pinecone/core-2020-05-10-deduplication huggingface dataset:
The resonant behavior of the fibonacci fractal tree antennas

An investigation of a novel fractal tree antenna with the application to two different geometries is presented. The antenna is designed by using the special Fibonacci number sequence which leads to nonuniform branch length ratios to form the fractal tree. This new approach gives better performance, especially in the miniaturization of the antenna, when compared with the conventional designs. The results obtained from the experiments are also compared with the computed ones and there is a very good agreement between the numerical and measured data
Design of coupling structures for groove guide resonators

Three different coupling structures for a groove guide resonator operating at 10 GHz are investigated. First, propagatable modes are determined analytically. Then, the efficiency of the coupling structures is investigated by means of the method of moments and measurements. Finally, a groove guide resonator is designed and the resonance spectrum for each coupling structure is computed numerically, applying the finite-difference time-domain method. Numerical results are compared with experimental measurements. There is good agreement between the measured and simulated data.TÜBİTA
Impedance matching wilkinson power dividers in 0.35μm SiGe BiCMOS technology

This paper presents two miniature Impedance Matching Wilkinson Power Divider\ud
circuits in 0.35μm SiGe BiCMOS technology for on-chip power combining techniques for WLAN applications. The Impedance Matching Wilkinson Power Divider circuits are used as splitter/combiner for a 5.2 GHz fully integrated class-A mode combined power amplifier. The splitter and combiner are designed to match the input and output impedances of the amplifier,\ud
respectively, so that no additional impedance matching is needed. Two fabricated impedance matching Wilkinson power divider circuits (splitter and combiner) have insertion losses better than 1.4dB, return losses less than -13dB and port-to-port isolation > 12 dB at 5.2GHz
An experimental investigation of multisolitons using an erbium doped fiber amplifier and a fiber optic ring resonator

We have successfully generated the mutisoliton pulses using a Gaussian pulse in a fiber optic ring resonator incorporating an erbium-doped fiber (EDF) and a semiconductor optical amplifiers (SOAs). The multisoliton memory time within the system is also measured. Initially, the Gaussian input pulse is pumped and amplified through the EDF and the SOAs, respectively. The suitable experimental values, such as drive current, coupling power, and the fiber ring radius, are arranged to generate the multisoliton pulses. In application, the wider multisoliton band can be generated by adjusting the suitable system parameters. Results obtained have shown that the multisoliton with a free spectrum range and spectrum width of 2.4 and 0.96 nm is achieved. The memory time and the maximum soliton output of 15 min and of 5.94 dBm, respectively, are noted
Automated design of microwave discrete tuning differential capacitance circuits in Si-integrated technologies

A genetic algorithm used to design radio-frequency
binary-weighted differential switched capacitor arrays (RFDSCAs) is
presented in this article. The algorithm provides a set of circuits all
having the same maximum performance. This article also describes the
design, implementation, and measurements results of a 0.25 lm
BiCMOS 3-bit RFDSCA. The experimental results show that the circuit
presents the expected performance up to 40 GHz. The similarity between
the evolutionary solutions, circuit simulations, and measured results
indicates that the genetic synthesis method is a very useful tool for
designing optimum performance RFDSCAs
Ultra-wideband GCPW-MS-GCPW driven electrode for low cost and wide range application electro-optics modulators

International audienceElectra-optic modulators are key components in high bit-rate optical transmissions. Decreasing the manufacturing cost without damage on performances is one of the most challenging issues for such components. We demonstrate that the electro-optic modulators based on Polymer are compatible with high bandwidth requirements. Indeed, according to the results obtained by numerical simulation and partly validated by experiments, with the via-free GCPW-MS-GCPW electrodes proposed and analyzed in this article. the (400 MHz-67 GHz) bandwidth is achievable with electro-optic modulators based on suitable polymers. These encouraging results are very useful for low-cost mass production of polymer-based electro-optic modulators for a wide range of applications: digital and analogue high bit-rate transmissions
Performance of microstrip patch antenna on a reinforced carbon fiber composite ground plane

