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The numerical mode-matching (NMM) technique is a very efficient method to solve the electromagnetic problem of logging-while-drilling (LWD) sensors for geophysical prospecting. In this paper we present recent trends that have improved the numerical efficiency of the traditional NMM. Two NMM formulations are discussed here, with focus on its main relevant upgrades compared to previous approaches. We...
With the rapid growth of wireless systems, studies involving electromagnetic wave absorbers have attracted great attention from researchers. Their applications range from indoor systems to military applications. In parallel with this growth, increasing studies on Frequency Selective Surfaces (FSS) allow their filtering properties to be applicable in several systems, such as reflecting antennas, bandpass...
Analog Radio-over-Fiber (a-RoF) has gained increasing attention in the context of next-generation optical networks due to its spectral efficiency and lower deployment cost. However, electro-optical conversion of the information signal is delicate since the non-linear characteristic of the electro-optical modulator's transfer function causes inter-channel interference and poses a severe limitation...
In this work we propose a new electronic method for fiber Bragg grating (FBG) temperature compensation. This method uses a voltage-controlled gain amplifier (VCA) to compensation of temperature effects in a FBG sensing system that uses the edge filtering technique in the sensor's interrogator. We describe the technique and it application in a FBG vibration monitoring system. The results show a good...
This paper presents the design of an on-chip patch antenna on indium phosphide (InP) substrate for short-range wireless communication at 140 GHz. The antenna shows a simulated gain of 5.3 dBi with 23% bandwidth at 140 GHz and it can be used for either direct chip-to-chip communication or chip-level integration and packaging. In the transmission frequency band from 130 GHz to 150 GHz the estimated...
Long range ultrasonic testing approach is strategic due to its capability to inspect long distances and to detect incipient damage in rail transportation. The present work aims to verify the ability of a FBG sensor to measure ultrasonic guided waves in a subway rail sample. The results were compared with conventional acoustic detection using lead zirconate titanate (PZT) sensor in a 5-m rail sample...
In this paper the vibration analysis of a cantilever beam with viscoelastic neutralizer using fiber Bragg gratings (FBG) is presented. The optimal design, of the neutralizer, is achieved through a robust methodology developed by the Research Group on Vibrations and Sound in Mechanical Systems (GVIBS) at Federal University of Paraná (UFPR). Such methodology uses the Finite Element Method (FEM) to obtain...
The work presents a new proposition of an integrated optical device applicable as optical magnetometer. The studies of an optical waveguide formed by thermally induced static stress (ISS) and modulation achieved by magnetostriction of a TbCo2 thin film over Bismuth Germanate (BGO) are shown. The magnetooptical effect and the modal optical analyses were investigated for the optical modulation purpose...
A combination of asymptotic and rigorous methods is used to compute the radar cross section of an aircraft with engine inlets that include fan blades. The engine inlet and the blades are solved rigorously with an integral-equation method while the aircraft is analyzed with an asymptotic method. A two-step process is proposed that is both accurate and fast.
The design of an active integrated antenna (AIA) front-end circuit using the ATF-34143 field effect transistor (FET) in a minimum noise figure (NF) condition for GPS application is presented. Both RF and DC bias circuits are calculated for a co-designed probe fed circularly polarized rectangular microstrip antenna (CPRMA). To optimize performance a source inductance was added and tuned using a procedure...
We present the concept and design of a hybrid integrated widely tunable III-V-on-silicon ring laser with 80 nm tuning range by means of theoretical investigation. Laser spontaneous emission is provided by two gain chips, one for the C band and the other for the L band. Gain chip sections are duplexed into the silicon photonic passive cavity using a lattice filter. Wavelength tunability is proposed...
This work presents an analytical formalism for magnetooptic five-layered planar waveguides, which can be used as a fast resource to assist in the design of nonreciprocal optical couplers. The methodology was implemented in a GNU Octave program code and results are shown for both forward and backward guided propagation.
This work reports the design and prototyping of a 100 Gbit/s OTN 40 nm test chip, manufactured as a test vehicle strategy for an OTN processor device under development at CPqD for the Brazilian telecom industry. The main issues related to the integration of third-party silicon intellectual property solutions are covered, together with the evaluation environment where the test chip was successfully...
We present an analysis of the optical detection of two-dimensional vibration waves using two interferometric systems: a point-scanning heterodyne interferometer by optical reinjection (Laser Optical Feedback Imaging — LOFI) and a full-field stroboscopic Mach-Zehnder interferometer. We compare the spatial (resolution, sensitivity) and temporal (resolution, speed, bandwidth) performances for both vibrometers...
A self-calibration noniterative technique for determination of the optical constants and thickness of lossless materials using only three reflection measurements is proposed. A generalized model is derived based on the reflection measurements. For validation, two different samples (Si and GaAs samples) are considered for extraction of their optical parameters and thicknesses by using a numerical full...
We present the ultrashort pulse generation of sub-300 fs from a mode-locked Erbium doped fiber laser by using spin-coated graphene oxide and reduced graphene oxide saturable absorbers deposited onto polished surface of D-shaped optical fibers.
This paper presents in-situ evaluations comparing the EMF exposure associated with a BTS installed in the vicinity of an apartment, WLAN device and baby monitor in a typical scenario. The results show that under certain circumstances the exposure in the latter cases can be higher than the former.
This paper presents a full three-dimensional carpet cloak design, whose invisibility is independent of the incident wave direction. The device is developed with transformation optics and three-dimensional quasi-conformal coordinate transformation, which is obtained through parametrization and numerical optimization. The anisotropy reduction was sufficient to consider the medium as isotropic and to...
In this paper, we propose an approach to separate the temperature and strain information in a single fiber BOTDA system. The basis of this method is a mathematical theory to invert non-square matrices, called as Moore-Penrose pseudo-inverse. The system was tested both theoretically and experimentally in order to compare the use of a single optical band used to make a multi-wavelength measurement with...
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