bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat treatment of egg white controls allergic symptoms and induces oral tolerance to ovalbumin in a murine model of food allergy
Authors: Watanabe Hiroko , Toda Masako , Sekido Haruko , Wellner Anne , Fujii Tomoyuki , Henle Thomas , Hachimura Satoshi , Nakajima‐Adachi Haruyo
Published: August 2013

Scope

Heated foods often present low allergenicity, and have recently been used in specific oral immunotherapy for food allergies. However, the influence of heating on tolerogenicity of food allergens is not well elucidated. Here, we investigated biochemical, allergenic, and tolerogenic properties of heated egg white (EW) using a murine model of food allergy.

Methods and results

Raw EWs were treated at 80°C for 15 min (80EW, mild heating condition), 100°C for 5 min (100EW, cooking condition), or 121°C for 40 min (121EW, retort pouch condition), and freeze‐dried. A transgenic OVA23–3 mice model expressing T‐cell receptor specific for ovalbumin (OVA, a major EW allergen) induced Th2 cells and IgE production, and presented intestinal inflammation when fed untreated EW diet. 80EW‐fed mice presented only moderate inflammation but high Th2 responses. 100EW‐fed mice did not present inflammation but induced tolerance as seen in reduced T‐cell responses and IgE levels. 100EW demonstrated higher digestive stability and slower absorption in intestine, compared with untreated EW and 80EW. 121EW was strongly aggregated, was not absorbed well, and developed Th1 responses without tolerance induction.

Conclusion

OVA in EW treated only under a particular heat condition (e.g. 100°C for 5 min) lost allergenicity, but possessed tolerogenicity.
Analysis of a coaxial probe‐fed circular waveguide
Authors: Dey Ranajit , Chakrabarty S. B. , Jyoti Rajeev
Published: August 2013

This article presents the investigation on the applicability of variational technique for the estimation of input impedance of a coaxial line fed probe in a circular cylindrical waveguide based on thin current approximation. In this work, the lower limit of diameter of the probe for which thin current approximation is valid has been established. The variation of input impedance has been studied as a function of probe height, short length from the probe as well as diameter of the probe. The convergence of the solution based on variational technique is checked in terms of the number of higher order modes of circular cylindrical waveguide excited at the asymmetrical junction of probe. The limitation of the existing technique has been ascertained using the finite element method based simulator high frequency structure synthesizer (HFSS) and experimental validation. The simulated result based on HFSS is in excellent agreement with the experimental results. Bandwidth performance with variation in diameter has also been studied using HFSS simulator with varying probe diameter. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2652–2656, 2013
Wideband nonlinear characteristics of random multiwalled carbon nanotubes network
Authors: Oueriemi I. , Raskin J.‐P. , Choubani F. , Huynen I.
Published: August 2013

In this work, multiwalled carbon nanotubes (MWCNTs) were randomly deposited in gaps of microstrip interdigitated capacitive (IDC) structure. Measured I‐V characteristics show nonlinear behavior of MWCNTs. Supported by an analytical Schottky‐based model, the nonlinear mechanism is attributed to semiconductor/metallic (S/M) junction properties. Measuring the IDC over a wide frequency band, from 1 kHz up to 3 GHz, we demonstrate there is a maximum frequency (∼10 MHz) beyond which the nonlinear behavior of the MWCNTs network vanishes. An equivalent lumped element circuit for MWCNTs‐based IDC describes well the measured behavior up to 3 GHz. Thanks to the extracted equivalent circuit, we demonstrate that the capacitive couplings between MWCNTs dominate over nonlinear effects above 10 MHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2648–2652, 2013
X‐band MMIC GaN power amplifier for SAR systems
Authors: Giofre Rocco , Colantonio Paolo , Giannini Franco
Published: August 2013

This contribution describes the design, realization, and test of a compact X‐band GaN MMIC high power amplifier (HPA) for synthetic aperture radar. The HPA represents the first step toward the realization of a fully integrated GaN transmitter/receiver (Tx/Rx) for X‐band applications. The circuit is designed in a two stage configuration and it is fully matched to 50 Ω input and output impedance. The chip area is less than 10 mm. Experimental results show an output power close to 42 dBm with a gain of 16 dB (at 3 dB of compression) and a ripple lower than 0.5 dB from 8.6 to 10.6 GHz frequency range. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2611–2616, 2013
Fiber‐length‐dependence phase noise of injection‐locked optoelectronic oscillator
Authors: Hong Jun , Yao Sheng‐Xing , Li Zu‐Lin , Huang Jun‐Xin , Fang Xiao‐Wei , Guo Jian
Published: August 2013

A novel model of injection‐locked dual optoelectronic oscillator (ILD‐OEO) is proposed and verified by experiments in this article. We not only built an accurate model for ILD‐OEO but also analyzed the influence of fiber length on the white noise‐limited phase noise of ILD‐OEO. Results show that the single sideband (SSB) phase noise would increase when fiber delay line is long enough. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2568–2571, 2013
The noise figure and gain improvement of double‐pass C‐band EDFA
Authors: Yucel Murat , Aslan Zuhal
Published: August 2013

