• Korean Journal of Materials Research
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• v.13 no.1
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• pp.48-52
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• 2003

The substituted yttrium iron garnet systems $Y_{ 3-x}$/Gd$_{x}$X$0.2_{0.2}$ $Fe_{4.8}$ $O _{12}$ (x = 0.2, 0.4, 0.6) have been investigated by means of X-ray diffraction, Mossbauer spectroscopy and SQUID. The X-ray diffraction patterns at room temperature confirm the samples to have a single phase of the garnet structure over the whole composition range. The lattice constants of all the samples linearly change with increasing x due to the size of substituted ions in the dodecahedral sites. $Y_{3-x}$ $Gd_{x}$ X$Fe_{4.8}$ $In_{0.2}$ $O_{12}$ system which $Y_{3-x}$ ions are substituted with Gd$^{ 3＋}$ ions, the Mossbauer spectrum consists of three Zeeman sextets at room temperature, one due to the $Fe^{3＋}$ ions on the octahedral(a-) sites and the others due to the $Fe^{3＋}$ ions on the tetrahedral(d-, d'-) sites, respectively. From the hysteresis loop measured by means of SQUID over the whole composition range, the saturation magnetization $M_{s}$ and magnetic moments $\mu_{ B}$ per unit cell have been obtained. The increment of Gd-ion content causes $M_{s}$ and $\mu_{B}$ decrease while the increment of In-ion content does not.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.4
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• pp.498-505
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• 1999

The ferrite device that has nonreciprocal characteristics has been used as various microwave components. In this paper, the spectral-domain method was used to analyze the characteristics of structure(strip line on multilayer structure with ferrite material) for which no paper has been published yet. It is assumed that an external dc magnetic field is applied perpendicular to the ground conductor. The propagation constant is calculated for each parameter and frequency. Also we considered convergence by increasing the number of basis functions and verified the numerical analysis results. From the results, we could confirm that as the thicknesses of YIG is increased, the cutoff region is widened and the propagation constant is decreased at the frequency of upper cutoff region. For a larger applied dc magnetic field, the frequency of cutoff region is found to be increased. Also the simulation results for strip line show that the cutoff region is widened and the propagation constant is larger than that of microstrip line.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.247-247
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• 2003

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1026-1033
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• 2007

This paper compared simulation characteristics on the design of center strip by structure simulator with manufacture of 2.6GHz non-reciprocal element. Secures condition that affect in PIMD and confirmed change value of PIMD by change of condition. Implemented non-reciprocal element shows more than 20dB isolation characteristic at center frequency(2,650MHz) and has 0.2dB insertion loss in overall 100MHz operating bandwidth. Return losses of input and output port are measured below -20dB. IMD of non-reciprocal element exhibited superior value when there were no gaps between internal components and when materials having identical substances were used, and it showed an improving tendency when the pressure was increased higher, however, in case of applying pressure higher than a certain level, it results in damages, etc. of the magnet inside and ferrite as well, so then the characteristics of IMD was rapidly increased along with decrease of frequency characteristics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.3 s.106
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• pp.229-238
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• 2006

In this paper, developed study about isolator that after design and optimizes center strip to use 3-D simulator. We use the factor about the change and propose simple mode of the simulation. Design strip line that center frequency is 1.85 GHz by software that use 3-D finite element method(FEM) and confirmed variable. Developed isolator were shown that more than isolation 25 dB, reflection loss has the more than 25 dB and insertion loss does not 0.2 dB. We could confirm that compare with simulation and manufacture sample propertied agrees more than 90 %.