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APPLICATION NOTE
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GPS ANTENNA DESIGN
Global Positioning System is increasingly getting melt in our everyday life. In order to keep the GPS devices low-profile and portable, designers often resort to printed antennas. GPS applications use a very narrow bandwidth around 1.575 GHz, since they cannot afford any interference. For this purpose, in this example an HFWorks simulation is presented for a patch microstrip antenna operating at 1.575 GHz with a very narrow band. The dimension of the patch is almost 2*2 cm which is convenient to integration in a portabtle device.
The antenna simulation is performed in frequencies ranging from 1.5 GHz to 1.65 GHz to precisely visualize the behavior of the antenna around the intended frequency 1.575 GHz of the GPS application. Figure 2 shows that the return loss increases rapidly from 0.3 dB to above 20 dB at the desired frequency.
Figure 3 contains the radiation of the total electric field in linear and dB situated in the Phi=0 plane. In the Figure 4, a 3D plot of the radiated electric field in the linear format is shown.
Figure 4 - 3D plot of the radiated electric field in linear format
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Figure 1 - GPS antenna 3D structure
Figure 2 - Reflection coefficient at port 1
Figure 3 - Total radiated E field (in Linear and dB units) in Phi=0 plane
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3D FEM SIMULATION OF ELECTROMAGNETIC ACTUATOR WITH FERRO-FLUID
Linear electromagnetic actuators with solenoid type, are widely used in industrial applications. They are part of various electromagnetic devices based on different controlling mechanisms; they are used in electromagnetic valve actuation systems, fuel injection, exhaust gas recirculation systems, washing machines, etc. In order to develop an electromagnetic actuator with optimal actuation force, high reliability and low energy consumption, a new generation of actuators design has been developed with the addition of a Ferro-fluid in the working gap. Such type of fluid with an increased magnetic permeability could significantly reduce the magnetic reluctance of the actuator. This will result on a higher magnetic force generated by the actuator. Figure 5 shows cross section views of the simulated DC actuator.
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Figure 5 - Cross view of the 3D model
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During this simulation, the operational static characteristics are determined for actuator with Ferro-fluid (? >1) and without Ferro-fluid (?=1) in the working gap. Two models will be discussed: the first model with Linear Carbon Steel 12040 material (Core and plunger) with magnetic permeability ?=1000 while the second model has a nonlinear material.
Figures 6 a) and 6 b) show a cross section view of the magnetic flux density for a ferro-fluid with a relative permeability respectively equal to 1 and 5. The magnetic flux is higher in the case of permeability equal to 5. Figure 7 shows a cross section view of the magnetic flux density in the case of nonlinear material and a ferro-fluid with relative permeability equal to 50.
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Figure 6 - Flux density distribution in the case of linear material and ferro-fluid with relative permeability equal to a) 1 , b) 5
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Figure 7 - Flux density distribution in the case of nonlinear material and ferro-fluid with relative permeability equal to 50
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Figure 8 contains the curve of magnetic force produced by the actuator versus relative permeability of the ferro-fluid in the case of linear material (core and plunger). The force keeps increasing until reaching a constant value for a relative permeability higher than 20. In the Figure 9, the force curve in the case of nonlinear material shows a different behavior than in the Figure 8 when a linear material is used. The force augments until touching its highest value about 29N at a relative permeability near to 5, then it drops down to 5N at a relative permeability close to 50. The use of ferro-fluid helps to increase the force generated by a DC actuator in both case linear and nonlinear core material with a limited range of relative permeability in the second case.
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Figure 8 - Force versus ferro-fluid relative permeability in case of linear material
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Figure 9 - Force versus ferro-fluid relative permeability in case of nonlinear materia
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SCIENCE NEWS
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A New Way to See Magnetic Field
Although it might not be obvious, a material like lead has multiple magnetic fields, one inside and another on its surface. Until recently, researchers could confidently measure only surface fields. Now, in a recent Nature Communications paper, materials scientists in Germany describe a way to create detailed maps of the direction and strength of magnetic fields inside bulky materials like those used in electric engines and high-efficiency transformers.
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FIND US AT
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APEC 2019
CWIEME BERLIN 2019
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March 17-21, 2019, Anaheim, California , Booth #1163
May 21-23, 2019, Messe Berlin, Booth Hall 1_2, Stand C53
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