In this study, the noise figure (NF) improvement is demonstrated in double‐pass C‐band erbium‐doped fiber amplifier. It is used the short length of unpumped erbium doped fiber (EDF) within a circulator‐based loop mirror which is reduced amplified spontaneous emission (ASE). The unpumped EDF attenuates part of the ASE that is then reflected back for a double pass configuration which in turn, helps to improve the gain and NF. The proposed configuration has lower NF and higher gain than conventional double pass scheme. Thus, it can be easily applied for practical application. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2525–2528, 2013
Capacity enhancement of virtual‐mirror‐based multiwavelength Brillouin‐erbium fiber laser
Authors: Rahman Zubaidah Abd , Hitam Salasiah , Al‐Mansoori Mohammed H. , Abu Bakar Muhammad H. , Mahdi Mohd A.
Published: August 2013

An enhanced multiwavelength Brillouin‐erbium fiber laser with virtual mirror concept is demonstrated. The performance of three linear amplifier schemes is investigated and optimized. Wide tuning range of 39 nm and maximum of nine laser lines are achieved utilizing a 915 nm pump laser at 616 mW pump power. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2549–2553, 2013
Design and implementation of dual‐band and triple‐band substrate integrated coaxial line filters
Authors: Jiang Mei , Hong Wei , Zhang Yan
Published: August 2013

In this article, dual‐band and triple‐band filters are proposed based on the substrate integrated coaxial line (SICL) technique. The SICL resonator and the coupling between the bandpass–bandpass resonators and bandpass–bandstop resonators are investigated, then single‐bandpass, dual‐bandpass, and triple‐bandpass filters are designed, fabricated, and measured. The dual‐band or triple‐band filters are equivalent to the combinations of one bandpass and one or two bandstop filters, and so can be easily synthesized from the generalized lowpass prototypes with Chebyshev responses. The measured results are in good agreement with the simulations. A size reduction of more than 45% has been achieved compared with the published substrate integrated waveguide filters. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2734–2738, 2013
Fields produced at any distance by a Hertzian dipole – generalizations – approximations
Authors: Knop Charles M.
Published: August 2013

The 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
A CMOS quadrature VCO implemented with direct capacitor injection‐locking
Authors: Jang Sheng‐Lyang , Lin Yu‐Sheng , Chang Chia‐Wei , Hsue Ching‐Wen , Juang Miin‐Horng , Teng Heng‐Fa
Published: August 2013

This article presents a new quadrature voltage‐controlled oscillator (QVCO). The LC‐tank QVCO consists of two first‐harmonic injection‐locked oscillators (ILOs). The outputs of one ILO are injected to the common nodes of capacitors on the other ILO and vice versa so as to force the two ILOs operate in quadrature. At the supply voltage of 1.1 V, the total power consumption is 5.94 mW. The free‐running frequency tuning range is 11.5%, tunable from 6.56 to 7.36 GHz as the tuning voltage is varied from 0.0 to 2 V. The QVCO has been implemented with the TSMC 0.18‐μm CMOS technology and the die area is 0.504 × 0.803 mm2. The measured phase noise at 1‐MHz offset is −123.01 dBc/Hz at the oscillation frequency of 7.34 GHz and the figure of merit of the proposed QVCO is about −192.5 dBc/Hz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2528–2531, 2013
Compact UWB power divider with tunable notch‐band based on dual‐mode SIR
Authors: Chen Lei , Wei Feng
Published: August 2013

An ultra‐wideband (UWB) power divider (PD) with an electronically tunable notch‐band based on single dual‐mode stepped‐impedance resonator (SIR) is investigated in this article. The proposed UWB PD is based on conventional Wilkinson PD, while two folded shunt quarter‐wavelength short‐circuited stubs are adding to two symmetrical output ports. The dual‐mode SIR with a varactor diode and dc bias is studied and used to generate desired tunable notched band. The predicted results are compared with measured data and good agreement is reported. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2709–2712, 2013
Bandwidth enhancement using gap‐coupled hexagonal microstrip antennas in L band
Authors: Rashmi Ritu , Prasan Ray Kamla , Duttagupta Sidhartha P.
Published: August 2013

New configurations, involving parasitic gap coupling of identical hexagonal microstrip antennas, are investigated to enhance the bandwidth. A better coupling between the driven and the parasitic patches is realized owing to the straight sides of the hexagonal microstrip antennas. The overall configuration exhibits an enhanced gain due to the increased aperture size. Different gap‐coupled configurations, including a novel configuration of the off‐axis gap coupling of three hexagonal microstrip antennas, are presented. For this novel configuration, measured bandwidth as large as 101.2 MHz at the center frequency of 1.884 GHz has been obtained, this is almost four times as compared to that of a single hexagonal patch. Both on‐axis and off‐axis gap coupling of three hexagonal microstrip antennas are explored and the off‐axis configuration demonstrates a bandwidth enhancement of ∼1.35 times over that of the on‐axis configuration. For all the configurations, measured and simulated bandwidths are in close agreement. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2703–2709, 2013
Reconfigurable bandstop filter with tunable center frequency and bandwidth using piezoelectric transducer
Authors: Jun Sungyun , Chang Kai
Published: August 2013

A reconfigurable bandstop filter with tunable center frequency and bandwidth using a piezoelectric transducer (PET) is presented. The proposed reconfigurable bandstrop filter consists of a PET and two quarter‐wavelength open‐stub microstrip lines. Tuning center frequency and bandwidth are achieved by varying the dielectric constants of a quarter‐wavelength open‐stub microstrip line using a controlled dielectric perturber under a PET in two quarter‐wavelength open‐stub microstrip lines. The proposed filter has a 8.7% tuning range at center freuqnecy from 4.62 to 5.06 GHz and 29% tuning range of bandwidth (>25 dB) from 990 to 1280 MHz with varied DC voltages. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2670–2672, 2013
Bandwidth and gain enhancement of a series‐fed two‐dipole array antenna using nearby parasitic director
Authors: Yeo Junho , Lee Jong‐Ig
Published: August 2013

