The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Due to the large variability in human bodies characteristics, the main challenge to face to get an effective antenna for on-body clinical applications is to achieve a good robustness with respect to this variability (e.g., dielectric constant and geometry of the tissues). In this work we design a compact patch antenna which shows a significant robustness.
In magnetic resonance imaging (MRI), the electrical performance of the RF coil is critical to achieve sufficient signal to noise ratio (SNR). In this work, the variation of performance of a plane and a flexible coil over a saline and a humanlike phantom is proposed. In order to evaluate the RF sensitivity of these flexible devices, we performed both an electrical characterization of the coil performances...
A MoM analysis procedure for Artificial Magnetic Conductors, using equivalent magnetic currents is presented, and its advantages discussed for both patch-type and aperture-type AMC.A quite accurate equivalent circuit has been extracted from our MoM results, using a curve-fitting procedure.
The inductive assemblies with variable geometry have recently been proposed for potential electromagnetic (EM) energy harvesting utilization. Such inductors are capable of changing their initial geometry under the influence of some external force, collecting additional magnetic flux and producing increased induced voltage. In order to evaluate performance of such inductors, regarding increase of its...
This work focuses on the heat transfer dynamics in agricultural soils when exposed to microwave (MW) fields, in order to disinfect them and to eliminate dangerous organisms without using pesticides. The work managed with the design of a horn antenna, with fixed feeding power, to be used to irradiate the superficial layer of soils for a fixed depth. The soil was approximated using a transmission line...
Composites material made form Carbon NanoTubes have attracted much interest as shielding materials. A new model for the full-wave simulation of the shielding effectiveness is presented. The full-wave evaluation of that effectiveness is also discussed.
An evaluation of the present approach to the design of birdcage RF coils for RMI, based on periodic lumped circuit, has been performed. It appears that, for coils bigger than λ/6, a more accurate model is required, to reduce the trial-and-error tuning of the coil.
The proposed antenna works in close proximity of human tissues, so that in order to enlarge the bandwidth, the “hat-patch” configuration has been used. The antenna has been tested close to a four layer model of human breast showing a promising behavior.
An analysis of Electromagnetic Interference (EMI) between a Radio Frequency Identification (RFID) device and an Implantable Cardiac Defibrillator (ICD) is presented in this paper. In particular, the analysis focuses on the effects of EMI produced by an RFID reader on ICD operation. Thus, a brief overview of both ICD and RFID devices is presented at first. Subsequently, several experimental tests are...
In this paper evolutionary computation is applied to the synthesis of planar periodic EBG for dual frequency applications. We constrained our evolutionary design to the unit cell geometry and used a full-wave MoM to evaluate all individuals.
We present a frequency domain finite difference approach in curvilinear coordinates to the computation of the modes of elliptical ridged waveguides. The use of a elliptical mesh allows to avoid staircase approximations of the boundary, providing a very effective and accurate procedure.
In this work we present an application of the Particle Swarm Optimization algorithm to the design of ridge waveguides. The main requirements of a large bandwidth, and a good power handling capability has been both included, and different solution have been found, depending on the relative weights.
This paper presents a small truncated waveguide fed by a microstrip line through a transverse coupling slot for multi-band WLAN applications. The proposed radiating element allows to obtain a high radiated power, with a very low cross-polar component in the radiated field, with a −10 dB bandwidth that covers the required frequencies for multi-band WLAN applications (5.2/5.4/5.8 GHz).
This paper presents a wire antenna for multi-band WLAN application, designed using the Structure-Based Evolutionary Programming, and having a very simple geometry. The antenna has been analysed with NEC-2 during the evolutionary process, and the outcome of the procedure shows a very good performance, with a −10dB bandwidth that covers the required frequencies for multi-band WLAN applications (2.4/5...
This paper presents a wire antenna for multi-band WLAN applications, designed using the Structure-Based Evolutionary Programming, and having a very simple geometry. The antenna has been analysed with NEC-2 during the evolutionary process, and the outcome of the procedure shows a very good performance, with a −10dB bandwidth that covers the required frequencies for multi-band WLAN applications (2.4/5...
This paper presents a small truncated waveguide fed by a microstrip line through a transverse coupling slot for multi-band WLAN applications. The proposed radiating element allows to obtain a high radiated power, with a very low cross-polar component in the radiated field, with a −10 dB bandwidth that covers the required frequencies for multi-band WLAN applications (5.2/5.4/5.8 GHz).
Finite differences, i.e., the direct discretization of the vector eigenmodes equation, can be a very effective approach to the computation of waveguide modes, as long as the discretization grid matches exactly the grid boundary. We describe here the implementation of such approach for a circular waveguide, using a polar grid, both for TE and TM modes. The resulting matrix eigenvalue problems turns...
We describe here a Vector Finite Difference approach to the evaluation of waveguide eigenvalues and modes. The VFD is applied using a 2D cartesian grid, in the waveguide section. A suitable Taylor expansion of the vector mode function, allows to take exactly into account the boundary condition for a large class of waveguide. The FD approximation results in a constrained eigenvalue problem, that we...
The experimental validation is an important step in any measurement procedures development. In this paper, according to the absorber method, a meaningful set of experimental results for the evaluation of the reflectivity of materials in a Reverberating Chamber (RC) is shown in order to validate the attendant measurement procedure. Measurements on a frequency range between 1 to 18 GHz have been successfully...
A finite-difference technique to compute Eigenvalues and mode distribution of non standard waveguide (and aperture) is presented. It is based on a mixed mesh (cartesian-polar) to avoid discretization of curved edges, and is able to give an accuracy comparable to FEM techniques with a reduced computational burden.
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.