bluuebunny/crossref_metadata_2025_split huggingface dataset:
On fractal FSS suitable for WLAN and WiMAX communication
Authors: Ray Arup , Kahar Manisha , Sarkar Debashree , Sarkar P. P. 
Published: April 2015

ABSTRACTMultiband properties of three different types of fractals namely Sierpinski Carpet, Koch Snowflake, and Sierpinski Gasket have been exploited. It is seen that all three fractal frequency selective surfaces (FSSs) on suitable optimization of their fractal geometry exhibit dual band properties of wireless local area network (WLAN), IEEE 802.11b standard, but at the fatal cost of large electrical size. In an attempt of making their size less, the Sierpinski Carpet and Koch Snowflake fractal looses their resonance properties partially at WLAN frequencies; however, the newly designed, modified Sierpinski Gasket FSS, marvelously exhibits stable resonance at WLAN frequencies with an additional resonance at WiMAX frequency, IEEE 802.16e standard. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1546–1550, 2015
A wideband EBG resonator antenna with an extremely small footprint area
Authors: Hashmi Raheel M. , Esselle Karu P. 
Published: April 2015

ABSTRACTAn electromagnetic band gap resonator antenna (ERA) with an extremely small footprint is presented. The proposed ERA has a peak measured gain of 15.6 dBi and an excellent measured 3dB gain‐bandwidth of 27%. The four‐layer composite superstructure used in this ERA takes the shape of a circular disc with the ground plane radius equal to that of the superstructure. Its footprint area is only 1.7λ02 at the lowest operating frequency. The average measured aperture efficiency of this ERA is nearly 90%. The side lobe levels are well below −12 dB over most of the operating bandwidth and the cross polarization levels are below −17 dB. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1531–1535, 2015
An unequal Gysel power divider based on circuit transformation
Authors: Kim Young , Sim Seok‐Hyun , Yoon Young‐Chul 
Published: April 2015

ABSTRACTThis article presents an unequal Gysel power divider (UGPD) based on circuit transformation, which is converted from a Π‐ to a T‐type circuit. The Π‐type circuit of a conventional unequal Gysel divider consists of two different value resistors and its connection transmission line. In the proposed T‐type circuit, the dummy transmission line and the other transmission line with shunt resistor at center position is connected in parallel. Theoretical analysis was performed to derive the design equations for the proposed circuit conversion. For the validation of the circuit transformation, the UGPD using a T‐type circuit at the center frequency of 2 GHz was fabricated and measured. The measured characteristics agreed well with the simulation results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1529–1531, 2015
Selectable sectoral antenna array using a quadruple feeding network for item‐level tagging in UHF RFID applications
Authors: Lee Wang‐Sang , Yu Jong‐Won 
Published: April 2015

ABSTRACTFor avoiding a dead zone where the tag cannot be detected in the ultrahigh‐frequency (UHF) radio frequency identification (RFID), a SELECTABLE SECTORAL ANTENNA ARRAY USING a QUADRUPLE FEEDING NETWORK FOR ITEM‐LEVEL TAGGING IN UHF RFID APPLICATIONS is presented. The proposed antenna array consists of a 2 × 2 circular polarized quadrifilar spiral antenna array and a quadruple feeding network for multiple beams. It generates single, dual, and quad beams with a hemispheric coverage by a beam switching, and its maximum gain and 3 dB beamwidth are approximately 7.8 dBic and 60°, respectively. Compared with the conventional antennas, the proposed antenna array provides the improved tag identification with the dead zone avoidance in the reading range. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1523–1526, 2015
Direct‐fed reduced size patch antenna using array of cSRR in the ground plane
Authors: Elsdon Michael , Yurduseven Okan 
Published: April 2015

ABSTRACTIn this article, a novel design for a reduced size microstrip patch antenna is presented and discussed. It is demonstrated that by embedding an array of complimentary split ring resonators in the ground plane, size reduction of 11.2%, together with an increased bandwidth of 202.6% can be achieved. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1526–1529, 2015
WDM‐OFDMA‐PON uplink optical transmission using bandwidth enhanced injection‐locked FP‐LD
Authors: Yang Seung‐Min , Kim Chang‐Hun , Jung Sang‐Min , Han Sang‐Kook 
Published: April 2015