This article presents a simple method of enhancing the bandwidth and gain of a series‐fed two‐dipole array (STDA) antenna by using a nearby parasitic director. In order to improve the bandwidth and gain characteristics of the STDA antenna, a parasitic director using a single strip is employed at a location close to the top dipole element. The effects of the location and size of the director on the impedance bandwidth and realized gain characteristics are investigated. A prototype of the proposed antenna is fabricated on an FR4 substrate, and its performance is compared with the conventional STDA antenna operating in a frequency band of 1.7–2.7 GHz with a gain > 5 dBi. The experimental results show that the enhancement in the bandwidth for a voltage standing wave ratio < 2 is 18.53%, and the improvement in the bandwidth for a gain > 5 dBi is 32.75%. In addition, the increment in the averaged peak gain for a gain > 5 dBi is 0.85 dB. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2782–2787, 2013
Reconfigurable bandpass filter with center frequency and bandwidth control
Authors: Psychogiou Dimitra , Peroulis Dimitrios
Published: August 2013

This article presents a bandpass filter with independent center frequency and bandwidth control. It is based on four frequency‐reconfigurable resonators arranged in a series cascade of a second‐order bandpass filter and a dual‐behavior resonator. A measured bandpass filter response with variable bandwidth between 440 and 0 MHz is demonstrated at 3.6 GHz. The center frequency of the filter can be continuously varied between 2.76 and 3.79 GHz (1.4:1) with continuous bandwidth variation between 300 and 100 MHz (3:1) for a minimum out‐of‐band isolation of −15 dB and insertion loss between 0.76 and 2.5 dB. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2745–2750, 2013
A novel ultrawideband bandpass filter with one notch‐band and wide stopband
Authors: Yang Fan , Wei Feng , Liu Shu‐Fang , Shi Xiao‐Wei
Published: August 2013

A novel ultrawideband bandpass filter with one notch‐band, high selectivity, and wide stopband is investigated in this article. The basic filter is composed of two microstrip‐slot transitions with novel annular stubs, which are used to obtain the required bandwidth with high selectivity. And, a cross‐coupling between the feed lines (input and output) is introduced to broaden the stopband. In addition, a short‐circuited stepped‐impedance resonator is used to obtain one notch‐band. The simulated and experimental performances are presented in this work where good agreement is obtained. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2624–2628, 2013
Radiated power enhancement of quadrupole source using metamaterials
Authors: Mitra Debasis , Paul Sandip , Bhattacharya Dhrubajyoti , Bhadra Chaudhuri Sekhar Ranjan
Published: August 2013

An investigation of radiated power enhancement of infinitesimal quadrupole source using metamaterial shell is presented. It has been demonstrated that a double negative shell surrounding the quadrupole can cancel both the self and mutual reactance within the quadrupole elements. Moreover, a uniform gain characteristic can be achieved over a wide range of shell thickness. The effects of loss, present in the metamaterial shell, are also taken into account for this investigation. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2620–2624, 2013
Design of a 2×2 tapered dielectric‐loaded helical antenna array for INMARSAT‐M satellite system
Authors: Manoochehri Omid , Abbasiniazare Seyyedpayam , Forooraghi Keyvan
Published: August 2013

In this paper, design and fabrication of an L‐band axial mode 2 × 2 tapered dielectric‐ loaded helical antenna array for international maritime satellite organization (INMARSAT)‐M mobile vehicles are presented. This array has compact size and light weight. By adding a tapered cylindrical dielectric resonator, for satellite communications, important parameters such as gain, side lobe level, impedance matching and axial ratio bandwidth have been improved simultaneously. This array has a gain of 15.1 dB, a radiation pattern with a side lobe level of –21 and a –3 dB axial ratio bandwidth is nearly 15%. These characteristics are suitable for INMARSAT‐M antennas. A good agreement between the simulated and measured results has been achieved. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2600–2604, 2013
Compact printed monopole antenna for ultra‐wideband application with dual band‐notched characteristic
Authors: Sarkar Manas , Dwari Santanu , Daniel Anitha
Published: August 2013

In this article, a compact ultrawideband (UWB) microstrip‐fed printed monopole antenna with dual band‐notched characteristics is proposed. The proposed design consists of a radiating patch with semielliptical shape and the modified ground plane with two bevels on the upper edge of the ground plane to cause the wideband from 3.1 to 10.6 GHz for UWB application. In addition, cutting two semicircular slots on the bottom edge of the ground plane, operating band is further extended above 10.6 GHz. The band notch at the two bands 3.4–3.6 GHz and 5.6–5.8 GHz is achieved using a pair of concentric annular slots with splits in them in opposite side. Fine tuning is possible with adjusting the length and radius of those slots. The antenna size is 24 × 34.6 mm and designed using FR4 substrate having εr = 4.4 and thickness of 0.8 mm. Design and optimizations have been carried out using HFSS v13.0 and there is good agreement with measured results. The proposed antenna exhibits a nearly omnidirectional radiation pattern in the H‐plane, and a dipole‐like radiation pattern in the E‐plane for the entire pass band. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2595–2600, 2013
Design and analysis of a meandered multiband antenna based on split ring resonator
Authors: Sharma Ashish , Gupta Surendra K. , Kanaujia Binod K. , Pandey Ganga P. , Sharma Manish
Published: August 2013

