in differential mode (DM) and the CM rejection levels are over 30 dB in the DM's passband. The thru‐via array that existed in the HMSIW is eliminated in this balanced BPF design, greatly decreasing the fabrication complexity. Prototype of the proposed balanced BPF is fabricated and measured. Agreements between measured and simulated data are observed, validating the circuit performance. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1112–1115, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27510
Direct synthesis procedure for sub‐harmonic stub band‐pass and band‐stop filters
Authors: Stander T. , Sinha S. 
Published: March 2013

AbstractA non‐iterative synthesis procedure for sub‐harmonic stub (SHS) band‐pass and band‐stop filters is presented. The method ensures better agreement between the synthesized filter response and the original prototype function than was possible previously without iterative techniques. The procedure is illustrated for two L‐band microstrip filters, with good agreement between modeled and measured responses. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:995–998, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27513
A compact CPW‐FED UWB antenna with independent dual band‐notched characteristics
Authors: Liu Xianglong , Yin Yingzeng , Liu Pingan 
Published: March 2013

AbstractIn this article, a new design of a coplanar waveguide fed (CPW‐fed) ultra‐wideband (UWB) antenna with dual band‐notched characteristics is presented. To achieve ultra‐wideband impedance matching, the tapered geometry is adopted. The two meandered split resonant slots that are etched on this antenna are to reduce the possible interferences with the band of 3.2–3.8 GHz and 5.1–5.8 GHz, which cover both WLAN and WiMAX. The upper slot (shorter in length) controls the higher band, while the lower one (longer in length) controls the lower band. Antennas with and without slots are analyzed and compared, which indicates the ability of two incorporated slots to tune the notch‐band independently. A prototype is fabricated and measured, and the good agreement between simulated and measured results manifests the effectiveness of this design. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1126–1130, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27519
A high‐performance CMOS power amplifier for 60 GHz short‐range communication systems
Authors: Chang Jing‐Ning , Lin Yo‐Sheng 
Published: March 2013

AbstractA 60 GHz power amplifier for direct‐conversion transceiver using standard 90 nm CMOS technology is reported.The power amplifier comprises three cascaded common‐source stages with inductive load and inter‐stage matching. To increase the saturated output power (Psat) and power‐added efficiency (PAE), the output stage adopts a two‐way power dividing and combining architecture. Instead of the area‐consumed Wilkinson power divider and combiner, miniature low‐loss LC power divider and combiner are used. This in turn results in further Psat and PAE enhancement. Over the 57 ∼ 64 GHz frequency band of interest, the power amplifier consumes 44.4 mW and achieves power gain (S21) of 12.04 ± 1 dB, input‐port input return loss (S11) of −6 to −9.4 dB, output‐port input return loss (S22) of −10.4 to −26.4 dB, and reverse isolation (S12) of −29.2 to −30.6 dB. At 60 GHz, the power amplifier achieves Psat of 11.4 mW and maximum PAE of 15.8%. To the authors' knowledge, this is the best PAE ever reported for a 60 GHz CMOS power amplifier. In addition, the measured output 1‐dB compression point (OP1 dB) is 6 dBm at 60 GHz. These results demonstrate that the proposed power amplifier architecture is very promising for 60‐GHz short‐range communication systems. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1155–1160, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27522
A new siw resonator excitation method and its equivalent circuit
Authors: Ladani Faezeh Tork , Jam Shahrokh , Safian Reza 
Published: March 2013

AbstractThis article presents a new method for excitation of substrate integrated waveguide (SIW) cavity resonators which is suitable for multilayer structures and provides a method for exciting SIW cavities.The structure is analyzed and its equivalent circuit is presented to give a better insight of the structure's response through circuit theory. The analytical discussion is validated by simulations using Ansoft HFSS and ADS softwares. A three‐pole narrowband SIW filter has been designed by this method of cavity coupling as one of possible applications of the presented structure. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1133–1138, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27527