ABSTRACTWe propose a scalable support WDM‐based orthogonal frequency division multiple access‐passive optical network uplink transmission system using an injection‐locked Fabry–Perot laser diode (IL‐FP‐LD). This system uses an injection‐locking technique to enhance the usable bandwidth by making stable channel states. By properly controlling the IL‐FP‐LD operation, the number of optical network units (ONU) within a wavelength can be increased, which improves the optical bandwidth efficiency for the uplink transmission. The experimental results show an enhanced modulation bandwidth of 3.5 GHz. Compared with a conventional RSOA which has a modulation bandwidth of 1.5 GHz, our scheme improves the number of ONUs that can be accommodated within a wavelength more than two times. The total discrete multitone signal received from the ONUs, with QPSK mapping on the subcarriers was 6.77 Gbps over a 23‐km standard single mode fiber transmission. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1727–1732, 2015
Low phase noise Ku‐band push–push oscillator based on compact spiral‐resonator array
Authors: Li Zhipeng , Huang Hongyun , Liu Yongzhi , Bao Jingfu 
Published: April 2015

ABSTRACTA low phase noise push–push oscillator using compact spiral resonator (SR) array is presented in this letter. The proposed SR array can provide high frequency selectivity in compact size due to its intrinsic source‐load coupling structure. In addition, the SR array acts as a phase coupling network to ensure the out of phase operation mode in two suboscillators. The proposed SR array has a very compact size of 0.17λg×0.17λg. A 14.2 GHz push–push oscillator based on this SR array has been designed and implemented. The measured phase noise is −108.35 dBc/Hz at 100 kHz offset frequency, and the suppression of fundamental frequency and the third harmonic are −23.16 dBc and −37.21 dBc, respectively. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1683–1686, 2015
Compact dual‐band bandpass filters based on a novel defected ground spiral resonator
Authors: Xiao Mi , Sun Guoliang , Xu Fang 
Published: April 2015

ABSTRACTA novel defected ground structure spiral resonator with two spiral stubs and a center stub was presented in this article. Full‐wave simulation was used to investigate the working principle of the resonator. The results show that the spiral resonator has two operating modes, so that it can produce two resonant frequencies. It is also found that it is convenient to control the two resonant frequencies by adjusting the dimensions of the two spiral stubs and the center stub. A dual‐band bandpass filter (BPF) was designed using two resonators of this type and a T‐shaped coupling node, having a bandwidth of 4.5% at 1.87 GHz and a bandwidth of 3.3% at 2.43 GHz. The measured results of the designed dual‐band BPF agree well with the simulated responses. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1636–1640, 2015
An algorithm of impairment aware routing for wavelength division multiplexed optical networks
Authors: Kaur Karamjit , Singh Hardeep 
Published: April 2015

ABSTRACTDevelopment of wavelength division multiplexing technologies and increased transparency in the networks has tremendously increased the information carrying capacity of fiber optic networks. However, these networks are affected by accumulation of optical impairments along the lightpath resulting in degradation of signal being transmitted thereby creating inadequacy to meet quality of service requirements. In this article, effort has been put in to identify different parameters affecting the signal quality. A technique to measure these parameters and their application in connection provisioning is presented. Electrical postprocessing techniques are implemented to calculate quality of link path. The algorithm designed consider the quality of lightpath for connection provisioning for each connection requirement based on first fit, best fit, and shortest path principle. The performance of designed algorithm has been verified by presenting different quality conditions of transmission links and optimal results are obtained. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1632–1536, 2015
Slot antenna with multiband functionality in wireless industrial applications
Authors: Shafei Shahin , Sedgeechongaraluye‐yekan T. 
Published: April 2015

ABSTRACTA unique slot antenna, for multiband applications with asymmetric coplanar waveguide feed is proposed. Different form of strips is used as grounded slits for providing multiband functionality. By adopting the proposed strips length and size, much wider impedance band width is achieved in two bands. Beside that an asymmetric feeding method is applied with rectangular patch for generating new resonances and good matching. By utilizing this novel method, good impedance matching is seen in both bands. The antenna size is only about 40 × 40, which covers the frequency band from 4.8 to 6.5 GHz in band#1 and from 7.8 to 8.4 GHz in band#2 for VSWR <2. Furthermore, by variation of strips positions and patch lengths, the control of the impedance band width and resonances are steered. Both simulated and measured results are illustrated and compared with each other to guaranties antenna's performance. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1653–1655, 2015
Implementation of veriloga GaN HEMT model to design RF switch
Authors: Majumdar Shubhankar , Bag Ankush , Biswas Dhrubes 
Published: April 2015