Using mass-produced multiwall carbon nanotubes (MWCNTs) from different providers, we have fabricated nanocomposites with high and nearly constant shielding effectiveness (SE) over a wide frequency range up to 26.5 GHz. The MWCNT weight fraction and sample thickness were lower than 10% and 2 mm, respectively. The fabrication process and percolation curves are described. A high dc conductivity of 239.1 S/m was achieved at an MWCNT loading of only 8% by weight. The effect of aspect ratio on shielding performance is addressed. By comparing the measured SE of the composite with predictions from a model of the measurement setup using Microwave Studio, the effective conductivity of the nanocomposite was determined. Since the thickness is very important for shielding analysis, the SE/unit thickness diagram was calculated by using the effective parameters of samples. The results were verified experimentally by measuring the SE of samples with different thicknesses
Branch line coupler using hybrid t-model structure

A reduced size branch line coupler (BLC), which does not use bonding wires, lumped elements, or via holes, is reported in this article. The technique presented uses T-model approach, which is a combination of low-impedance and high-impedance quarter wave transmission lines for realizing the proposed structure. The coupler's operating frequency bandwidth is between 2.1 and 2.67 GHz, and its size has been reduced by almost 75.31% compared with the conventional BLC. The S-parameters and the phase difference between the output ports are simulated using CST microwave studio, and the simulation results have been compared with the measurements. The BLC has been designed to operate at 2.5 GHz and fabricated on flame resistance board (FR4 Board). The study shows that there is good agreement between the simulated and measured results. The proposed coupler has promising potentials for beam-forming network applications such as butler matrix due to its smaller siz
Performance analysis of pure paraffin Wax as RFID tag substrate

The article presents an investigation of the performance of the Paraplast, a kind of pure paraffin wax, used as a substrate of RFID tag antennas operating at UHF RFID band. To achieve this purpose, two similar RFID tag antennas with same dimensions have been simulated, fabricated and tested. These include a simple dipole tag on a Rogers RT/Duroid 5880 substrate and on pure paraffin substrate. Because of the relatively close dielectric constant values, paraffin substrate is compared with Duroid RT5880. Paraffin wax can be considered as a low cost and low loss substrate. The main purpose in the future will be using paraffin as a passive temperature sensor, by exploiting the changes in molecular structure, volume and dielectric properties with temperature, especially near its melting poin
Reconfigurable microstrip patch antenna for WLAN software defined radio applications

A reconfigurable microstrip patch antenna with radiofrequency (RF) pin diode switches is implemented for dual band of 2.4 and 5.6 GHz WLAN software defined radio (SDR) applications.For the dual band SDR system, the use of a single antenna with a wide bandwidth to cover both of the bands can be limiting for low power level signal applications due to wideband noise as well as changing radiation pattern at different frequencies. A reconfigurable nested microstrip patch antenna is designed on a Rogers 5880 RT/DUROID substrate which is fed by a coaxial probe from the back side of the grounded substrate. RF switching circuitry involves four RF pin diodes at each side of the inner patch. The dual bands of 2.4 and 5.6 GHz frequency operation can be simply obtained by switching the PIN diodes on and off. The antenna is well matched and achieves similar to 7 dBi gain at both frequency bands. Simulation and measurement results show that the nested patch antenna is suitable for dual band WLAN SDR applications
Dual-grid multiresolution technique for electrically large BoR-FDTD simulation

