• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.195-200
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• 2018

A W-band frequency octupler is implemented on 100-nm GaAs pHEMT process. The fabricated octupler can be used as a local oscillator or a signal source of W-band transceivers. Three common-source doublers are connected in cascade to multiply an input signal of 10.75 GHz to 83 GHz. A common-source amplifier is followed for each doubler to improve the conversion gain and suppress the unwanted harmonics. The fabricated octupler showes high output of more than 6 dBm in the 80 - 84 GHz band and achieved excellent spurious suppression performance over 20 dBc.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.4 s.346
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• pp.67-74
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• 2006

We present the design of a radiometer in W-band which operates simultaneously with a single antenna configured FMCW radar. We choose a total power radiometer(TPR) which shares an antenna and a front-end with the radar for miniaturizing the system. We separate the radiometer signal from the radar signal using a diplexer in IF band. Because the radiometer has an unwanted transmitter section due to the common use of the MMW front-end with the radar, some additional noise signals caused by the transmitter degrade the sensitivity of the radiometer system. To compensate the degradation of sensitivity, we use matching circuits and a diode detector configured as the voltage doubler. Through some experiments, we have verified that the designed radiometer system has good performances in detecting metal targets tying at several hundred meters.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.484-488
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• 2001

The grid voltage of commercial utility power source hi Japan and USA is 100rms, but in China and European countries, it is 200rms. In recent years, In Japan 200Vrms out putted single phase three wire system begins to be used for high power applications. In 100Vrms utility AC power applications and systems, an active voltage clamped quasi-resonant Inverter circuit topology using IGBTs has been effectively used so far for the consumer microwave oven. In this paper, presented is a half bridge type voltage-clamped high-frequency Inverter type AC-DC converter using which is designed for consumer magnetron drive used as the consumer microwave oven in 200V utility AC power system. This zero voltage soft switching Inverter can use the same power rated switching semiconductor devices and three-winding high frequency transformer as those of the active voltage clamped quasi-resonant Inverter using the IGBTs that has already been used for 100V utility AC power source. The operating performances of the voltage source single ended push pull type Inverter are evaluated and discussed for consumer microwave oven. The harmonic line current components In the utility AC power side of the AC-DC power converter operating at ZVS­PWM strategy reduced and improved on the basis of sine wave like pulse frequency modulation and sine wave like pulse width modulation for the utility AC voltage source.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.137-145
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• 2008

In this paper, novel CMOS charge pump having NMOS and PMOS transfer switches and a bulk-pumping circuit has been proposed. The NMOS and PMOS transfer switches allow the charge pump to improve the current-driving capability at the output. The bulk-pumping circuit effectively solves the bulk forward problem of the charge pump. To verify the effectiveness, the proposed charge pump was designed using a 80-nm CMOS process. The comparison results indicate that the proposed charge pump enhances the current-driving capability by more than 47% with pumping speed improved by 9%, as compared to conventional charge pumps having either NMOS or PMOS transfer switch. They also indicate that the charge pump reduces the worst-case forward bias of p-type bulk by more than 24%, effectively solving the forward current problem.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.862-867
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• 2009

This paper presents a study on a rectenna for rectification of incident low power microwave signals with power densities less than 2 mW/$cm^2$ at 2.45 GHz. The proposed rectenna is designed and implemented by a rectifier with voltage doubler structure and a printed Yagi antenna which suppress re-radiation of the second order harmonic of fundamental frequency. The printed Yagi antenna has a gain of about 5 dB, and the measured conversion efficiencies of the rectenna are from 32 % to 42 % when its incident power levels are from 0 dBm to 14 dBm. The developed rectenna is expected to be useful in the power transmission system.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.30-36
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• 2009

