• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.234-238
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• 1992

A sealed-off waveguide $CO_2$ laser with a length of 50 cm and a cross-sectional area of $6\times 6\ttextrm{mm}^{2}$ has been designed and constructed. The laser is transversely excited by RF (13.56 MHz) discharge. Output characteristics of the laser has been investigated performing variations of total gas pressure, input rf power, and mixing ratios of gases. The maximum output power of 9.5 W was obtained under the condition of total gas pressure of 50 Torr, input rf power of 180 W, and gas mixture of 6 : 1 : 2 : 1 of $He:CO_{2}:N_{2}:Xe$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2111-2118
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• 2008

This parer propose a U-dormitory management system based on 13.56MHz RFID system. The proposed U-dormitory management system consists of three parts, the RFID hardware system, the middleware, and the application. RFID hardware system uses 13.56MHz frequency which is suitable for a close range. The middleware is implemented to accept the RFID hardware system values using RS-232c communication method and forward the values to the application. The application is designed to make the DB using the forwarded Haloes, and works based on the DB. The efficacy of the Proposed U-dormitory management system is verified by means of experiments. In the experiments, we set up the system to the dormitory of Daeduk College to show the improvement results of proposed system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.11
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• pp.44-49
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• 2008

We have proposed a clock recovery circuit for 13.56MHz RFID Tags using 100%, ASK RF input signal. The proposed clock recovery circuit generates clock pulses without reference clock by adapting register controlled DLL. The proposed circuit have designed by using a TSMC 0.18um 1P6M CMOS technology. The simulated results show that the phase locking time of the proposed circuit is about 6.4 usec and power consumption is about 43uW at supply voltage of 3.3V.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.484-490
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• 2018

This paper describes an algorithm for calculating load impedance by measuring voltage and current components using a VI sensor in a 13.56 MHz impedance automatic matching system. We propose an algorithm that improves the error rate by using an arbitrary complex calibration load instead of the conventional $50{\Omega}$ calibration load. The error rate is targeted to attain average values of $R_{IN}$ and $X_{IN}$ at 1% and 20% or less, respectively. First, the IF frequency is calculated using a mixer to reduce the error rate. Second, when the arbitrary complex load is used as the calibration load, the error rate $R_{IN}$ decreased from 4.7 % to 0.3 % on average, and $X_{IN}$ decreased from 102 % to 18.3 % on average.

• 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.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.10
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• pp.59-65
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• 2008

We have proposed a UHF/HF multi-band RFID reader, and have implemented it into a system in a package(SiP). The proposed SiP RFID reader has been designed to support both for EPCgloabal Class1 Generation2 protocol of UHF band, and 13.56MHz RFID protocols of ISO14443 A/B type, and ISO15693 standards. The operating mode is controlled by embedded RISC core, and the mode can be selected by users. The area of implemented SiP is $40mm{\times}40mm$ with 4 metal layers. The implemented reader SiP operates at single supply voltage of 3.3V. The maximum current consumption is 210mA. The operating distances are 5cm for 13.56MHz modes, and 20cm for UHF mode.

• Journal of information and communication convergence engineering
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• v.9 no.3
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• pp.260-265
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• 2011

In RFID System, when multiple tags respond simultaneously, a collision can occur. A method that solves this collision is referred to anti-collision algorithm. In 13.56MHz RFID system, STAC protocol is defined as an anti-collision algorithm for multiple tag reading. In STAC protocol, there is no differentiation between the collided tags and others in the identification process. Therefore, tags may never be successfully identified because its responses may always collide with others. This situation may cause the tag starvation problem. This paper proposes a fair identification scheme for STAC protocol. In the proposed scheme, if the number of collided slots is large during a query round, the reader broadcasts a CollisionRound command to begin a collision round. During the collision round, the reader identifies only tags that are experienced collision during the previous query round.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05e
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• pp.92-95
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• 2003

In this paper, the emission properties of electrodeless fluorescent lamp were discussed using the inductively coupled plasma. To transmit the electromagnetic energy into the chamber, a RF power of 13.56MHz was applied to the antenna and considering the Ar gas pressure and the RF electric power change, the emission spectrum, Ar-I line, luminance were investigated. At this time the input parameter for ICP RF plasma, Ar gas pressure and RF power were applied in the range of 10~60m Torr, 10~300W respectively.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.4
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• pp.67-73
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• 2011

We developed a RFID system to effective management and monitoring for school assert. In this paper, RFID system implemented a two way which are control to 13.56MHz for in/outbound order and 2.45GHz for positioning tracking and monitoring. We also make up the contents and database utilizing the labview tool in pc. In addition, the developed system can obtain simultaneously the information from several RFID reader at real time so that it is possible to track the position system, the path moving and the status of asserts in the school. Especially, 2.45GHz system has a function to prevent a assert theft. It is observed from the various and practical experiment that the proposed system is useful for assert management and monitoring.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1695-1697
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• 2003

In this paper the emission properties of electrodeless fluorescent lamp were discussed using the inductively coupled plasma. To transmit the electromagnetic energy into the chamber a RF power of 13.56MHz was appied to the antenna and considering the Ar gas pressure and the RF electric power change, the emission spectrum, Ar-I line, luminance were investigated. At this time the input parameter for ICP RF plasma, Ar gas pressure and RF power were applied in the range of 10${\sim}$60m Torr, 10${\sim}$300W respectively.