bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low‐cost wideband double‐layer microstrip coupled‐line directional coupler with high directivity
Authors: Esfeh Babak Kazemi , Raskin Jean‐Pierre , Van Moer Wendy 
Published: April 2014

ABSTRACTIn this article, a low‐cost double‐layer microstrip structure with a gap space between the two substrate layers is used to develop a microstrip coupled‐line directional coupler with high directivity. The proposed design shows a high directivity (more than 20 dB) over a wide frequency bandwidth (more than 2 GHz). The double‐layer directional coupler, designed on FR4 substrate material at 2.4 GHz provides more than 30 dB isolation. The simulation and measurement results are in good agreement. By applying a simple and low‐cost fabrication process and design, the directivity of the directional coupler is enhanced by more than 10 dB compared with a microstrip structure. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1570–1575, 2014
Nested metamaterials antenna for RFID traceability
Authors: Naoui Seif , Latrach Lassaad , Gharsallah Ali 
Published: April 2014

ABSTRACTIn this article, we propose a new approach to study a suitable structure of metamaterial antennas for radio frequency identification (RFID) technology that operates in the UHF band. This antenna is constituted by a dipole associated to resonant materials. These materials are the split ring resonators forming the nested metamaterial by a network fee specific and homogeneous structure that can produce an effective negative permeability. Thanks to the effect metamaterials, we can improve the performance and reduce the size of the studied antenna, which is very important for the RFID applications. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1622–1626, 2014
Design of an X/KU band OMT based on a Bøifot junction using capacitive posts
Authors: Park Kwang Woo , Choi Hak Keun 
Published: April 2014

ABSTRACTIn this article, an orthomode transducer (OMT) using a Bøifot junction with capacitive posts for the X/Ku band is proposed. The structure of the proposed OMT is based on the Bøifot junction with capacitive posts, to obtain wideband characteristics, and to improve return loss. The proposed OMT consists of three parts: four‐port junction, vertical port, and horizontal port. The proposed OMT is fabricated, and then measured, to show return loss over 20 dB, insertion loss less than 0.99 dB, and isolation over 50 dB, for vertical and horizontal polarization of the X/Ku band. It is proved that the computed results agree well with the measured ones. Therefore, it is confirmed that the proposed OMT can be used for satellite communication systems. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1617–1622, 2014
Very compact palmate leaf‐shaped CPW‐FED monopole antenna for UWB applications
Authors: Fakharian Mohammad M. , Rezaei Pejman 
Published: April 2014

ABSTRACTThis article presents a very compact coplanar waveguide‐fed planar monopole antenna for ultrawideband (UWB) applications. The antenna consists of a palmate leaf‐shaped radiator with a modified shaped ground plane on the same side of the substrate. The measured impedance bandwidth of the proposed antenna is from 3.08 to over 14 GHz with a ratio of about 4.6:1 for VSWR ≤ 2. Experimental results show that the proposed antenna has stably omnidirectional H‐plane radiation patterns with low cross‐polarization level and average peak gain of 3 dBi across the UWB. The antenna dimensions are restricted to 13.5 × 14.8 × 0.8 mm3. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1612–1616, 2014
Infrared imaging in the analysis of planar antennas
Authors: Díaz de León Torres H. , Kolosovas‐Machuca S. , Simón Jorge , Vera‐Reveles Gustavo , Briones Edgar , González Francisco J. 
Published: April 2014

ABSTRACTIn this study, a noninvasive method based on infrared thermography is presented to obtain the resonant frequency of a dipole antenna in the microwave region. The study was performed by visualizing the temperature increase due to the Joule heating of the antenna fed by a voltage source. Results show a significant increase in dissipated heat at 830MHz where the resonance is expected. This method can be used to measure planar antennas noninvasive and in‐situ without having to take them to a specialized antenna‐measurement facility. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1610–1612, 2014
Signal upconversion for a radio‐over‐fiber system with modulation types based on a frequency quadrupling technique
Authors: Lin Jhe‐Min , Ho Wen‐Jeng , Chang Yu‐Peng , Peng Peng‐Chun , Lu Hai‐Han 
Published: April 2014