The dual-grid (DG) technique is implemented in the
body-of-revolution FDTD algorithm (BoR-FDTD) for the fast analysis of
large rotationally symmetric antennas. The proposed technique combines
two BoR-FDTD simulations performed successively with fine and coarse
mesh schemes, respectively. First, all excitation sources are analyzed
locally with a fine mesh resolution and the near-field distributions are
saved. Second, the whole problem (feeds and scatterers) is modeled
using a coarser mesh where the computational domain is excited by the
equivalent sources stored at the first stage. The continuity between these
two simulations is guarantied by means of linear field interpolation or
sampling (in space and time) and total/scattered field formulation. The
relevance of the proposed technique is demonstrated through the
analysis of a 60 x k0 parabolic antenna system illuminated by an
electromagnetic band gap feed. The DG technique is found to be
accurate and faster than the classical BoR-FDTD approach. Our results
also show that significant savings are obtained in terms of computation
time and memory. The DG-BoR-FDTD strategy is considered as a
powerful and flexible approach to analyze the influence of the
surrounding environments without having to repeat the expensive part of
the simulation
Manipulating microsized coupling gaps for reconfigurable antenna applications

This article was published in the journal Microwave and Optical Technology Letters [© Wiley Periodicals inc.]. The definitive version is available at: http://onlinelibrary.wiley.com/doi/10.1002/mop.27059/abstractSynthetically arranged microlines (width ≤ 1mm) have been considered for antennas and radiating structures at microwave frequencies. Finite-difference time-domain simulations show how the electrical size of the structure and multiple resonances can be controlled by carefully introducing microsized gaps
In-axis reception by polarization discrimination in a modulating-retroreflector-based free-space optical communication link

A new optical configuration is proposed for ground stations designed to receive information from modulating-retroreflector-based terminals in a free-space optical communication link. This configuration is based on the polarization discrimination of the ground station laser sent to the remote terminal. It achieves the optimal usage of the laser power, which is a key parameter in modulating-retroreflector-based links. A simulation has been made in order to model the system in terms of power losses and states of polarization and an experimental setup has been implemented to verify the validity of the simulation. A gain of over 6 dB has been measured using the new setup compared with a simple trajectory discrimination setup, achieving a very good agreement with the prediction.Publicad
Phase noise analysis for a mm-wave VCO configuration

The letter highlights the importance of modelling the phase noise of an oscillator using the impulse
sensitivity function. A Colpitts oscillator in the common collector configuration is analyzed to obtain an expression
for its phase noise. The oscillator design is thus optimized for phase noise with respect to process and design
parameters. The fabricated voltage controlled oscillator at an oscillating frequency of 52.8 GHz has a measured
phase noise of -98.9 dBc/Hz at 1 MHz offset.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1098-2760hb201
Indoor positioning based on global positioning system signals

The Global Positioning System (GPS) is highly reliable and accurate when used outdoors.However, in indoor environments, due to the additional signal loss incurred by the walls of the buildings, the detection and decoding of GPS signals becomes a difficult task. As a solution to the indoor area coverage problem, an indoor positioning system based on GPS repeaters and a modified positioning algorithm is proposed, designed, and tested. A prototype indoor positioning system for 1D/2D positioning is built using directional GPS antennas and low-noise amplifiers (LNA). The modified positioning algorithm is used for the real time processing of captured live GPS data. All the system components are integrated and positioning is obtained for the evaluation of the system performance. Results of the experiments show that the proposed system can be used for indoor positioning in locations where there is no GPS signal reception. The proposed system facilitates the continuation of GPS services indoors with hardware additions to the buildings and only a software update to a standard GPS receiver
Effective dielectric constant of top grounded coplanar waveguide on liquid crystal superstrate

The effective dielectric constant of the top grounded coplanar waveguide with a liquid crystal (LC) superstrate for phase shifting applications is investigated in the frequency range of 30-60 GHz. Two nematic LC mixtures, namely E7 and MDA-00-3506, are used as the superstrate. The measurements show that MDA-00-3506 offers higher values of phase shift per millimeter than its E7 counterpart. In particular, the MDA-00-3506 provides 3.14°/mm, whereas E7 gives 2.79°/mm at 60 GHz. The results of the dielectric constants from measurement and computer modeling are found to agree to within 5%. For the modeling, a comprehensive finite element package predicting the local alignment of LC molecules and effective dielectric constant at different bias voltages and frequencies are used. Copyright © 2013 Wiley Periodicals, Inc
Highly linear microstrip wideband bandpass filter with switchable notched band for wireless applications

