• Journal of the Semiconductor & Display Technology
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• v.16 no.2
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• pp.85-88
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• 2017

In this paper, we have designed and fabricated a RF-DC voltage multiplier for 5.8GHz microwave wireless power transmission. In order to obtain higher voltage, the RF-DC voltage multiplier with 10 diodes (D-10) and the receiver module with an antenna and BPF (Band Pass Filter) was manufactured. The measured and compared results show that the voltages of the proposed one are lower than those of the previous tripler module up to 40cm. However, the voltage of the proposed one with the voltage multiplier is higher than that of the tripler module at the distances of 45cm and 50cm due to the voltage multiplier with 10 diodes.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.55-58
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• 2002

This paper describes an RF module for 2.4GHz wireless audio/video transmission. The pre-processed baseband input signals are FM-modulated using a VCO and then transmitted through an antenna after RF filtering. The designed circuits are implemented using a Teflon board of which the size is 52mm${\times}$62mm. The measured maximum output signal levels are around -3dBm and the harmonics are less than -450dBc. The manufactured module consumes 130mA from a 8V supply.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.1
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• pp.70-77
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• 2014

In this work, we studied basic characteristics of transmission lines employing various PSS (periodic strip structure) on silicon substrate for application to a miniaturization of RF components. According to the results, the transmission lines employing various PSS showed wavelength shorter than conventional coplanar waveguide due to their strong wave characteristics. Especially, with-contact structure was most effective for a miniaturization of RF component. Concretely, the size of the transmission line employing with-contact was only 4.39 % of the conventional coplanar waveguide, According to the bandwidth extraction result, the bandwidth of the transmission lines employing various PSS structures were wider than 384 GHz. Above results indicate that the transmission lines employing various PSS can be effectively used for application to a broadband and miniature RF component, and especially, with-contact is most effective for a miniaturization of RF components.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.1-8
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• 2011

In this paper, data transmission corrugated horn antenna for RF sensor satellite system and its radiation characteristic are presented. The proposed antenna is designed, fabricated and measured to obtain the maximum gain at ${\pm}60^{\circ}$ of its radiation patterns. The result of the proposed antenna is that the return loss is less than -15 dB and the gain is over 5 dBi at ${\pm}60^{\circ}$ of its radiation patterns. From these results, it is confirmed that the proposed can be used as data transmission corrugated horn antenna for RF sensor satellite system.

• Proceedings of the KIEE Conference
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• 2003.11b
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• pp.27-30
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• 2003

Wireless power transmission system is one of the very interesting field not only in a technical and economical point of view but also that people are still trying to realize lossless power transmission. This paper has a purpose on the efficient power transmission at the passive type ICcard by using wireless power transmission system. The most difficult but important part of the passive type RF-ID system is building the system that supplies power from Reader-antenna to IDcard-antenna. To check what is the most efficient way to deliver power depending on what kind of specifications of the power-amp in reader, antenna and antenna in IDcard is for operating IDcard circuit efficiently receiving the power from reader-antenna. For this, we used 125kHz sinewave for RF signal as a basic specification, power-amp : OP-Amp for amplifying signal and AB Class push-pull power-amp for amplifying power, loop type antenna.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.777-783
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• 2009

In this paper, we implemented a wireless power transmission system at 2.45 GHz. The transmission power is limited within 20 dBm according to the ISM frequency regulations. We used two zero-bias Schottky diode and optimized the RF-DC converter for working a clock at 80 cm distance using a receiver with a single antenna and an Rf-DC converter to reduce parts and cost compared to previously reported literatures.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.112-122
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• 2024

Recently, as unmanned aerial vehicle technology such as drones has developed, there are many environmental, social and economic benefits, but if there is malicious intent against important national facilities such as airports, public institutions, power plants, and the military, it can seriously affect national safety and people's lives. It can cause damage. To respond to these drone threats, attempts are being made to introduce detection equipment such as RF scanners. In particular, power transmission towers installed in substations, power plants, and Korea's power system can affect detection performance if the transmission tower is located in the RF scanner detection path. In the experiment, a commercial drone was used to measure the signal intensity emitted from the drone and confirm the attenuation rate. The average and maximum attenuation rates showed similar trends in the 2.4 GHz and 5.8 GHz bands, and were also affected by the density of the structure.

• Journal of the Semiconductor & Display Technology
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• v.20 no.2
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• pp.29-33
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• 2021

A 5.8-GHz 1W wireless power transmission system was used for charging a smart phone. The voltage of one RF power receiver with antenna was not enough for charging. Several power receivers for charging a smart phone was connected serially. The voltage of several RF power receivers are highly enough for charging a smart phone within 50cm. However, the lack of current from small capacitances of RF-DC converters is not suitable for charging smart phone. It means very long charging time. In this paper, the voltage multiplier circuits for RF-DC converters were analyzed to increase the current and voltage at the same time to reduce the charging time in smartphone RF wireless charging. Through the analysis of multiplier circuits, the 7-stage parallel multiplier circuit with voltage-doubler units are suitable for charging the smartphone, which supplies 5V and 700mA at 3V@5.8GHz.

• Proceedings of the KIEE Conference
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• 2007.04a
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• pp.61-63
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• 2007

In high field (> 3 T) MR imaging, the magnetic field inhomogeneity in the target object increases due to the nonuniform electro-magnetic characteristics and relatively high Larmor frequency. Especially in the body imaging, the effect causes more serious problems resulting in locally high SAR(Specific Absorption Ratio). In this paper, we propose an optimized parallel-transmission RF coil element structure and show the utility of the coil by FDTD simulations to overcome the unwanted effects. Three types of TX coil elements are tested to maximize the efficiency and their driving patterns(amplitude and phase) optimized to have adequate field homogeneity, proper SAR level, and sufficient field strength. For the proposed coil element of 25 cm ${\times}$ 8 cm loop structure with 12 channels for a 3.0 T body coil, the 73% field non-uniformity without optimization was reduced to about 26% after optimization of driving patterns. The experimental as well as simulation results show the utility of the proposed parallel driving scheme is clinically useful for (ultra) high field MRI.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1666-1668
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• 2004

By wireless transmission data, there is high possibility to get distortion and lose by noise and barrier on wireless. If the data check damaged and lost at receiver, can't make it clear and can't judge whether this data is right or not. Therefore, by wireless transmission data need the data error check algorithm in order to decrease the data's distortion and lose and to monitoring the transmission data as real time. This study consists of RF station for wireless transmission, Water Level Meter station for water level measurement and Error check algorithm for error check of transmission data. This study is also that investigation and search for error check algorithm in order to wireless digital data transmission in condition of the least data's damage and lose. Designed transmitter and receiver with one - chip micro process to protect to swell the volume of circuit. Had designed RF transmitter - receiver station simply by means of ATMEL one - chip micro process in the systems. Used 10mW of the best RF power and 448MHz-449MHz on frequency band which can get permission to use by Frequency Law made by Korean government