• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.11
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• pp.74-81
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• 2007

In this paper, CMOS analog-to-digital converter (ADC) with a 6-bit 1GSPS at 1.8V is described. The architecture of the proposed ADC is based on a folding type ADC using resistive interpolation technique for low power consumption. To reduce the power consumption, a folder reduction technique to decrease the number of folding blocks (NFB) by half of the conventional ones is proposed. further, a novel layout technique is introduced for compact area. With the clock speed of 1GSPS, the ADC achieves an effective resolution bandwidth (ERBW) of 500MHz, while consuming only 60mW of power. The measured INL and DNL were within $\pm$0.5 LSB, $\pm$0.7 LSB, respectively. The measured SNR was 34.1dB, when the Fin=100MHz at Fs=300MHz. The active chip occupies an area of 0.27$mm^2$ in 0.18um CMOS technology.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3201-3206
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• 2012

In this paper, the simplified design methodology for rotation of polarization plane using a square waveguide is proposed. In order to optimize the characteristics of $180^{\circ}$ polarizer operating from 14.3GHz to 14.8GHz in Ku-band, the modified mode matching method and piecewise power tower interpolation are applied to the polarizer design. The optimized results show that the frequency bandwidth in VSWR<2 has covered 500MHz in the Ku-band and phase difference between two orthogonal modes $TE_{10}$and $TE_{01}$ is $180^{\circ}{\pm}1^{\circ}$ in the range of 14.3GHz~14.8GHz. The cross polarization loss has obtained below 40dB and the insertion loss has 0.1dB in the passband. Therefore, the proposed polarizer is suitable for practical Ku-band system requiring the low VSWR and compact size.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.4
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• pp.550-563
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• 1999

A wavelet-Galerkin scheme based on the time-dependent Maxwell's equations is presented. Daubechies wavelet with two vanishing wavelet moments is expanded for basis function in spatial domain and Yee's leap-frog approach is applied. The shifted interpolation property of Daubechies wavelet family leads to the simplified formulations for inhomogeneous media without the additional matrices for the integral or material operator. The stability condition is formulated. The dispersion characteristics are analyzed and compared with those of finite difference time domain and multiresolution time domain methods. The analyses show the excellent trade-off between the regularity and the support width of the basis function. Although the basis function has only two vanishing wavelet moments, it is enough to provide negligible dispersive error in the numerical analysis and its compact support enables only several involved terms per nodes. The storage effectiveness, execution time reduction and accuracy of this scheme are demonstrated by calculating the resonant frequencies of the homogeneous and inhomogeneous cavities.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.3
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• pp.646-655
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• 1990

A practically useful system for elastic-plastic fracture mechanics analysis has been developed. The developed system is comprised of the deformation plasticity failure assessment diagram(DPFAD) approach and the J-integral/Tearing modulus(J/T) approach. The system contains analysis routines for five types of fracture specimens : compact tension, center cracked tension, single edge craked plate in uniform tension, single edge cracked plate in three point bending and double edge cracked plate in tension. A double interpolation scheme was adopted to interpolate J values from the EPRI developed EPFM handbook and the Newton-Raphson method was used to obtain proper loadings for displacement control conditions. A graphic output system was utilized to present numerical results. Several case studies were performed to evaluate the accuracy and the usefulness of the code. It was found that the J/T approach and the DPFAD approach yielded similar results. However, the DPFAD approach is more convenient for qick assessment of integrity of cracked structures while the J/T approach is more useful in evaluating the full history of the fracture process.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.10
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• pp.7-13
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• 2010

A compact phase interpolator (PI) based spread spectrum clock generator (SSCG) for electromagnetic interference (EMI) reduction is presented. The proposed SSCG utilizes a digitally controlled phase interpolation technique to achieve triangular frequency modulation with less design complexity and small power and area overhead. The novel SSCG can generate the system clock with a programmable center-spread spectrum range of up to +/- 2 % at 200 MHz, while maintaining the clock duty cycle ratio without distortions. The PI-based SSCG has been designed and evaluated in 0.18-um 1.8-V CMOS technology, which consumes about 5.0 mW at 200MHz and occupies a chip size of $0.092mm^2$ including a DLL.