Search results for "Coaxial"

Dual-band printed dipole antenna for Wi-Fi 802.11n applications

2010

A dual-band compact printed dipole antenna for Wi-Fi 802.11n applications in the 2.45 and 5.5 GHz bands is presented. The proposed antenna consists of two printed dipoles with the arms located onto both sides of the dielectric substrate and a bended stripline. This feed scheme makes easy the integration of the antenna with the electronic subsystem and avoids the radiation towards the device. For the design and optimisation, a specifically developed finite-difference time-domain based code is used. The antenna has then been fabricated, simulated and measured. The return losses highly match the Wi-Fi frequency specifications with a moderate gain (between 1 and 3 dBi) and efficiency better tha…

Test bench for coupling and shielding magnetic field

2016

This paper describes a test bench for training purposes, which uses a magnetic field generator to couple this magnetic field to a victim circuit. It can be very useful to test for magnetic susceptibility as well. The magnetic field generator consists of a board, which generates a variable current that flows into a printed circuit board with spiral tracks (noise generator). The victim circuit consists of a coaxial cable concentric with the spiral tracks and its generated magnetic field. The coaxial cable is part of a circuit which conducts a signal produced by a signal generator and a resistive load. In the paper three cases are studied. First, the transmitted signal from the signal generato…

Efficient FDTD analysis of discontinuities in a square coaxial waveguide

1996

A Novel Approach to the Characterization and Modelig of Microwave Transistor Packages

1994

A novel approach to the characterization and modeling of microwave transistor packages through dedicated VNA measurements is presented. By combining a multi-step partitioning method with the use of purposely realized - but technologically simple - "package style" test devices, the proposed technique permits to derive in a systematic manner an equivalent circuit for both the transistor package and the test-fixture mount employed for the characterization. Since it does not rely on the indirect, optimization-based, conventional extraction methods of the literature, nor on a simplified circuit structure for the overall parasitic fourport embedding the active device, it is able to provide a high…

Continuous-Flow Synthesis of Ni(0) Nanoparticles Using a Cone Channel Nozzle or a Micro Coaxial-Injection Mixer

2015

To synthesize nickel(0) nanoparticles by wet chemical reduction using hydrazine with an average size distribution below 100 nm, two different reactor concepts were developed. With a cone channel nozzle, the reactant solutions were sprayed into a batch for further processing and reduction at elevated temperatures. Another concept uses a micro-coaxial injection mixer connected to a heated tube to establish a fully continuously operating reactor. To shorten the time for reduction of the nickel, salt temperatures up to 180 °C are applied. To avoid uncontrolled residence time, the whole system was pressurized up to 80 bar. Approximately 80 L reactant solution, i.e., 1 kg nickel(0) nanoparticles,…

Active mixing inside double emulsion segments in continuous flow

2015

Fast mixing is essential for many microfluidic applications, especially for flow at low Reynolds numbers. A capillary tube-in-tube coaxial flow setup in combination with a glass microreactor was used to produce immiscible multiphase segments. These double emulsion segments are composed of an organic solvent as the shell (outer) phase and a completely fluorinated liquid (Fluorinert® FC-40) as the core (inner) phase. Due to the higher density of the core droplets, they are responsive to changing their position to the force of gravity (g-force). By gently shaking or jiggling the reactor, the core drop flows very fast in the direction of the g-field without leaving the shell organic phase segme…

Permanent magnet bottom-stirred swirling flow in coaxial shallow cylindrical containers

2021

Here, an original rotating permanent magnet (RPM) system placed coaxially with the liquid metal container is studied as an effective means of generating flow in shallow cylinders for potential application in aluminum metallurgy (e.g., for ladle stirring and metal dosing). The studied RPM system generates volume force with strong axial variation and force maximum near the radial midpoint. The numerical and experimental data show that, in the shallow cylinder case, the azimuthal velocity follows the force radial distribution. The resulting velocity maximum occurs near the radial midpoint, unlike in the traditional rotating magnetic field (RMF) stirrer systems, where the velocity maximum occur…

Full modal analysis of confocal coaxial elliptical waveguides

2000

An efficient method for analysing confocal coaxial elliptical waveguides is presented. Using elliptical coordinates, the differential Helmholtz equation is transformed into a linear matrix eigenvalue problem by means of the method of moments. The expressions of the vector mode functions for the full spectrum of these guides are constructed, including the TEM, TM and TE modes. The convergence of the method is very good, giving an efficient and accurate code. Comparisons with numerical results found in the technical literature validate the presented theory.

Coaxial Slot Antenna Design for Microwave Hyperthermia using Finite- Difference Time-Domain and Finite Element Method

2011

Hyperthermia also called thermal therapy or thermotherapy is a type of cancer treatment in which body tissue is exposed to high temperatures. Research has shown that high temperatures can damage and kill cancer cells, usually with minimal injury to normal tissues. Otherwise, ablation or high temperature hyperthermia, including lasers and the use of radiofrequency, microwaves, and high-intensity focused ultrasound, are gaining attention as an alternative to standard sur- gical therapies. The electromagnetic microwave irradiation applied to the tumor tissue causes water molecules to vibrate and rotate, resulting in tissue heating and subsequently cell death via thermal-induced protein denatur…

Mutual inductance of thick coils for arbitrary relative orientation and position

2017

An exact solution method has been developed recently which gives the mutual inductance of two thin cylindrical coils in terms of line integrals of a new kind of vector potential, induced by the primary coil, around the two circular edges of the secondary coil. This paper describes the extension of this method to thick coils, by wrapping two radial integrations around these line integrals. Results are presented for two pairs of conventional coils and a combination of a superconducting coil and a Bitter coil. Excellent agreement with existing results for non coaxial coils was obtained. The trade-off between accuracy and computing time is also examined.