This article presents design and analysis of a novel compact circular patch microstrip antenna to be used for multiple services. The study is done on a circular patch antenna loaded with four slits which has a meandering effect on the surface currents along with a single unit cell of a split ring resonator (SRR) printed with copper on a substrate for the multiband operations. Circuit model of SRR configuration is also presented. The proposed antenna configuration is simulated and theoretically analyzed. The antenna is fabricated for best performance. The theoretical and simulated results are found to be in close agreement with measured results. Furthermore, parametric analysis is done by varying the height of SRR and gap width between the two SRR rings. Proposed configuration with a compactness of around 28%, and a broad beam width with high‐efficiency cover X‐band of microwave regime between 6 and 12 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2787–2795, 2013
Design of a compact wideband circularly polarized microstrip antenna
Authors: Liu Qiang , Liu Yuanan , Wu Yongle , Li Shulan , Yu Cuiping
Published: August 2013

abstract

A compact wideband feed network comprising a dual‐band Wilkinson power divider and a broadband 90° phase shifter is presented. Taking advantage of the coupled‐line section, the feed network achieves both compact circuit configuration and wideband performance. A compact wideband circularly polarized (CP) antenna using the wideband feed network achieves measured impedance bandwidth (|S11| ≤ –10 dB) of 65%, 3‐dB axial ratio bandwidth of 63%, and peak gain of 8.8 dBi. Above all, the proposed CP antenna features most compact size with the demensions of 0.64 λ0 × 0.64 λ0 × 0.054 λ0 and achieves the trade‐offs between the performance and the demension. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2531–2536, 2013
A novel multifrequency hybrid antenna
Authors: Bhattacharya (Mitra) Sriparna , Gupta Bhaskar
Published: August 2013

A hybrid multifrequency antenna is designed by using a cubic dielectric resonator antenna and coplanar wave guide (CPW) loop radiator. The dielectric resonator antenna (DRA) is also excited by the same CPW. The DRA in conjunction with the CPW loop generates multiple frequencies which may be controlled by optimizing the dimension of the DRA and the dimensions of the CPW slot. Six different resonant frequencies are observed between 2 and 7 GHz. The return loss, radiation pattern, and gain are measured for the antenna in all six different frequencies. The simulated and experimental results show good match. The proposed antenna can be used for mobile and wireless LAN communication. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2712–2715, 2013
Soft computing techniques on multiresonant antenna synthesis and analysis
Authors: Demircioglu Erdem , Sazlı Murat H. , İmeci Sehabeddin Taha , Sengul Orhan
Published: August 2013

The synthesis and analysis of a multiresonant microstrip patch antenna using soft computing techniques are presented. The multiresonance is obtained via attaching inverted L‐shaped stubs to the radiated edges of the single frequency patch antenna. The physical geometry of the proposed antenna is synthesized using adaptive‐neuro‐fuzzy inference systems and the calculated dimensions are applied to the artificial neural network for the analysis process. The return loss and phase of the scattering parameters are computed. The modeled antenna provides 95% accuracy and sufficient results compared with the simulation and measurement results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2643–2648, 2013
A 60 GHz transceiver for low power ad hoc networks
Authors: Loyez Christophe , Bocquet Michael , Rolland Nathalie
Published: August 2013

This article presents a low‐power consumption architecture of RF transceiver using impulse radio signals operating at 60 GHz. Both intrinsic features and related technologies of this operating frequency are detailed and the specific topology of this communication and geolocalization system is introduced. The performance of this low‐power consumption system is validated experimentally. The emitter exhibits an energy efficiency down to 10 pJ/bit and data rates up to 10 Mbps. Geolocalization ability of this 60 GHz system is also experimentally demonstrated with localization accuracy in the range of 40 cm. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2640–2643, 2013
Balanced BPF with wide upper stopband and wide common‐mode suppression response for WiMax applications
Authors: Lee Ching‐Her , Hsu Chung‐I.G. , Wen Pi‐Hung
Published: August 2013

This article presents a new balanced bandpass filter (BPF), which is designed using coupled stepped‐impedance slot‐line resonators (SISLRs) fed by microstrip feeding lines. The SISLRs are deployed symmetrically with respect to the plane of symmetry to achieve favorable differential‐mode (DM) response and high common‐mode (CM) rejection. For DM operation, the plane of symmetry is virtually grounded, and resonance can occur for each half SISLR. For CM operation, the resonator boundary along the plane of symmetry is open‐circuited, rendering the half SISLRs structure incomplete and hence, causing weak signal transmission. A prototype of the proposed balanced BPF was implemented, and good agreement was observed between simulated and measured results. The designed BPF has a measured minimum DM insertion loss of 1.13 dB in the passband of 3.38–3.72 GHz, in which the measured CM suppression is larger than 55.76 dB. In particular, the upper DM stopband with 20 dB rejection extends up to 21.05 GHz, and the CM suppression is larger than 26.5 dB in the whole displayed frequency range of 2–22 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2609–2611, 2013
A low‐consumption electronic system developed for a 10 km long all‐optical extension dedicated to sea floor observatories using power‐over‐fiber technology and SPI protocol
Authors: Frederic Audo , Veronique Quintard , Mikael Guegan , Andre Perennou , Yves Auffret
Published: August 2013