ABSTRACTGaN HEMT model has been implemented in designing of RF switch through VerilogA. The VerilogA model is formed by experimental data as obtained from DC and RF characteristics of the HEMT. A look‐up‐table based VerilogA model has been prepared to simulate the RF switch in Cadence's spectre. The simulated value of the switch property i.e. isolation and insertion loss is found to be −40 dB to −35 dB and −0.5 dB to −2.5 dB, respectively in the 0.5–2.5 GHz frequency range. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1765–1768, 2015
Miniaturized band‐pass filter based on composite right‐/left‐handed transmission‐line unit cell
Authors: Pandey Arvind Kumar , Gaurav Yatindra , Chauhan R. K. 
Published: April 2015

ABSTRACTThis article presents the design and implementation of a band‐pass filter using a novel composite right‐/left‐handed (CRLH) structure. To minimize the overall size of filter, the concept of CRLH metamaterial is used. Only one unit cell of CRLH is used in this filter to reduce size. The proposed CRLH structure for this filter shows smaller size than the filters designed using traditional methods. The designed filter is simulated and, thereafter, validated by physical realization and its testing. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1713–1717, 2015
p‐i‐n diode phase shifter in waveguide structure
Authors: Parnes Michael , Vendik Orest 
Published: April 2015

ABSTRACTA calculation procedure is proposed to design the p‐i‐n diode phase shifter based on the waveguide transmission line. The laboratory sample of five‐bit phase shifter designed using the proposed procedure was fabricated and measured at 32–36 GHz. It provides the following phase shifts bits: 11°, 22°, 45°, 90°, 180°. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1666–1671, 2015
Development of the antipodal Vivaldi antenna for detection of cracks inside concrete members
Authors: Moosazadeh Mahdi , Kharkovsky Sergey 
Published: April 2015

ABSTRACTUltrawide band (UWB) nondestructive testing and evaluation techniques can provide the detection of defects and damages in construction materials and members. The development of UWB antennas with proper dimensions and high performance for these systems is one of the major challenges. In this letter, an antipodal Vivaldi antenna (AVA) has been developed to be used in UWB techniques for nondestructive detection of cracks in concrete members. To obtain a desirable antenna performance including the wider impedance bandwidth, the higher directivity, and higher front‐to‐back ratio rectangular‐shaped slits (RSS) and a half‐circular‐shaped lens (HCSL) have been added in the design of a conventional tapered slot AVA. A parametric study on the dimensions of the slits is provided to optimize performance and size of the proposed antenna. The optimum size of the proposed antenna is 40 × 80 × 0.508 mm3, and it operates over the frequency range from 3.4–40 GHz. It is shown that the RSS increase impedance bandwidth especially at the lower frequencies. Directivity of the proposed antenna at higher frequencies has been increased by the HCSL. The feasibility of the proposed antenna for nondestructive evaluation of concrete members is demonstrated by investigation into its performance with concrete specimens possessing an air‐gap inside a concrete specimen. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1573–1578, 2015
Development of high gain multiband antenna with centre‐offset copper strip‐based periodic structure
Authors: Islam M. T. , Alam M. S. , Misran N. , Ismail M. , Yatim B. 
Published: April 2015