ABSTRACTIn this study, optical upconverted microwave frequency generation was experimentally demonstrated using a frequency quadrupling technique based on two types of baseband signal modulation in a radio‐over‐fiber (RoF) system. The measured results revealed that an error‐free transmission could be achieved without causing the periodic power fading affect, and that clear eye diagrams were obtained after a 20‐km transmission by using baseband/RF mixed‐signal external modulation. The proposed method is a feasible technique for generating a 622 Mbps (1.25 Gbps)/15 GHz frequency quadrupling RoF signal without using narrow‐band optical notch filters or sophisticated optical modulators. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1603–1610, 2014
A low profile dual‐band dual‐polarized patch antenna array with integrated feeding network for pico‐base station applications
Authors: Li Jinxin , Yang Shiwen , Li Bing , Nie Zaiping 
Published: April 2014

ABSTRACTA low profile dual‐band dual‐polarized patch antenna array for pico‐base station is presented in this article. The proposed antenna array uses a stacked configuration composed of three layers of substrates, with circular patches etched on the upper side of the upper substrate and quasi‐cross‐shaped slotted circular patches etched on the upper side of the middle substrate. A novel feeding network composed of two hybrid couplers and four power dividers is printed on the bottom side of the lower substrate. Simulated and measured results show that the proposed antenna array achieves a return loss lower than −14 dB over the dual‐frequency band of 1.92–1.98 and 2.11–2.17 GHz. Moreover, stable radiation patterns with a peak gain of 10.7–11.7 dBi is obtained within the operating band. The proposed antenna array is easy to realize shaped beam and can be used for pico‐base station antennas. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1594–1600, 2014
Design of low‐power CMOS VCO based on current‐reused topology with center‐tapped inductor bias
Authors: Hsu Meng‐Ting , Chung Cheng‐Chuan , Ou An‐Cheng 
Published: April 2014

ABSTRACTThis article presents a completely integrated 1.1 V 5.15 GHz CMOS voltage‐controlled oscillator (VCO) with self‐body‐biased technique to save the power consumption. MOS varactors are used to maintain a wide tuning range. The VCO was measured with a 1.1 V supply voltage and the tuning range of 16% from 5.15 to 6.05 GHz. The measurement of phase noise is −114.63 dBc/Hz at 1 MHz offset from the carrier frequency of 5.15 GHz. The VCO core power dissipation is 0.8 mW. The figure‐of‐merit is −189.8 dBc/Hz. The VCO circuit was implemented by TSMC 0.18 μm CMOS process. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1587–1590, 2014
Low‐profile multibranch monopole antenna with integrated matching circuit for Lte/Wwan/Wlan operation in the tablet computer
Authors: Lin Po‐Wei , Wong Kin‐Lu 
Published: April 2014

ABSTRACTA low profile, small‐size, planar tablet computer antenna for the long‐term evolution (LTE)/wireless wide area network and 2.4‐GHz WLAN operation is presented. The antenna is formed by three monopole strips configured into a compact configuration and printed on a thin FR4 substrate of size 10 × 40 mm2. A high‐pass matching circuit is integrated thereon, without increasing the antenna size, to greatly enhance the antenna's low‐band bandwidth to cover the LTE700/GSM850/900 operation (704–960 MHz) with a low‐antenna profile of 10 mm. The antenna's higher band is formed by two wide resonant modes contributed by the monopole strips and can cover the GSM1800/1900/UMTS/LTE2300/2500 operation (1710–2170/2300–2400/2500–2690 MHz). In addition, one of the resonant modes in the higher band can be adjusted to occur at about 2.4 GHz such that enhanced radiation characteristics for frequencies in the 2400–2484‐MHz WLAN band are obtained for the proposed antenna. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1662–1666, 2014
Compact dual‐band slot antenna with capacitor loading
Authors: Jin Zhe‐Jun , Yun Tae‐Yeoul 
Published: April 2014

ABSTRACTA compact dual‐band slot antenna with capacitor loading is proposed for the wireless local area network bands (2.4–2.49 and 5.15–5.35 GHz). The antenna is composed of a modified L‐shaped slot and a capacitor. The capacitor is used to generate two surface‐current paths on the ground and to miniaturize the antenna size. The proposed antenna has an omni‐directional radiation pattern with antenna peak gains of 2.2 dBi at 2.44 GHz and 2.7 dBi at 5.25 GHz. Radiation efficiencies are greater than 60% over the operating frequency bands. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1653–1658, 2014
Compact microstrip dual‐band bandpass filter using short‐circuited stub‐loaded open loop resonators
Authors: Ma Xing‐Bing , Zhang Feng‐Shan 
Published: April 2014

