• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07a
• /
• pp.211-214
• /
• 2004

The advantage of ring-shaped electrodeless fluorescent lamp is the removal of internal electrodes and heating filaments that are a light-limiting factor of conventional fluorescent lamps. Therefore, the life time of ring-shaped electrodeless fluorescent lamps is substantially higher than that of conventional fluorescent lamps and last up to 60,000 hours and is intended as a high efficacy replacement for the incandescent reflector lamp in many applications. In this paper, maxwell 3D finite element analysis program(Ansoft) was used to obtain electromagnetic properties associated with the coil and nearby structures. The electromagnetic emitting properties were presented by 3D simulation software operated at 250[kHz] and some specific conditions

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.5
• /
• pp.607-617
• /
• 2014

This paper proposed the M&S(Modeling & Simulation) method of channel characterization of satellite communication in the operating area of satellite OTM(On-The-Move) terminal. In M&S, received signal profile was acquired by HTZ warfare software which uses 3 dimensional map including building, road information and geographical features, and then was analyzed statistically. And a received signal profile and its statistics from M&S data were compared with those from measured data. The research showed that the simulated received signal profile matched the measured one about 74.8 percent and simulated statistics matched well as roadside trees were excluded.

• Journal of electromagnetic engineering and science
• /
• v.10 no.4
• /
• pp.316-321
• /
• 2010

This paper presents a novel fourth harmonic mixer with new structure. The traditional 3-ports fourth harmonic mixer and the novel fourth harmonic mixer are designed by ADS, HFSS and CST simulator. The mixers have been fabricated and tested. The size of the traditional 3-ports fourth harmonic mixer is $12{\times}15$ mm, and the best conversion loss is 18.7 dB according to the measurement. Since the traditional 3-port mixer size is too large to be ranked, we design a novel fourth harmonic mixer for imaging system. The width of the mixing module in the novel fourth harmonic mixer is only 3.65 mm, and this size is fully capable to meet the mixer unit space which is not greater than 5 mm. The simulation result shows that the mixer has good performance, and the experiment result shows that the best conversion loss of the novel fourth harmonic mixer is 16.3 dB at RF signal of 91.3 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.7
• /
• pp.620-624
• /
• 2016

In this paper we designed a current mode logic frequency divider to transmit a baseband amplitude modulated signal. From simulation result, we studied input and output waveforms according to the variation of input bias voltage. For the purpose of the verification of the study, we designed a current mode logic frequency divider at 1,400 MHz. The designed frequency divider operates between 100 MHz and 3,000 MHz, for -33 dBm input power. The circuit draws $I_{total}=30mA$ from $V_{DD}=3V$ supply, and the simulation result shows that an amplitude modulated signal at 1,400 MHz with the modulation index of 0.5 was successfully downconverted to 700 MHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.24 no.3
• /
• pp.352-355
• /
• 2013

In this paper, a high power tuneable resonator for a wireless power transfer system based on magnetic resonance is proposed. A spiral structure is used for a self-resonant coil and tuneable trimmer capacitors are added at the edges of resonant coils such that the frequency can be easily tuned. 3D simulation tools and equivalent circuit modeling method are used for predicting self-resonant frequency and scattering parameters according to the change of capacitor values. From the measurement of the prototype WPT system, the resonant frequency could be controlled from 3.0 MHz to 4.5 MHz and the transmission efficiency way over 50 % when the distance between transmitting coil and receiving coil was 160 mm.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.55 no.3
• /
• pp.146-154
• /
• 2006

We derived a theory of increasing electromagnetic force which acts on arc column for reducing arcing time between electric contacts. A simulation method of arc velocity is presented by calculating blowout force using 3D FEM and drag force acting on arc column. This paper proposes 3 types arc extinguish chamber of different flux path and presents the specific electromagnetic force and arc velocity of each model by the analysis. The result of analysis and experimental proposes the prediction method of arc time when all conditions are same except external magnetic field.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.22 no.1
• /
• pp.76-80
• /
• 2011

This paper has proposed a 3~5 GHz low-power and wideband LNA(Low Noise Amplifier), which has been implemented in a 0.18-${\mu}m$ CMOS technology. The proposed LNA has basically the noise-cancelling topology to achieve a balun-function, wideband input matching, and relative low noise figure. In addition, it has utilized a 2nd-order LC-band-pass filter(BPF) as its output load to achieve higher power gain and lower noise figure with the lowest dc power consumption among previously reported works. The proposed amplifier consumes only 3.94 mA from a 1.8 V supply voltage. The simulation results show a power gain of more than +17 dB, a noise figure of less than +4 dB, and an input IP3 of -15.5 dBm.

• Investigative Magnetic Resonance Imaging
• /
• v.18 no.2
• /
• pp.107-119
• /
• 2014

Purpose : To efficiently evaluate phased array coil performance using a software tool box with which we can make visual comparison of the sensitivity of every coil element between the real experiment and EM simulation. Materials and Methods: We have developed a $C^{{+}{+}}$- and MATLAB-based software tool called Phased Array Coil Evaluator (PACE). PACE has the following functions: Building 3D models of the coil elements, importing the FDTD simulation results, and visualizing the coil sensitivity of each coil element on the ordinary Cartesian coordinate and the relative coil position coordinate. To build a 3D model of the phased array coil, we used an electromagnetic 3D tracker in a stylus form. After making the 3D model, we imported the 3D model into the FDTD electromagnetic field simulation tool. Results: An accurate comparison between the coil sensitivity simulation and real experiment on the tool box platform has been made through fine matching of the simulation and real experiment with aids of the 3D tracker. In the simulation and experiment, we used a 36-channel helmet-style phased array coil. At the 3D MRI data acquisition using the spoiled gradient echo sequence, we used the uniform cylindrical phantom that had the same geometry as the one in the FDTD simulation. In the tool box, we can conveniently choose the coil element of interest and we can compare the coil sensitivities element-by-element of the phased array coil. Conclusion: We expect the tool box can be greatly used for developing phased array coils of new geometry or for periodic maintenance of phased array coils in a more accurate and consistent manner.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.27 no.3
• /
• pp.269-276
• /
• 2016

This paper presents a 2.65 GHz Doherty power amplifier with internally-matched GaN HEMT. Internal matching circuits were adopted to match its harmonic impedances inside the package. Simultaneously, due to the partially matched fundamental impedance, input and output matching networks become simpler. Bond wires and parasitic elements of transistor package were predicted by EM simulation. For the LTE signal with 6.5 dB PAPR, the implemented Doherty power amplifier shows a power gain of 13.0 dB, a saturated output power of 55.4 dBm, an efficiency of 49.1 %, and ACLR of -26.3 dBc at 2.65 GHz with an operating voltage of 48 V.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.9
• /
• pp.967-973
• /
• 2003

This paper presents a new predistortion method which injects the 2nd low-frequency intermodulation signal of RF signals into the input bias line of the amplifier. New 2nd intermodulation signal extraction circuit is also proposed. We have shown that this method can suppress the 3rd IM apparently and sometimes do the 5th IM, through mathematical analysis, then confirmed it with simulation and verified it on the desk test. When the input signal CDMA IS-95 lFA is applied, measured ACPR improvements are 25 dBc, 22.5 dBc, and 6 dBc at 0.885 MHz, l.25 MHz and 2.25 MHz offset respectively. Also, when applying the CDMA IS-95 3FA, the measured ACPR improvement is 20 dBc at 0.885 MHz offset.