ABSTRACTIn this article, two coplanar waveguide‐fed high gain multiband antennas with and without uniplanar copper strip‐based electromagnetic band gap (CS‐EBG) structure are proposed for portable wireless applications at 2.1, 2.4, 3.5, 5.2, 5.4, and 5.8 GHz. The initial multiband antenna is realized by patch‐ground shape modification and open‐ended rectangular slot insertion on the patch. The two layer uniplanar CS‐EBG structure is composed of square ring periodic elements of copper strips of different widths and gaps. The top unit cells are placed at an offset position with respect to the bottom layer, which is new technique applied to obtain multiple resonances from such a simple and compact planar structure. The antenna, when combined with the CS‐EBG structure, still preserved its multiband characteristics and produced directional pattern because of the reflecting property (like artificial magnetic conductor, AMC) of the CS‐EBG/AMC structure behind it, which was donut and omnidirectional shape in case of the antenna alone. The initial antenna gain is 5 dBi while the final antenna gain is improved to approximately 12 dBi at the first band and more than 6 dBi at other bands. Thus, the developed square ring copper strip structure is very effective to improve the antenna performances and finally resulted in a high gain antenna. Both of the configurations with and without the CS‐EBG/AMC are fabricated and tested, and the measurements are well agreed with the simulations. Despite of the slight frequency shifting, the antenna is still suitable for the portable wireless operation such as Wi‐Fi, WiMax, WLAN/HIPERLAN and even for LTE/4G technology at some frequencies. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1608–1614, 2015
Study of trapezoidal toothed log‐periodic antenna fed through tapered microstrip line‐to‐coplanar stripline transition
Authors: Patre Situ Rani , Singh Soni , Singh S. P. 
Published: April 2015

ABSTRACTThe simulation and experimental studies of a wideband trapezoidal toothed log‐periodic (balanced type) antenna excited through tapered microstrip (MS) line to coplanar stripline (CPS) transition (balanced type feed) are presented in this paper. Effect of the balanced type feed on the performance of antenna is discussed. The tapered MS line provides impedance matching between CPS transition, which is connected to antenna and 50‐Ω coaxial cable. A quarter‐wavelength radial stub at the output end of transition is responsible for field transition. The simulated reflection coefficient‐frequency characteristic of the combination of the antenna and tapered MS line‐to‐CPS transition is compared with the corresponding characteristic of the antenna fed through microstrip‐to‐parallel strip balun. Further, the simulated input and radiation characteristics of the antenna fed through the proposed transition are also compared with corresponding experimental results. The antenna along with transition achieves simulated reflection coefficient bandwidth (reflection coefficient ≤ −10 dB) of 7.67:1 (0.9–6.9 GHz). The simulated peak realized gain and radiation efficiency vary in the range 0.25−5.6 dB and 71−95%, respectively over the operational bandwidth of the antenna‐transition combination. The simulated input and radiation characteristics of the proposed antenna are nearly in agreement with the corresponding measured results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1671–1677, 2015
Wideband RCS reduction and gain enhancement microstrip antenna using chessboard configuration superstrate
Authors: Zheng Yue‐jun , Gao Jun , Cao Xiang‐yu , Li Si‐jia , Li Wen‐qiang 
Published: April 2015

ABSTRACTA novel design for wideband radar cross section (RCS) reduction and gain enhancement microstrip antenna is proposed. Two 180° phase difference and modified artificial magnetic conductor cells are utilized to combine chessboard configuration superstrate (CCS). The bottom side of CCS is etched slot and exploited to construct Fabry–Perot resonance cavity with ground plane of a microstrip antenna. The CCS can enable the primary antenna to obtain gain enhancement and RCS reduction simultaneously. Measured results show that the proposed antenna gain is enhanced by about 4.8 dB at 9.6 GHz and its 3 dB gain enhancement bandwidth is from 9.1 to 10.5 GHz. The half power beamwidth is suppressed from 101° to 12° in E‐plane, while it is only 14° in H‐plane, decreased by about 75° compared with the primary antenna. Meanwhile, the antenna RCS is dramatically reduced in a broad frequency range from 8.0 to 14.0 GHz, which contains the operation band of the proposed antenna. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1738–1741, 2015
Numerical and experimental verification of a trireflector compact antenna test range in the terahertz band
Authors: Lu Zejian , Liu Xiaoming , Wang Hai , Yao Yuan , Chen Xiaodong , Yu Junsheng 
Published: April 2015