ABSTRACTIn this article, a compact dual‐band microstrip bandpass filter is proposed using two short‐circuited stub‐loaded open loop resonators and two common open loop resonators. The short‐circuited stub‐loaded resonators can generate two resonant modes. Under odd mode, the short‐circuited stub at the central does not affect the resonant frequencies, and four resonators tightly coupling with each other work at the same frequencies, a wideband passband is obtained. Whereas under the even mode, considering the influences from short‐circuited stubs, the resonant frequencies are decided only by two short‐circuited stub‐loaded resonators, two common resonators are seen as parts of feedlines connected to 50 Ω. A new transmission zero is created between two passbands to improve the selectivity. Good agreement is achieved between simulation and measurement. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1651–1653, 2014
Higher order mode generation in millimeter wave regime by directly launched fundamental mode
Authors: Choe Mun Seok , Choi EunMi 
Published: April 2014

ABSTRACTWe report on a novel method to generate higher order modes in the frequency range of millimeter and submillimeter wave regime. The method uses magnetic coupling scheme between waveguide fundamental mode and a cavity mode. A TE62 mode at W‐band was considered for design using the proposed scheme. The suggested method simplifies a mode generator design allowing direct feeding via a standard fundamental waveguide and also provides a compact mode generator to design extremely higher order mode in a cavity. In addition, it opens a new and novel way to develop high power high gain gyrotron amplifiers at millimeter and submillimeter wave regime. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1648–1651, 2014
Uwb multiresonance antenna with rejection of intelligent transport system band using a cross‐shaped conductor‐backed plane
Authors: Ojaroudi Nasser , Ghadimi Noradin 
Published: April 2014

ABSTRACTThis article presents an ultrawideband (UWB) microstrip monopole antenna with band‐notched function around 5.79–6.40 GHz to avoid any interference from the intelligent transport system (ITS). The proposed antenna consists of an ordinary square radiating patch, a feed‐line and a modified ground plane with pair of rotated H‐shaped slots and cross‐shaped conductor‐backed plane. By cutting a pair of rotated H‐shaped slots, additional resonances at higher frequencies are excited and hence much wider impedance bandwidth can be produced, which provides a wide usable fractional bandwidth of more than 135%. In the proposed design, to generate the ITS band‐stop performance, a cross‐shaped conductor‐backed plane is embedded in the ground plane. The proposed antenna can operate from 3.02 to 16.5 GHz with VSWR < 2 and with a rejection band around 5.79–6.40 GHz. The antenna has an ordinary square radiating patch, therefore, displays a good omnidirectional radiation pattern even at higher frequencies. Simulated and measured results are presented to validate the usefulness of the proposed antenna structure for UWB applications. The proposed monopole antenna configuration is simple, easy to fabricate and has a small size of 12 × 18 × 1.6 m3. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1641–1644, 2014
A high‐performance low‐noise amplifier for 71–76, 76–77, and 77–81 GHz communication systems in 90‐NM CMOS
Authors: Lin Yo‐Sheng , Wang Chien‐Chin , Lee Guan‐Lin , Chen Chih‐Chung 
Published: April 2014

ABSTRACTA low power and wideband three‐stage millimeter‐wave low‐noise amplifier (LNA) for 71–76 GHz high‐speed point‐to‐point wireless link, and 76–77 GHz long‐range and 77–81 GHz short‐range automotive radars using standard 90‐nm CMOS technology is reported. T‐match technique is utilized to achieve simultaneously wideband input and output impedance matching, wideband power gain (S21) and wideband noise figure (NF) at W‐band. The LNA consumes 21.1 mW, achieving S11 better than −10 dB for frequencies 62.3–82.4 GHz, S22 better than −10 dB for frequencies 62.8–84.6 GHz, S12 better than −29 dB for frequencies 72–84 GHz, and group delay variation smaller than ±6.5 ps for frequencies 70–90 GHz. Additionally, high and flat S21 of 13.1 ± 1.5 dB is achieved for frequencies 72–84 GHz, which means the corresponding 3‐dB bandwidth is 12 GHz. Furthermore, the LNA achieves minimum NF of 6.2 dB at 78 GHz and NF of 6.8 ± 0.6 dB for frequencies 75–82 GHz, one of the best NF results ever reported for a W‐band CMOS LNA. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1673–1680, 2014
Nonadiabatic microfiber based mode‐locked erbium‐doped fiber laser using graphene
Authors: Sulaiman Azlan , Wadi Harun Sulaiman , Ahmad F. , Ahmad Harith 
Published: April 2014