This is the peer reviewed version of the following article: RABBI, K. ... et al., 2013. Highly linear microstrip wideband bandpass filter with switchable notched band for wireless applications. Microwave and Optical Technology Letters, 55 (6), pp.1331-1335, which has been published in final form at: http://dx.doi.org/10.1002/mop.27585. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.This article presents a highly linear reconfigurable bandpass filter embedded with a switchable notch structure to get a band-notched characteristic at a specified frequency.A single PIN diode (BAP65-02) is used for the purpose of switching the notch. An optical switch, comprised of a silicon dice activated using near infrared light is also investigated as an alternative to the PIN diode. While the PIN diode or the optical switch is in the ON state this reconfigurable filter behaves as a bandpass filter with a notch at 2.4 GHz in order to reject WLAN interference while a full band response is obtained in the OFF state. The proposed filter is able to achieve good linearity using PIN diode with IIP3 of 47 dBm and there is no significant loss. A prototype is fabricated, and measured results are compared to simulations. A good agreement has been achieved between simulated and measured results
Pseudo-elliptic function bandstop filter with shunt foster sections

Filters with transmission zeros in the stopband have been shown to have superior rates of cutoff. Conventional Cauer filters give excellent performance but are relatively large and not always practically realizable. In this article, the design of a pseudo-elliptic bandstop filter which employs only shunt Foster sections and unit elements is presented. The filter is of the same size as a Chebyshev filter of the same order, but has a performance comparable to a Cauer filter.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1098-2760hb201
Transmission line filters with harmonic parallel foster sections

Conventional wideband bandstop filters use Cauer prototypes, but become nonrealizable with Kuroda–Levy transforms for bandwidths of 150% or more. Transmission line filters with harmonic stubs have been shown to be realizable at these bandwidths, but have limited performance ranges due to the fixed positions of the transmission zeros. In this article, two structures that use shunt Foster resonators that enable the shift of the transmission zeros are described. Simulated and measured properties show that greatly improved performance can be realized while not adding to the complexity of the structurehttp://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1098-2760hb201
Microwave Tunable Notch Filter Based on Liquid Crystal Using Spiral Spurline Technology

In this article, the design, fabrication, and characterization of a tunable microwave notch filter based on liquid crystal (LC) using inverted-microstrip technology is presented. A spiral spurline structure is used because of its good performance as a single-resonator notch filter. Based on the LC dielectric anisotropy, a voltage-controlled rejection frequency of the filter is achieved, ranging from 3.40 to 3.75 GHz, which means that the tuning range relative to the central rejection frequency is about 10%. At the same time, this device exhibits negative group delay around the rejection frequency and the measured values throughout the tuning frequency range are presented.J. A. and M.M.S.L. acknowledge funding support from the Spanish Ministerio de Economia y Competitividad through project FIS2012-39158-C02-02. J. T., C. M., V. U. and J. M. S. P. thank funding support from the Spanish Ministerio de Economia y Competitividad (grant no. TEC2009–13991-C02-01) and Comunidad de Madrid (grant no. FACTOTEM S2009/ESP/1781).Publicad
A 180° tunable analog phase shifter based on a single all-pass unit cell

A 180 TUNABLE ANALOG PHASE SHIFTER BASED ON A SINGLE ALL-PASS UNIT CELL, K. Khoder, A. P erennec, and M. Le Roy, copyright 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2915-2918, 2013; View this article online at wileyonlinelibrary.com. The definitive version is available at www3.interscience.wiley.comInternational audienceThis article describes an analog phase shifter able to provide a continuously tunable phase shift up to 180 by using a single allpass unit cell. The proposed topology is compact and easy to implement, and brings an interesting compromise between phase variation, insertion and return losses. Indeed, for a 7.5:1 tuning ratio of varactor capacitance, a phase shift variation of more than 186 is obtained from 6 to 7GHz with a maximum insertion loss of 1.8 dB. The 105 /dB resulting Figure-of-Merit is thus among the best in distributed approaches with varactors
Linearity improvement analysis for PAs at mm-wave frequencies

