• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.2
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• pp.33-40
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• 1992

The design method of signal delay line system using indirect frequency synthesizer is presented. The variable signal delay line system with 2[nsec] step of delay time at center frequency 60[MHz], bandwidth 500[KHz] and range 5.24-5.81[x10S0-6Tsec] is designed and fabricated. The results were met with good characteristics to be variable delay time of average 2.01[nsec] per step.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.7-10
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• 2002

This paper presents a design of 24㎓ GaAs MESFET voltage controlled oscillator using a dielectric resonator(DR) and a frequency doubler. DR modeling has been done to get the effects of resonator size and the gap from transmission line by HFSS at 12㎓, and frequency doubler is used to get 24㎓ Output.

• Proceedings of the IEEK Conference
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• 1999.11a
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• pp.173-176
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• 1999

Frequency responses of the surface acoustic wave(SAW) filters are simulated by using the impulse modeling. The simulation technique of the SAW filters is to use the Fourier transformation to make a correspondence between the impulse response of the filter and the taps in the delay line. Since the Fourier series must be truncated after a finite number of terms, window functions are often used to weight the coefficients to obtain the desirable side-lobe level and bandwidth. The filter design is operated through the iterative simulation procedures. The design process is capable of yielding filters with optimized frequency response characteristics.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.3
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• pp.46-59
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• 1989

The purpose of test fixture is to mechanically couple energy from a shaker into a test specimen. And then it is necessary to design a fixture of shich the fundamental natural frequency is over than one half times as high as the highest frequency of interest. But the dynamic behavior of vibration test fixture is usually different from, often far different from, what has been calculated. In this paper, the optimal dimensionless frequency parameter, ${lambda}$'s, are calculated from the test results of a various and complex shaped fixtures.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.315-318
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• 2002

In this paper, we have studied about the determination methode of the operating frequency, and the design technique for the self-exited electronic ballast. Because we use the saturation characteristics of the ferrite core, the variation of the B/H curve characteristics for the selected core in the most important factor for the stabilization. Although it is impossible to fix the operation frequency, the self-exited electronic ballast is widely used because of its cost and the simplicity of its structure.

• Journal of the Korean Institute of Navigation
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• v.19 no.2
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• pp.99-106
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• 1995

A wide band design method of an electromagnetic wave absorber with square ferrite cylinders in the second layer, which has very wide band frequency characteristics, is proposed and discussed. A theoretical model using the equivalent material constants method is also evaluated and proposed for its accuracy by comparison with Hashin-Shtrikman formulas. Based on the developed model, wide band electromagnetic wave absorbers with excellent reflective frequency characteristics in the frequency range of 30MHz to 3, 690MHz were designed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1993.10a
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• pp.71-75
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• 1993

The Modeling analysis and design of a high frequency LC-type series and LLCC-type parallel resonant converter oprating in the continous conduction is presented. The state-plane diagram representation of the converter response gives and good insight into the converter operation. A set of characterisric frequency are plotted which design parameters can be obtained.

• Journal of Industrial Technology
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• v.14
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• pp.3-17
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• 1994

This paper develops a design technique for approximating nonseparable frequency characteristics by sums and products of separable transfer functions. Therefore nonseparable frequency characteristics includes the four-quadrant symmetry filters. The desired filter with half plan symmetry is obtained by shifting a low pass characteristic in the frequency domain, and by combining these shifted characteristics. Also the paper develops the technique for designing recursive and nonrecursive two dimensional digital filters by the application of a complex transformation to one dimensional low pass filter.

• Journal of the Korean Institute of Navigation
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• v.18 no.2
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• pp.151-158
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• 1994

A wide band design method of an electromagnetic wave absorber using exponentially tapered ferrite, which has very wide band frequency characteristics, is proposed and discussed. The wide band electroma-gnetic wave absorber can be designed by the proposed equivalent material constants method for the re-gions varying spatially in the shape of ferrite. Futhermore, the wide band ferrite electromagnetic wave absorber with taper, which have not only exce-llent reflectivity frequency characteristics but also the band width of 30MHz to 2150 or 2450MHz under the tolerance limits of -20dB reflectivity, were designed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1996.09a
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• pp.125-134
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• 1996

A design method of double layered electromagnetic wave absorbers with cross-shaped ferrite prominence in the second layer which has broad band frequency characteristics was proposed. The broad band electromagnetic wave absorber can be designed under some approximations by the theoretical model using the equivalent material constants method for the second layer. Based on the developed model broad band electromagnetic wave absorbers with excellent reflectivity frequency characteristics in the frequency range of 30MHz to 3,990MHz were designed.