ABSTRACTA new compact and low threshold mode‐locked Erbium‐doped fiber laser (EDFL) using nonadiabatic microfiber in conjunction with a graphene saturable absorber is demonstrated. The graphene was synthesized by electrochemical exfoliation of graphite at room temperature in 1% sodium dodecyl sulfate aqueous solution. Graphene flakes obtained from the process are mixed with polyethylene oxide as the host polymer to produce composite solution which acts as passive mode locker in the EDFL linear cavity. Mode‐locked laser, with a threshold of less than 10 mW, pulse repetition rate of 55.8 MHz, and pulse duration of 0.82 ps, is achieved. The EDFL operates at around 1531.8 nm with an average output from 0.1 mW, pulse energy of 2 pJ at the 980 nm pump power of 10 mW. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1670–1673, 2014
A wavelength spacing switchable and TUNABLE high‐birefringence fiber loop mirror filter
Authors: Bian Si‐Yuan , Ren Mei‐Qi , Wei Li 
Published: April 2014

ABSTRACTWe demonstrated an all‐fiber birefringent comb filter with tunable and switchable wavelength spacing. The comb filter is based on a fiber loop mirror (FLM) with three sections of high‐birefringence (HB) fibers and polarization controllers (PCs). The transmission characteristics of the birefringent FLM are dependent of the relative phase difference of the two orthogonal polarization modes and the rotational angles of the different HB fibers. By adjusting the PCs, four different wavelength spacings can be obtained; particularly, interleaving operation—halved and quartered wavelength spacing—can be effectively realized. By using a Jones matrix method, the transmission of the birefringent comb filter is analyzed. The theoretical analysis agrees with the experimental results. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1666–1670, 2014
Broadband dielectric loaded parallel coupled microstrip quadrature coupler
Authors: Ashraf Muhammad A. , Sebak Abdel Razik , Alhekail Zeyad O. , Alkanhal Majeed , Alshebeili Saleh 
Published: April 2014

ABSTRACTIn this article, a wideband dielectric loaded coupled line microstrip 90° hybrid coupler is proposed. The effect of changing the effective dielectric constant of substrate by dielectric loading is capitalized to tune the even‐ and odd‐mode velocities of coupled line to achieve wideband performance. Two different designs are perturbed by dielectric loading to achieve minimum amplitude and phase imbalance with good isolation. The simulated and measured results exhibit a coupling of 3 ± 0.7 dB across the band 3.5–10 GHz. The return loss and isolation are found to be better than 15 dB with 3° phase imbalance over the ultrawideband band. The designed coupler has compact size with a dimension of 30 × 20 mm2. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1694–1697, 2014
UWB UHF RFID TAG antenna with branch‐line slots for metallic objects
Authors: Tang Tao , Chen Xiaorong 
Published: April 2014

ABSTRACTA novel UWB ultrahigh frequency (UHF) radio frequency identification (RFID) tag antenna designed for metallic objects is proposed, which is fabricated on a flexible polyethylene terephthalate substrate for low‐cost production, whose relative permittivity is 3.8 and dielectric loss tangent is 0.02. The overall size of the proposed tag antenna is 56 × 10 × 0.8 mm3. It consists of two coplanar patches which are electrically connected to the metallic ground through two symmetrical shorting walls placed at both edge sides of the patches. The resonant frequency can be adjusted by changing the shorting wall length. Double‐symmetrical branch‐line slots are created to improve the antenna bandwidth. The simulated bandwidth is about 223.5 MHz, which covers the global UHF RFID frequency range. The experimental results show that the maximum read range of the proposed antenna is larger than 2.6 m when it is mounted on a test metal plate with a size of 150 × 150 × 8 mm3. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1689–1691, 2014
Linear response and enhanced sensitivity of Mach–Zehnder interferometer with optimized sensing length
Authors: Yang Tianfu , Wang Tianjiao , Zheng Chuantao , Wang Xibin , Zhang Daming 
Published: April 2014