Various types of ultra-wideband components with 10's of GHz bandwidth have been developed utilizing a uniplanar ultra-wideband balun, which is a simple microstrip-to-coplanar stripline (CPS) transition structure with the operating frequency range from near DC to over 40 GHz. Developed ultra-wideband components include antennas, mixers, doublers, and detectors in a carrier type and in a surface mountable type. One of surface mountable components, for example, single balanced doubler has output frequency 8 ~ 28 GHz. These high-Performance, low-cost ultra-wideband components may replace expensive conventional components, and also can be used to develop new multi-GHz OWE application areas.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.5
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• pp.50-57
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• 2008

In this paper, a high-efficiency charge pump for use in CMOS image sensor(CIS) is proposed. The proposed charge pump pursues high pumping efficiency by minimizing the switching and reversion losses by taking advantage of operation characteristics of CIS. That is, the proposed charge pump minimizes the switching loss by dynamically controlling the size of clock driver, pumping capacitor, and charge transfer switch based on the operation phase of CIS pixel sensor. The charge pump also minimizes the reversion loss by guaranteeing a sufficient non-overlapping period of local clocks using a tri-state local clock driver adapting the schmitt trigger. Comparison results using a 0.13-um CMOS process technology indicate that the proposed charge pump achieves up to 49.1% reduction on power consumption under no loading current condition as compared to conventional charge pump. They also indicate that the charge pump provides 19.0% reduction on power consumption under the maximum loading current condition.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.4
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• pp.315-322
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• 2009

In the conventional boost converter, the actual duty cycle is limited as the output voltage increases due to increased voltage and current stress of the switch and diode and voltage surge caused by diode reverse recovery. In this paper a new non-isolated boost converter suitable for high gain applications is proposed. The proposed converter has voltage gain of around 6 when the duty cycle is 0.5. Since ZVS is achieved under CCM, the proposed converter has wide ZVS range. Also, voltage ratings of switch and diode are the same as one third of output voltage, and ratings of input and output passive components are reduced due to the interleaving. In addition voltage surge caused by diode reverse recovery is negligible due to ZCS turn-off of diodes. Operating principle of the proposed converter is described and validated through theoretical analysis, simulation and experiment.

• Journal of Power Electronics
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• v.16 no.3
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• pp.1209-1217
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• 2016

This paper presents a novel charge pump scheme that combines the advantages of Fibonacci and Dickson charge pumps to obtain 30 V voltage for display driver integrated circuit application. This design only requires four external capacitors, which is suitable for a small-package application, such as smart card displays. High-amplitude (<6.6 V) clocks are produced to enhance the gate drive of a Dickson charge pump and improve the system's current drivability by using a voltage-doubler charge pump with a pulse skip regulator. This regulation engages many middle-voltage devices, and approximately 30% of chip size is saved. Further optimization of flying capacitors tends to decrease the total chip size by 2.1%. A precise and simple model for a one-stage Fibonacci charge pump with current load is also proposed for further efficiency optimization. In a practical design, its voltage error is within 0.12% for 1 mA of current load, and it maintains a 2.83% error even for 10 mA of current load. This charge pump is fabricated through a 0.11 μm 1.5 V/6 V/32 V process, and two regulators, namely, a pulse skip one and a linear one, are operated to maintain the output of the charge pump at 30 V. The performances of the two regulators in terms of ripple, efficiency, line regulation, and load regulation are investigated.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1038-1044
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• 2011

In this paper, the multichannel intermediate frequency transceiver for broadband multimedia system is designed and the experimental results are analyzed. Basic elements of the transceiver such as frequency synthesizer, amplifier, mixer, automatic gain control amplifier are introduced. The analysis technique described here applies not only to amplifier but also to any other nonlinear components such as mixers and frequency doubler. Through the investigation of the power spectrum density of the transmitted signal, the phase noise of the local oscillator is evaluated below 70 dBc/kHz. The frequency characteristics of the modulated signal is flat within the system bandwidth. Also the effects of adjacent channel interference and supurious emission are analyzed. And the function of automatic gain control amplifier is well operated.