• Laser Solutions
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• v.9 no.1
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• pp.17-23
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• 2006

The technologies of laser micromachining are changed toward more complex-micropatterning, from the micro circle-shaped hole drilling to the micro arbitrary-shaped hole drilling. In this paper, the fundamental experiments by using DPSS 3rd harmonic $Nd:YVO_4\;laser({\lambda}=355nm)$ were carried out in order to obtain the feasibility of flexible micropatterning by various fixed masks. Fixed masks and Galvano scanners were investigatde to make micro patterns. from these experimental results, micropatterns on PEN film were rapidly manufactured in large area.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.212-214
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• 2001

This paper proposes a hi-directional current switch with snubber regeneration using Power MOSFETs and to use a loss-less snubber with switching device to perform soft-switching. It results in not only decreasing switching loss in the device drastically, but also improving input ac current waveform distortion. The computer simulation results show that the input current waveform and show the requirements necessary for the elimination of the 3rd harmonic component. We also show the Procedure to design the parameters of the converter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.8 s.99
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• pp.815-824
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• 2005

In this paper, we proposed a new DGS(Defected Ground Structure) Doherty amplifier for IMT-2000 band. Originally, active load-pull analysis of a Doherty amplifier assumes ideal harmonic termination condition. However, there have been no papers considering this ideal harmonic termination condition. We obtained excellent improvements of efficiency, gain, maximum output power as well as superior size reduction of a Doherly amplifier by satisfying the overlooked assumption of ideal harmonic termination through the adaptation of DGS at the output transmission line of carrier and peaking amplifier that is essential for Doherty operation. The amount of both the 2nd and the 3rd harmonic rejection of the proposed DGS Doherty amplifier over the conventional one are 44.92 dB and over 23.77 dB, respectively. The acquired improvement in Pl dB, gain, drain efficiency, and ACPR to WCDMA 1FA signal were 0.42 dB, 0.33 dB, $6.4\%$ and 5.4 dBc, respectively. Moreover, electrical length of $90{\circ}$ is reduced at each of the DGS carrier amplifier path and DGS peaking amplifier path, therefore the whole amplifier circuit size is considerably reduced.

• Journal of Advanced Navigation Technology
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• v.14 no.1
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• pp.20-26
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• 2010

In this paper, a frequency tripler has been designed with 100mW medium-power using P-HEMT. It is designed to obtain 7.2 GHz frequency at the output that is an integer multiple of 2.4 GHz input frequency by using nonlinear device that produces 3rd harmonic. The frequency tripler is designed by using load-pull simulation. To suppress the 2nd and fundamental, notch filter is used for the frequency tripler. The tripler is designed to obtain about 21dBm output power with 15 dBm input, i.e., 6 dB conversion gain and the suppression of 20 dBc at fundamental, and 30 dBc at the second harmonics.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.68-72
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• 2012

In this paper, highly linear power amplifier using bandpass filter based on metamaterial and Composite Right- / Left-Handed (CRLH) structure is proposed. The proposed bandpass filter consist of the series capacitor, series microstrip line and the parallel inductor, parallel microstrip line. The insertion loss is minimized at operation frequency and the $2^{nd}$ harmonic is suppressed by the bandpass filter using the CRLH structure. And we improved the Adjacent Channel Leakage Ratio (ACLR) using the characteristic of the proposed bandpass filter. At 2.14 GHz, we have obtained the output power of 38.83 dBm, the $2^{nd}$ harmonic of .61.33 dBc, the $3^{rd}$ IMD of .54.67 dBc, and ACLR of .51.33 dBc at 5 MHz offset, -56.50 dBc at 10 MHz offset, respectively.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.2
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• pp.72-75
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• 2012

In this paper, high-efficiency DC-AC converter is implemented for the wireless power transmission. The DC-AC converter is implemented by combining the oscillator and power amplifier. Because the conversion efficiency of wireless power transmitter is strongly affected by the efficiency of power amplifier, the high-efficiency power amplifier is implemented by using the Class-E amplifier structure. Also, because the output power of oscillator connected to the input stage of power amplifier is low, high-gain two-stages power amplifier using the drive amplifier is implemented to realize the high-output power DC-AC converter. The dual band harmonic suppression filter is implemented to suppress 2nd, 3rd harmonics of 13.56 MHz. The output power and conversion efficiency of DC-AC converter are 40 dBm and 80.2 % at the operation frequency of 13.56 MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.12
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• pp.1462-1469
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• 2008

This paper proposes the design method based on the Composite Right/Left-Handed(CRLH) structure to miniaturize and enhance the rejection performance in the stopband of the bandpass filter for a VHF band($169{\sim}211\;MHz$). For realization, we used the 0-th order resonance point of the CRLH and the simple theory of Inverter as coupling. The proposed technique is validated by the performance predictions and experiments, (Insertion loss <2 dB, $S_{11}$< -15 dB, suppression of up to the 3rd harmonic) and it is found out that the suggested method enables the size reduction of around 60 % from the conventional filters such as the parallel edge coupled type.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.315-323
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• 1998

$TiO_2$films of rutile and anatase phase have been prepared on silica glass substrates by the sol-gel method using $Ti(i-OC_3H_7)_4$. The effect of additives on the polymorph of $TiO_2$film has been examined in view of degree of crystallization. Third-order nonlinear optical properties of the both film have been investigated by the third harmonic generation method. The measured 3rd order nonlinear optical susceptibility of rutile and anatase thin films were about $1.4{\times}10^{-12}$ and $9.7{\times}10^{-13}$ esu, respectively.

• 전자공학회논문지 IE
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• v.47 no.3
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• pp.47-52
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• 2010

In this paper, a frequency tripler has been designed with 100mW medium-power using P-HEMT. It is designed to obtain 7.2GHz frequency at the output that is an integer multiple of 2.4GHz input frequency by using nonlinear device that produces 3rd harmonic. The frequency tripler is designed by using load-pull simulation. To suppress the 2nd and fundamental, notch filter is used for the frequency tripler. The tripler is designed to obtain about 21dBm output power with 15dBm input, i.e., 6dB conversion gain and the suppression of 20dBc at fundamental, and 30dBc at the second harmonics.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.4
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• pp.293-299
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• 2004

An active RC 2nd order Butterworth filter suitable for a baseband channel-selection filter of a direct conversion receiver is presented. The linearity of the 2nd order Butterworth filter is analyzed. In order to improve the linearity of the filter, the operational amplifiers should have a high linear gain and low 3rd harmonic, and the filter should be designed to have large feedback factor. This second order Butterworth filter achieves-14dBV in-channel (400kHz, 500kHz) IIP3, +29dBV out-channel (10MHz, 20.2MHz) IIP3 and 15.6 $nV/\sqrt{Hz}$ input-referred noise and dissipates 10.8mW from a 2.7-V supply. The analysis and experimental results are in good agreement