ABSTRACTNumerical and measured results of the quiet zone performance of a trireflector compact antenna test range (CATR) system in the terahertz band are presented in this letter. A modular Gaussian beam (GB) analysis method, which consists of frame‐based Gabor transformation, GB reflection and a 3D GB diffraction technique, was implemented to evaluate the quiet zone performance. Compared to geometrical optics method, this method is valid in predicting the field distribution in the caustic region. Moreover, simulation results of the CATR system demonstrated a superior efficiency to the physic optics method, especially in the terahertz range. Measured results show that 70% quiet zone usage can be achieved with amplitude and phase ripples less than 1.2 dB and 15°, respectively in the central frequencies. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1686–1689, 2015
A novel finite element time domain method for nonlinear Maxwell's equations based on the parametric quadratic programming method
Authors: Zhu Bao , Yang Hongwei , Chen Jiefu 
Published: April 2015

ABSTRACTA finite‐element time‐domain method is developed for Maxwell's equations with nonlinear media. Compared with conventional nonlinear numerical methods, the proposed scheme is not based on iterations, but using the quadratic programming method. The nonlinear constitutive relations are treated as a series of linear complementary problems, thus, this scheme presents very good convergence behavior in computation. Numerical results demonstrate the validity of the proposed method. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1640–1645, 2015
16‐QAM all‐optical OFDM system performance evaluation with time and frequency offsets
Authors: Ali Mumtaz , Dai Bo , Wang Xu 
Published: April 2015

ABSTRACTIn an all‐optical orthogonal frequency division multiplexing (AO‐OFDM) system, symbol time misalignment (STM) and subcarrier frequency offset (ScFO) between transmitter and receiver result in intercarrier interference (ICI) and intersymbol interference, leading to a degradation of the system performance. In this article, an analytical study of the impacts of STM and ScFO on the bit error rate (BER) performance of superchannel based on 16‐QAM modulated all‐optical OFDM transmitter with coherent detection is conducted. Under the condition BER = 10−3, maximum acceptable relative deviations for the STM and ScFO are 3.2 and 5.5% in AO‐OFDM system. A delay line interferometer (DLI)‐based ICI suppression method is proposed, and the results demonstrate that the tolerances to relative deviations for the STM and ScFO increase to 29 and 10% without cyclic prefix. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1593–1597, 2015
Modified theta‐shaped monopole antenna with defected ground structure for UWB applications
Authors: Singhal Sarthak , Singh Amit Kumar 
Published: April 2015

ABSTRACTA compact modified theta‐shaped monopole antenna for ultrawideband communication is presented. It consists of a modified theta‐shaped radiator fed with a modified microstrip feedline and rectangular notch‐loaded quarter elliptical coplanar waveguide ground plane. An impedance bandwidth of 4.35–20.75 GHz (131%) below −10 dB reflection coefficient line is achieved. The designed antenna structure has nearly omnidirectional radiation pattern in H‐plane and bidirectional pattern in E‐plane. The cross polarization level is also 20 dB lesser than copolarization level in every direction at lower frequencies. The performance of the designed antenna structure for three substrate materials, that is, FR‐4 epoxy, carbon nanotubes, and Ni0.2Co0.2Zn0.6Fe2O4, are also studied. The experimental and simulation results are found to be in good agreement. The designed antenna structure has advantage of wider bandwidth along with smaller dimensions as compared to previously reported monopole structures. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1625–1632, 2015
Analysis of shoot‐through current of supply modulator for envelope‐tracking techniques
Authors: Yoo Jinho , Yoon Seokhyun , Lee Changhyun , Park Changkun 
Published: April 2015

ABSTRACTIn this work, we analyze the conduction and switching losses of a supply modulator for envelope‐tracking techniques. In particular, the conduction and switching losses in the class‐D chain of the supply modulator are calculated to enhance the efficiency of the supply modulator. From the calculated results, the number of stages and fan‐out in the multiple stages of the class‐D chain are optimized. To verify the feasibility of the analyzed results, we designed a supply modulator using a 180‐nm RF CMOS process. From the measured results, we successfully prove the feasibility of the analyzed results. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1579–1983, 2015
Compact SPDT switchable bandpass filter with single and differential outputs
Authors: Chen Chang‐Sheng , Lin Yo‐Shen 
Published: April 2015

ABSTRACTA single‐pole‐double‐throw (SPDT) switchable bandpass filter (BPF) based on capacitively loaded multicoupled line is proposed. The output port can be designed as either single‐ended or differential one. The proposed multifunctional circuit can effectively integrate the functions of SPDT RF switch, BPF, and balun. Compact size and good performance are achieved. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1705–1707, 2015