Experimental Multiport Bicone Antenna

Frequenz ◽  
2013 ◽  
Vol 67 (1-2) ◽  
Author(s):  
Pekka Eskelinen ◽  
Juhana Ylinen
Keyword(s):  
Direction Finding ◽  
Air Gap ◽  
Outer Conductor ◽  
Coaxial Probes ◽  
Center Conductor ◽  
Fin Thickness

AbstractA practical, easily manufactured multiport bicone antenna suitable for many receiving tasks such as direction finding systems can be made by using sharp-edged metal fins on the feeding coax center conductor to provide a tapered transition and connection path to coaxial probes. This construction resembles an arrow's tail. Already four mutually orthogonal fins can give full 360 degree azimuth coverage with suitable −3 dB port pattern overlap. Five experimental constructions working at Ku and Ka bands, each with fractional bandwidths of 23 to 31 per cent, are shown with full dimensional details. Suitable fin tapering is close to the full air gap in the coax and fin thickness should be less than 1/16th of the outer conductor diameter.

scholarly journals Simulation of Temperature Distribution in Horizontal Fin Heat Sink CPU Processor Using Comsol Multiphysics and Proportional Control

2015 ◽  
Vol 1 (1) ◽  
pp. 1
Author(s):  
T.D. Sugiarto ◽  
R.F. Iskandar ◽  
Ismudiati Puri Handayani
Keyword(s):  
Temperature Distribution ◽  
Surface Area ◽  
Forced Convection ◽  
Heat Sink ◽  
Air Gap ◽  
Comsol Multiphysics ◽  
Convection Coefficient ◽  
Proportional Control ◽  
Fin Thickness ◽  
Heat Sink Design

This research is aimed to analyze and simulate the temperature distribution in heat sink CPU processor. The study analyzes the heat absorption from the heat source to the bottom of the heat sink, the conduction process, and the forced convection process. All processes are simulated with software Comsol Multiphysics 4.4 to obtain the optimal heat sink design. The simulation is performed by varying the number of fins, the fin thickness, the air gap between two fins, the fin surface area, and the convection coefficient. The optimal design is found for heat sink with 40 pieces fins, fin thickness of 0.4 mm, air gap of 2.4 mm, fin surface area of 9425 mm2, and the convection coefficient of 5.26 W/m2K. Further simulation shows that PID control improved the forced convection process. A proportional control (P) is reasonable enough to achieve a settled convection process. A settling temperature occurs at 241 s after heat is applied to the system. This is faster than non-controlled convection process which requires 1600 s instead. Additional integration and derivative controls will increase stability at later time.

Symmetric-pair antennas for beam steering, direction finding or isotropic-reception gain

1991 ◽  
Vol 138 (4) ◽  
pp. 368 ◽  
Author(s):  
R. Benjamin ◽  
W. Titze ◽  
P.V. Brennan ◽  
H.D. Griffiths
Keyword(s):  
Beam Steering ◽  
Direction Finding ◽  
Symmetric Pair

A novel analytical calculation of magnetic field in the slotted air gap of spoke-type permanent-magnet machines using conformal mapping

2020 ◽  
pp. 1-15
Author(s):  
Jianqi Li ◽  
Yu Zhou ◽  
Jianying Li
Keyword(s):  
Magnetic Field ◽  
Conformal Mapping ◽  
Permanent Magnet ◽  
Flux Density ◽  
Analytical Method ◽  
Electromotive Force ◽  
Analytical Calculation ◽  
Air Gap ◽  
Permanent Magnet Machines ◽  
Peak Value

This paper presented a novel analytical method for calculating magnetic field in the slotted air gap of spoke-type permanent-magnet machines using conformal mapping. Firstly, flux density without slots and complex relative air-gap permeance of slotted air gap are derived from conformal transformation separately. Secondly, they are combined in order to obtain normalized flux density taking account into the slots effect. The finite element (FE) results confirmed the validity of the analytical method for predicting magnetic field and back electromotive force (BEMF) in the slotted air gap of spoke-type permanent-magnet machines. In comparison with FE result, the analytical solution yields higher peak value of cogging torque.

Effects of contact gap on nondestructive evaluation using magnetic measurement for ferromagnetic steel

2020 ◽  
Vol 64 (1-4) ◽  
pp. 969-975
Author(s):  
Hiroaki Kikuchi ◽  
Yuki Sato
Keyword(s):  
Magnetic Flux ◽  
Nondestructive Evaluation ◽  
Effective Permeability ◽  
Magnetic Circuit ◽  
Magnetic Measurement ◽  
Air Gap ◽  
Motive Force ◽  
Hysteresis Curve ◽  
Evaluation Technique ◽  
Ferromagnetic Steel

We investigated effects of contact gap on magnetic nondestructive evaluation technique using a magnetic single-yoke probe. Firstly, we evaluated hysteresis curves and impedance related to permeability of the material measured by a single-yoke probe, when an air gap length between the probe and specimens changes. The hysteresis curve gradually inclines to the axis of the magneto-motive force and magneto-motive force at which the magnetic flux is 0 decreases with increasing the gap length. The effective permeability also decreases with increasing the gap thickness. The incremental of gap thickness increases the reluctance inside the magnetic circuit composed of the yoke, specimen and gap, which results in the reduction of flux applying to specimen.

The application of the on-board devices radio direction-finding in the navigation systems of drones

2016 ◽  
Vol 0 (15) ◽  
pp. 48-53
Author(s):  
A. A. Shpilka ◽  
A. Y. Myronchuk ◽  
A. O. Tkach ◽  
S. P. Overchuk ◽  
V. O. Katiuha ◽  
...  
Keyword(s):  
Direction Finding ◽  
Navigation Systems
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