A 10‐km long extension using power‐over‐fiber technology and dedicated to sea floor observatories is presented with a particular focus on the electrical both ends units. We propose a solution using a serial peripheral interface 3 wires protocol for large range of low‐power sensors like hydrophones. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2562–2568, 2013
Mode discussion of the microstrip traveling antenna
Authors: Wang Chien‐Jen , Tai Yang
Published: August 2013

This work examines the resonant‐mode analysis of the microstrip traveling antenna (or calling the leaky‐wave antenna). Considering the traveling antenna as an open‐end structure, the antenna embodiment can be analyzed by utilizing the cavity‐mode analysis. In order to understand the resonant characteristics of the traveling antenna, we use two traditional traveling antennas with two different lengths. The corresponding relationship between the resonant modes for the short and long antennas is derived. The radiation mechanism of the antenna is also explained with aid of the equivalent magnetic current density. The antenna designers can predict the resonant modes of the traveling antenna without utilizing expensive EM simulation software. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2556–2562, 2013
Compact multi and wide‐bandwidth of printed inverted‐F antenna for wireless communication applications
Authors: Elsheakh Dalia
Published: August 2013

Compact multi and wide‐bandwidth printed inverted‐F antennas are proposed in this article. The proposed antennas are printed on commercial thin FR4 substrate with suitable antenna volume 20 × 50 × 1.6 mm3 to be easily integrated behind laptop screen. The printed‐inverted‐F antenna (IFA) achieved by combining L‐loaded printed‐IFA with two printed underneath radiators connected to the other side by vias. By adjusting stub via location, it may be obtained multi or wideband resonant antenna. These antennas are suitable for GSM 0.85/1.8 GHz, long‐term evolution wireless 1.5, 1.9, 2.1 GHz and from 2.5 to 2.7 GHz, and industrial, scientific, and medical 2.45 GHz. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2803–2808, 2013
Liquid crystal based Rotman lens antenna with switchable monopulse patterns
Authors: Christie Steven , Cahill Robert , Mitchell Neil , Munro Yvonne , Manabe Atsutaka
Published: August 2013

An electronically reconfigurable Rotman lens is described which generates multiple beams that can be switched from monopulse sum to difference radiation patterns when used in conjunction with a six element Vivaldi antenna array. This is achieved by exploiting the voltage‐dependent dielectric anisotropy property of nematic state liquid crystals to provide switched 0° and 180° phase shifts in the array feed lines. The viability of the concept is demonstrated by designing an antenna which exhibits dynamically reconfigurable monopulse radiation patterns over the frequency band 6–10 GHz. Measured and simulated results are shown to be in good agreement. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2721–2726, 2013
Millimeter‐wave CMOS lowpass and highpass filters with transmission zeros based on coupled‐line and transmission line
Authors: Tanii Kosei , Wada Koji , Makimoto Mitsuo , Igarashi Sadao , Fukui Kuniaki , Kobinata Kouichi
Published: August 2013

A millimeter‐wave lowpass and highpass filters are proposed by using a coupled‐line and a transmission line. Because these proposed filters have transmission zeros, the conditions of them are found by using even and odd modes analysis. Then, complementary metal oxide semiconductor technology is applied to the proposed filters. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2808–2813, 2013
A CPW‐fed hexagonal‐shape monopole‐like UWB antenna
Authors: Gautam A. K. , Chandel Richa , Kr Kanaujia Binod
Published: August 2013

A novel CPW‐fed hexagonal‐shape monopole‐like ultrawideband (UWB) antenna is proposed for UWB applications. The proposed antenna posses a method to minimize the monopole antenna by using a hexagonal shape over the conventional monopole patch antenna to lower the height of the antenna. The ground is vertically extended toward two sides of the single radiator. Therefore, the large space around the radiator that is usually wasted can be effectively saved. The antenna is practically fabricated and simulated. Measured results show a good agreement with simulated results. The prototype with very compact overall size of 25 × 23 × 1.6 mm3 achieves good impedance matching, stable radiation patterns, and constant group delay over an operating bandwidth of 2.71–12.61 GHz (9.9 GHz). © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2582–2587, 2013
A CPW‐fed wide‐slot antenna with reconfigurable notch bands for UWB and multi‐band communication applications
Authors: Li Yingsong , Li Wenxing , Mittra Raj
Published: August 2013

In this article, we present a compact wide‐slot antenna with reconfigurable notch bands, for ultra‐wideband (UWB) and multiband communication applications. The dual band‐notch characteristics are realized by using three open‐ended stubs inserted into the fork‐like radiating element, and the reconfigurable characteristics are achieved by integrating ideal switches in the stubs. By controlling the ON/OFF states of the ideal switches, the proposed antenna can function either as a UWB antenna with two notch‐bands, or a single notch‐band UWB antenna, or even a multiband antenna. The simulation and measurement results show that the proposed antenna is suitable for UWB as well as multiband communication systems. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2777–2782, 2013
A BiCMOS Ka‐band RF‐pulse former for short‐range high‐resolution radar and high‐data‐rate communication systems
Authors: Huynh Cuong , Nguyen Cam
Published: August 2013