ABSTRACTThrough a sensing length of 1,1515 µm, the integrated Mach–Zehnder interferometer sensor obtains a quadrature point and linear response in refractive index range of 1.31–1.42. The sensitivity is measured as 225.4 dB/RIU, and the response time is less than 20 s to solutions. Cost‐efficient polymers are used as waveguide materials, and a microfluidic system is achieved. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1697–1701, 2014
Sensing characteristics of in‐line Mach‐Zehnder interferometer based on magnetic fluid‐filled multimode photonic crystal fiber
Authors: Luo Jian‐hua , Zhang Gui , Gu Yanran , Gong Shuhang , Quan Guofan , Xie Nanjie , Wang Tianxi 
Published: April 2014

ABSTRACTAn in‐line Mach–Zehnder interferometer (MZI) with a magnetic fluid‐filled multimode photonic crystal fiber (PCF) fusion spliced into two standard optical fibers was proposed. The interference is induced by the two core mode LP01 and LP11 due to the special air hole structure of PCF, which is insensitive to bending and the surrounding refractive index (SRI). High strain sensitivity of 3.7 pm/µε at 1290 nm is achieved. The temperature sensitivity (7.6 pm/°C) is even lower than fiber Bragg grating (FBG). In addition, interference intensity of MZI is sensitive to magnetic field intensity. This structure provides a property for simultaneous measurement of strain and magnetic field and avoiding cross sensitivity on temperature and SRI with a simple process and low cost. Cascading other sensing element such as FBG, LPFG, it also provides a property for simultaneous measurement of multiparameters. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1720–1724, 2014
Index‐insensitive curvature sensor based on holey fiber modal interferometer
Authors: Guan Shouhua , Yu Qingxu 
Published: April 2014

ABSTRACTAn optical fiber curvature sensor based on holey fiber (HF) modal interferometer is demonstrated experimentally. The sensor is fabricated by a length of 2.4 cm HF which is spliced between two single mode fibers. Different resonant peaks have different curvature characteristics, and the sensitivity of 1.815 nm m−1 is achieved in the range of 0–0.905 m−1 for the peak around 1504 nm. The sensor is insensitive to the surrounding refractive index, so it is more suitable for index‐insensitive wavelength‐dependent curvature measurement. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1709–1711, 2014
Reconfigurable microstrip annular ring antenna for circular polarization diversity
Authors: Pyo Seongmin , Kim Nam , Kim Joung‐Myoun 
Published: April 2014

ABSTRACTThis article presents a novel design of a microstrip annular ring antenna with reconfigurable circular polarization (CP) diversity by switching one corner perturbation segment. The proposed antenna has a construction of a single‐feed annular ring as a radiator and frequency perturbing elements at one diagonal edge. To achieve the condition with left‐ and right‐handed CP diversity, the perturbations of the proposed antenna uses the concept of positively and negatively slot‐loaded annular ring. By controls of two diodes' states in the perturbation, both of CP senses have been easily alternated. The simulated and measured results show good and symmetrical radiation patterns at each resonant frequency. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1706–1709, 2014
Erratum: Fields produced at any distance by a Hertzian dipole – generalizations – approximations
Authors: M. Knop Charles 
Published: April 2014

ABSTRACTThe exact integral expressions for the azimuthal magnetic field, Hφ (r/h,θ), and the polar electric field, Eθ (r/h, θ), produced at any polar‐angle, θ, and at any distance, r, from the center of a Hertzian dipole of height h were recently derived‐reported in this journal (Knop, Microwave Opt Technol Lett 54 (2012), 1970–1975). Numerical computations‐plots of these fields as a function of the polar angle θ with the distance parameter of r/h were there given for the case of a dipole of h/λ = 0.10, where λ is the free space operating wavelength. These computations‐plots are here extended to the cases of h/λ = 0.05 and 0.01. Computations and plots of these fields as a function of r/h with θ as a parameter are also given. Critical comparisons to the h/λ = 0.10 case are then made and generalizations formed for the fields' behavior as h/λ decreases. Approximate closed‐form equations/formulas for the fields are also presented.
2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2726–2734, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27881.
2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1728–1729, 2014
Erratum: Electromagnetic bandgap resonators synthesized using ceramic injection molding
Authors: Henderson Rashaunda , Tang Zhizhong , Liu Shaojun , Petras Michael , Aberle James P. , Newman Nathan 
Published: April 2014

ABSTRACTOriginally published in Microwave Opt Technol Lett 56: 371–375, 2014. © 2014 Wiley Periodicals, Inc. View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.28113. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1727–1728, 2014