This article presents an adaptive predistortion (APD) linearization
technique to improve the linearity of millimeter-wave power
amplifiers (PAs), specifically at 60 GHz. The PA and the APD were
designed using the 0.13 mm SiGe BiCMOS process. The predistortion is
applied to the PA by varying the gain of the PA through its variable
gain amplifier. The PA achieves a PSAT of 11.97 dBm and IP1 dB of
210 dBm. After linearization the PA has an improved IP1 dB of 26
dBm. This linearization technique results in an optimum intermodulation
distortion 3rd reduction of 10 dB.http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1098-2760hb2014ai201
Common-mode suppressed differential bandpass filter based on open complementary split ring resonators fabricated in microstrip technology without ground plane etching

A differential (or balanced) bandpass filter based on open complementary split ring resonators (OCSRRs) coupled through admittance inverters is presented in this article. Pairs of OCSRRs are symmet- rically placed in a mirror configuration between the strips of the differential line and are modeled by means of two series connected parallel resonators. For the differential (odd) mode, there is a virtual ground at the connecting plane between the OCSRR pairs, and the structure is roughly described by the canonical model of a bandpass filter, consisting of a cascade of shunt resonators coupled through admittance inverters. It is demonstrated that, through a proper design of the OCSRR stages, the common mode noise in the vicinity of the differential filter pass band can be efficiently suppressed. Due to the differential mode operation of the filter, it is not necessary to incorporate metallic vias to ground the OCSRRs. Moreover, as compared to other differential filters based on OCSRRs, defected ground structures are not present in the proposed filters. To illustrate the potential of the approach, two balanced bandpass filters are designed, fabricated, and characterized
Pattern reconfigurable patch array for 2.4 GHz WLAN systems

In this project, a pattern reconfigurable simple two patch array antenna has been designed and implemented to operate at a fixed frequency of 2.4 GHz for beam scanning purpose. Proposed antenna operates at three different modes in which the radiation pattern steers 0 degrees, +/-30 degrees with respect to the antenna broadside. In this article, a different approach has been taken to implement the reconfigurable antenna which is very simple and cost effective compared to previous works. For this, a SP3 RF switch is used to steer the radiation pattern by applying phase difference between the two antenna elements. A reconfigurable patch array is designed on a Rogers 5880 RT/DUROID substrate in which antenna element is fed in inset configuration. Measured and simulated results are well matched but with some minor deviations. Designed antenna array has a gain of 9 dBi in broadside and the gain drops to 7.5 dB when the beam is rotated by either +/-30 degrees. Pattern reconfigurable antenna can be used in wireless communication systems, where antenna pattern needs to be aligned with strongest signal sources or when the antenna needs to be kept away from noisy environments or interfering signals
Bandpass filter with stepped impedance subharmonic stubs

Structures with shunt stubs in a subharmonic ratio that realize bandpass performance have limited application due to the inherent problem of fixed transmission zero positions in the stopband. By application of the principle of splitting, the subharmonic stubs into cascades of transmission line sections, structures can be realized that have transmission zeros at arbitrary positions. A bandpass filter employing stepped impedance stubs is developed, and it is shown that moderate bandwidth can be achieved.http://onlinelibrary.wiley.comjournal/10.1002/(ISSN)1098-27602015-12-30hj201
SIW based interdigital bandpass filter with harmonic suppression

Cataloged from PDF version of article.A novel configuration of interdigital bandpass filter based on the substrate integrated waveguide (SIW) technology is proposed. In addition to the interdigital resonators in SIW that determine the main response/characteristics of the filter, narrowing the width of the SIW at the center of the filter and additional vias at its input and output parts act as two additional control mechanisms to achieve the desired filter response. Moreover, dumbbells are etched to the ground side of the microstrip feeding sections at both ends of the filter to improve its harmonic suppression. A prototype filter is designed and fabricated for verification. The measured results are in good agreement with the simulations, and the filter exhibits very good harmonic suppression. (c) 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:66-69, 201