An ultra‐low‐leakage RF‐pulse former capable of producing very narrow RF pulses with small rising and falling time for short‐range high‐resolution radar and high‐data‐rate communication systems is developed using 0.18‐µm BiCMOS technology. The narrow RF pulses are produced from a continuous‐wave RF signal by gating a high‐speed single‐pole single‐throw switch implemented with small gate‐resistors. The RF‐pulse former exhibits an extremely low RF leakage implementing the RF leaking suppression technique, in which the RF leaking signal is cancelled by combining with its replica using an active balun. In addition, the active balun also amplifies the gated RF pulses hence providing gain for the RF‐pulse former. A graphical analysis based on the insertion loss and isolation contours, enabling selection of the optimum sizes for transistors in the series‐shunt switches, is also presented. From 31 to 37.1 GHz, the designed RF‐pulse former exhibits −1.9 dB (loss) to 1.1 dB (gain) and 14.5–30‐dB input return loss. The output return loss is higher than 10 dB from 33 to 35.9 GHz. From 30 to 40 GHz, the isolation is higher than 40 dB and, especially at 34 GHz, the isolation reaches 70 dB. The rising and falling times were measured as 136 and 70 ps, respectively. Very narrow RF pulses of 200 ps have been generated. The RF‐pulse former consumes a 7.3 mA from a 1.8‐V power supply and occupies a chip area of 0.225 mm2. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2773–2777, 2013
Asymmetrical grounded CPW‐fed antenna for WLAN applications
Authors: Dinesh R. , Vinod V. K. T. , Sarin V. P. , Shameena V.A. , Mohanan P.
Published: August 2013

A novel compact asymmetrical grounded coplanar waveguide‐fed antenna for dual‐band operation is presented. The modified asymmetric ground and slit on the radiating element provides dual band covering 2.4 and 5.2 GHz WLAN operation. A prototype of proposed antenna has been fabricated and tested. The antenna offers omnidirectional radiation pattern at 2.4 GHz and directional radiation pattern at 5.2 GHz. The peculiarity of the design is that each band can be independently tuned by varying the current paths. The antenna has an overall dimension of 26.5 × 5.7 × 1.6 mm3 when printed on a substrate of relative permittivity 4.4. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2739–2741, 2013
Design of compact tri‐band bandpass filter using centrally loaded resonators
Authors: Chen Fu‐Chang , Qiu Jie‐Ming , Chu Qing‐Xin
Published: August 2013

Tri‐band bandpass filter using centrally loaded resonators is presented in this article. The triple‐passband characteristics are realized by properly controlling the lengths and impedances of the uniform impedance resonator and the stub. To illustrate the concept, two tri‐band filters are designed, fabricated, and measured. Simulated and measured results are found to be in good agreement with each other. The prototype of the tri‐band filters achieve insertion loss of 1.6, 1.9, and 1.9 dB at 2.4, 3.5, 5.8 GHz, 1.2, 1.3, and 1.3 dB at 1.57, 2.45, 5.2 GHz, respectively. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2695–2699, 2013
Dual‐band bandpass filter using multimode square ring loaded resonators
Authors: Liu Haiwen , Ren Baoping , Li Shen , Lei Jiuhuai
Published: August 2013

A novel microstrip dual‐band bandpass filter (BPF) with multimode square ring loaded resonators (SRLRs) is proposed in this article. The improved SRLR is loaded by a meander ring stub and a stepped‐impedance resonator for compactness to realize the dual‐band performances. Even‐ and odd‐mode method is applied to explain mode splitting characteristics. Moreover, another mode in the second passband is generated by adding a half‐wavelength U‐shaped resonator. This resonator also introduces cross‐coupling between feed lines so that an additional transmission zero is produced, which enhance the selectivity. The dual‐band BPF operating at 2.4 and 3.5 GHz for WLAN and WIMAX applications is designed and fabricated. Measurement results agree well with the simulated results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2692–2695, 2013
A compact dual‐band folded‐slot antenna for WLAN application
Authors: Long Zheng , Guangming Wang , Yajun Hu , Zhao Zhang
Published: August 2013

In this article, a coplanar waveguide ‐fed miniaturization folded‐slot antenna for wireless local area network application is proposed. The two operating bands are achieved by folded‐slot antenna with slot loading. The parametric analysis of the antenna is done by the available electromagnetic solver HFSS11. The proposed antenna is developed, and its measured characteristics are in good agreement with the simulated results. The measured impedance bandwidth for 10‐dB return loss at 2.4 and 5.5 GHz operating band are 90 MHz (2.40–2.49 GHz) and 950 MHz (5.1–6.05 GHz), respectively. Furthermore, the antenna has a simple planar structure and occupies a small size of about 28 × 30 mm2. The antenna also shows good radiation and stable antenna gains across the operating band. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2753–2756, 2013
Design of miniaturized branch‐line coupler based on novel spiral‐interdigital resonator cells
Authors: Guo‐Cheng Wu , Guang‐Ming Wang , Bo Sun , Ya‐Wei Wang
Published: August 2013

