• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.7
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• pp.43-50
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• 1995

In this paper, the variational method are used for the filter analysis methods and a CAD program for the design of the waveguide low-loss bandpass filters using inductive window structures for the VSAT(Very Small Aperture Terminal) system has been developed based on the passband correction method combined with fiter synthesis procedures. Using the developed CAD program, 0.01dB equi-ripple chebyshev type 6-section bandpass filters which are sued in the VSAT system operating nationally are designed for the purpose of the Down-link of 12.75~13.25GHz and the Up-link of 14.0~14.5GHz, fabricated and mesured. The measured results are good agreement woth the theoretical resuls.

• Journal of the Korean Institute of Telematics and Electronics
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• v.6 no.1
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• pp.1-11
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• 1969

Reactor power frequency spectrum measurements at various power levela-OW, 1KW, 50KW, 100KW were made with TRIGA-MARK-II. An ion chamber was exposed to reactor flux, and the fluctions in its output current were analyed in a tunable bandpass filter to get the frequency spectrum of these fluctuation. The measured frequency spectrum of pile determined the modules of modules of zero power transfer function and indicated a prompt neutron mean life time of (7.90$\pm$1.62)X10 sec based on effective delayed neutron faction of 0.0075. The absolute value of reactor power obtained by noise analysis agreed within 5% with the power meter indication at the power below 10Kw.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.31B no.12
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• pp.81-90
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• 1994

This paper proposes a motphological fast reconstructive filter (FRF) using up/down sampling techniques for reconstructive opening and closing, and a parallel structure for fast multiresolution decomposition. Compuer simulation shows that, compared with the conventional RF, the proposed FRF can reduce the processing time up to 8 times while it maintains a similar performance in reconstructed shapes. Further reduction in the decomposition time achieved by the paralellized algorithm combined with the FRF, which can be applied in areas such as defect detection, image segmentation, pattern recognition, etc.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.4
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• pp.84-91
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• 1996

Input filter for satellite communication transponder is the interface between the antenna and the receiver. It is used to provide the selection of the uplink signals with minimum insertion loss and to prevent downlink signals form reaching the LNA. This paper is intended to provide a description of the input filter for KOREASAT communication transponder. Included are description for the electrical and mechanical design and the requirments of environmental test. In expecting the electrical performine the optimum electrical configuration ot meet all requirements are performed. Mechanical requirements are charactersed by several constraints for weight, size of the filter and its type of input output interface. The standardized environmental tests are performed to confirm satisfactory performance of the filter with respect to the requirements of vibration and thermal vacuum shocks.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.4
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• pp.98-105
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• 1996

The design method of 85 GHz-115 GHz band single side-band filter using the principle of martin-puplett inteferometer is described. It has been designed by this method and also manufactured and tested. From the test results, not only the ratio of image singal rejection of 19 dB is obtained, but also the theoretical and experimental results of center frequency of pass-band and rejection-band show the validity of the theory. This manufactured filter was installed on 100GHz band SiS (superconductor insulator superconductor ) receiver for observing cosmic radio waves and tested. We found that this filter can be used a single side-band as well as double side-band mode. The design method which is presented in this paper can be used a single side-band filter for a heterodyne type sub-milimeter wave receiver.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.165-166
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• 2006

By using a ceramic material with dielectric constant 37, the miniature waveguide ceramic bandpass filter was implemented. The proposed waveguide ceramic bandpass filte was based on the mode matching method and simulation process. For overcoming high power, We used the connector at in/output of waveguide ceramic bandpass filte. The result of power test satisfied the 30W. The product will used as a parts of repeater for wibroband.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.143-146
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• 2002

A multilayer two-stage bandpass filter using dissimilar low-temperature cofired-ceramic (LTCC) materials is proposed in this paper. The proposed bandpass filter is composed of ceramic substrates with different dielectric constant instead of single ceramic material from top to bottom layer. Inductive elements are designed in a low permittivity ceramic layer to reduce parasitic effects and loss, while capacitive elements are designed in a high pertimitivity ceramic layer for size reduction. The center frequency of the proposed filter is 1.842 GHz, and the performance of the filter is analyzed and compared with the conventional LTCC filter with single material in terms of integration density, size reduction, and performance improvement.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.139-145
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• 2008

In this paper, a microstrip surface wave antenna(SWA) with a frequency selective surface structure(FSS) is designed and measured. A microstrip SWA has many advantages such as low profile, low weight, easy fabrication, and compatibility with monolithic microwave integrated circuits(MMIC). In addition, it has demonstrated monopole like beam patterns. The microstrip SWA consists of two parts : a center-fed modified microstrip patch to excite surface wave, and a periodic patches to support the propagation of the surface waves. To obtain wide bandwidth, the ring type parasitic element is inserted and the circular patch is selected for the unit element in FSS structure. Experimental results show that the microstrip SWA has monopole like beam patterns at 5.9GHz. Impedance bandwidth and gain is 12% and 5.6dBi.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.5
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• pp.47-54
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• 2019

In this paper, we consider a constant modulus (CM) based blind adaptive receiver design for downlink multi-carrier code-division multiple access (MC-CDMA) systems employing simple space-time block coding (STBC). In the paper, filter weight vectors used for the detection of the transmitted symbols are partitioned into its subvectors and then, special relations among the optimal subvectors minimizing the CM metric are derived. Using the special relations, we present a modified CM metric and propose a new blind adaptive stochastic-gradient CM algorithm (SG-CMA) by minimizing the modified CM metric. The proposed blind adaptive SG-CMA has faster convergence rate than the conventional SG-CMA because the filter weight vectors of the proposed scheme are updated in the region of satisfying the derived special relations. Computer simulation results are given to verify the superiority of the proposed SG-CMA.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.11
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• pp.1-9
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• 2003

The electromagnectic modal analysis method for the multiscreen structure with periodic slot array with including conductor thickness effect is presented. The multiscreen structure is seen to be exactly equivalent to a microwave guide closed by phase-shift walls. From this viewpoint, the entire generalized scattering matrix of the multiscreen structure is calculated by the cascade connection of the scattering matrices obtained by the modal analysis at guide junctions and the transmission matrices of guide region. The present method is verified in comparison with the results calculated by the previous method of moment for single screen structure. As an application example of the present method, the spatial filter having multiscreen structure is designed and the interesting characteristics such as transmission and reflection coefficient versus frequency & angle are investigated.