A miniaturized branch‐line coupler operated at 2.15 GHz, which is based on the novel spiral‐interdigital resonator cells, is proposed in this letter. The electromagnetic characteristics of the novel spiral‐interdigital resonator cell are analyzed by simulator and equivalent circuit model, and the results prove that it has a frequency with phase of −90° in the passband. Then, the proposed branch‐line coupler is designed, fabricated, and measured; the measured and simulated results are in good agreement, showing that this proposed branch‐line coupler has good electromagnetic performances. Moreover, the whole size of the proposed branch‐line coupler is 11.55 × 18.6 mm2, which is only 27.6% of the conventional one, and the miniaturization has realized effectively. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2750–2753, 2013
Aperture coupled BaTiO3 based dielectric resonator antenna with dual‐band
Authors: Oliveira Elder E. C. , D'Assunção Adaildo Gomes , Oliveira Joao B. L. , Cabral Alciney M. , Assis Pedro C. , Vieira Marcelo S.
Published: August 2013

A low profile and dual band rectangular dielectric resonator antenna (DRA) based on high permittivity BaTiO3 is proposed. The antenna main characteristics are investigated for wireless communication system applications at the frequency band from 6.0 to 8.0 GHz. The antenna design is performed using Ansoft HFSS through the finite element method. Antenna prototypes are built and measured on a vector network analyzer (R&S ZVB14 model) for comparison purpose. Agreement between simulated and measured results is observed. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2759–2763, 2013
A dual‐band array antenna using dome‐shaped radiating patches
Authors: Dewan Raimi , Rahim Sharul Kamal Abdul , Malek Fareq , Ausordin Siti Fatimah , Yusuf Abdulrahman Amuda , Azemi Saidatul Norlyana
Published: August 2013

A novel design of a dual‐band array antenna for Wireless Local Area Network and Worldwide Interoperability for Microwave Access applications is presented in this article. The antenna operates at 3.5 dBi (the lower band) and 5.8 GHz (the upper band), with gains of 7.8 and 5.5 dBi, respectively. The corresponding percentage bandwidths are 2.85 and 2.40%. The overall length of the feeding network was reduced significantly because the elements in the array are closer to each other, with a separation of less than λeff/4. There is good agreement between simulation and measurement results. The results of the surface current study also are presented. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2680–2686, 2013
A Q‐band 4‐bit active phase shifter using 0.13 μm CMOS technology
Authors: Kim Ji‐Hoon , Lee Jong‐Wook
Published: August 2013

A four‐bit phase shifter has been designed and fabricated for millimeter‐wave CMOS phase array systems. Instead of using the conventional approach in which lossy switches are used for different phase path selections, we realize phase shifting by summing two quadratures having variable amplitude. Phase shifting is performed in 22.5° steps by using two variable gain amplifiers optimized for a wide phase‐control range. The realized active phase shifter achieves the measured root‐mean‐square (rms) phase error of <11.5° over frequencies from 39 to 42 GHz. The power consumption of the active phase shifter is 238 mW from a 2.4 V supply voltage. A three‐stage cascode gain amplifier is also designed to improve the overall gain of the phase shifter. The gain amplifier achieves a peak gain of 11.5 dB at 39 GHz with power consumption of 53 mW. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2676–2680, 2013
ERRATUM: A miniaturized branch‐line coupler using triangular patch type artificial transmission line
Authors: Oh Song‐Yi , Hwang Hee‐Yong
Published: August 2013

Originally published Microwave Opt Technol Lett 55:1718–1721, 2013; © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2813, 2013
Rapid, Microwave‐Assisted, and One‐Pot Synthesis of Magnetic Palladium–CoFe2O4–Graphene Composite Nanosheets and Their Applications as Recyclable Catalysts
Authors: Lu Xiaofeng , Yang Liu , Bian Xiujie , Chao Danming , Wang Ce
Published: August 2013

Here, a microwave‐assisted approach has been demonstrated to rapidly prepare magnetic Pd–CoFe2O4–graphene (GE) composite nanosheets in ethylene glycol (EG) solvent. The generation of both Pd and CoFe2O4 nanoparticles is accompanied with the reduction process of graphene oxide (GO) by EG. The surface morphologies and chemical composition of the composite nanosheets are characterized by transmission electron microscopy (TEM), energy‐dispersive X‐ray spectrometer (EDS), powder X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) measurements. The as‐prepared Pd–CoFe2O4–GE composite nanosheets exhibit a remarkable catalytic activity towards the reduction of 4‐nitrophenol by sodium borohydride (NaBH4) at room temperature. The apparent kinetic rate constant (K app) of this catalytic reaction could reach about 11.0 × 10−3 s−1. Moreover, the CoFe2O4 component exhibits a magnetic property, which could make the Pd–CoFe2O4–GE composite nanocatalysts separated from the suspension system. The catalytic conversion of the 4‐nitrophenol to 4‐aminophenol could reach 87.2% after four cycles. This work presents a simple, rapid, and versatile method to fabricate both metal and spinel‐type complex oxides on GE nanosheets, providing a new opportunity for their applications in the recyclable catalytic reaction.
Successive, Seed‐Mediated Growth for the Synthesis of Single‐Crystal Gold Nanospheres with Uniform Diameters Controlled in the Range of 5–150 nm
Authors: Zheng Yiqun , Zhong Xiaolan , Li Zhiyuan , Xia Younan
Published: August 2013

A simple and robust route is described to the synthesis of single‐crystal Au nanospheres with diameters controlled in the range of 5 nm to 150 nm. The success of this synthesis relies on the use of single‐crystal Au spheres with different diameters as the seeds for successive growth and the use of a slow injection rate for the precursor to enable surface diffusion for the atoms added onto the surface of a seed. The diameters could be precisely controlled by varying the size and/or number of the seeds. The products exhibit excellent uniformity in terms of both size and shape and they are expected to find widespread use in a number of applications, including self‐assembly, fabrication of metallodielectric photonic crystals, plasmonics, and biomedical research.
Thermal stability of lysozyme as a function of ion concentration: A reappraisal of the relationship between the Hofmeister series and protein stability
Authors: Bye Jordan W. , Falconer Robert J.
Published: August 2013

Anion and cation effects on the structural stability of lysozyme were investigated using differential scanning calorimetry. At low concentrations (<5 mM) anions and cations alter the stability of lysozyme but they do not follow the Hofmeister (or inverse Hofmeister) series. At higher concentrations protein stabilization follows the well‐established Hofmeister series. Our hypothesis is that there are three mechanisms at work. At low concentrations the anions interact with charged side chains where the presence of the ion can alter the structural stability of the protein. At higher concentrations the low charge density anions perchlorate and iodide interact weakly with the protein. Their presence however reduces the Gibbs free energy required to hydrate the core of the protein that is exposed during unfolding therefore destabilizing the structure. At higher concentrations the high charge density anions phosphate and sulfate compete for water with the protein as it unfolds increasing the Gibbs free energy required to hydrate the newly exposed core of the protein therefore stabilizing the structure.
Genistein versus ICI 182, 780: An ally or enemy in metastatic progression of prostate cancer
Authors: Nakamura Hisae , Wang Yuwei , Xue Hui , Romanish Mark T. , Mager Dixie L. , Helgason Cheryl D. , Wang Yuzhuo
Published: August 2013

BACKGROUND

Androgen signalling through the androgen receptor (AR) plays a critical role in prostate cancer (PCa) initiation and progression. Estrogen in synergy with androgen is essential for cell growth of the normal and malignant prostate. However, the exact role that estrogen and the estrogen receptor play in prostate carcinogenesis remains unclear. We have previously demonstrated the metastasis‐promoting effect of an estrogen receptor beta (ERβ) agonist (genistein) in a patient‐derived PCa xenograft model mimicking localized and metastatic disease.

METHODS

To test the hypothesis that the tumor‐promoting activity of genistein was due to its estrogenic properties, we treated the xenograft‐bearing mice with genistein and an anti‐estrogen compound (ICI 182, 780) and compared the differential gene expression using microarrays.

RESULTS

Using a second xenograft model which was derived from another patient, we showed that genistein promoted disease progression in vivo and ICI 182, 780 inhibited metastatic spread. The microarray analysis revealed that the metallothionein (MT) gene family was differentially expressed in tumors treated by these compounds. Using qRT‐PCR, the differences in expression levels were validated in the metastatic and non‐metastatic LTL313 PCa xenograft tumor lines, both of which were originally derived from the same PCa patient.

CONCLUSIONS

Together our data provide evidence that genistein stimulates and ICI 182, 780 inhibits metastatic progression, suggesting that these effects may be mediated by ERβ signalling. Prostate 73:1747–1760, 2013. © 2013 Wiley Periodicals, Inc.
Opposite effects of tamoxifen on metabolic syndrome‐induced bladder and prostate alterations: A role for GPR30/GPER?
Authors: Comeglio P. , Morelli A. , Cellai I. , Vignozzi L. , Sarchielli E. , Filippi S. , Maneschi E. , Corcetto F. , Corno C. , Gacci M. , Vannelli G.B. , Maggi M.
Published: August 2013

BACKGROUND

BPH and LUTS have been associated to obesity, hypogonadism, and metabolic syndrome (MetS). MetS‐induced prostate and bladder alterations, including inflammation and tissue remodeling, have been related to a low‐testosterone and high‐estrogen milieu. In addition to ERs, GPR30/GPER is able to mediate several estrogenic non‐genomic actions.

METHODS

Supplementing a subgroup of MetS rabbits with tamoxifen, we analyzed the in vivo effects on MetS‐induced prostate and bladder alterations. The effects of selective ER/GPER ligands and GPER silencing on prostate inflammation were also studied in vitro using hBPH cells.

RESULTS

ERα, ERβ, and PR expression was upregulated in MetS bladder, where tamoxifen decreased ERα and PR expression, further stimulating ERβ. In addition, tamoxifen‐dosing decreased MetS‐induced overexpression of inflammatory and tissue remodeling genes. In prostate, sex steroid receptors, pro‐inflammatory and pro‐fibrotic genes were upregulated in MetS. However, tamoxifen did not affect them and even increased COX‐2. In hBPH cells, 17β‐estradiol increased IL‐8 secretion, an effect blunted by co‐treatment with GPER antagonist G15 but not by ER antagonist ICI 182,780, which further increased it. GPER agonist G1 dose‐dependently (IC50 = 1.6 nM) induced IL‐8 secretion. In vitro analysis demonstrated that GPER silencing reverted these stimulatory effects.

CONCLUSIONS

GPER can be considered the main mediator of estrogen action in prostate, whereas in bladder the mechanism appears to rely on ERα, as indicated by in vivo experiments with tamoxifen dosing. Limiting the effects of the MetS‐induced estrogen action via GPER could offer new perspectives in the management of BPH/LUTS, whereas tamoxifen dosing showed potential benefits in bladder. Prostate 74:10–28, 2014. © 2013 Wiley Periodicals, Inc.