• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.5
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• pp.391-399
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• 2017

At present the general trend of modern electronics is toward smaller packages and high performance. As an antenna requires high powers, the EMC(Electromagnetic Compatibility) problems of the transmission line stage is becoming crucial day by day. In this paper, a transmission line excited by the electromagnetic fields from an infinitesimal electric dipole antenna is analyzed using the modified telegrapher's equations. The analytical equations are derived for arbitrarily positioned electric dipole with reference to a transmission line. To verify our approach, the induced voltage and current at the terminal were computed by the proposed approach and compared with those obtained by the electromagnetic simulation solver. Furthermore, the induced currents at the terminal of a transmission line excited by the electric dipoles at various positions were investigated using our approach.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.8
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• pp.933-939
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• 2008

In this paper, a new composite electromagnetic bandgap(EBG) structure using magnetic materials is proposed for simultaneous switching noise(SSN) suppression in the high-speed digital circuits. The proposed EBG structure has periodic unit cells of square-patches connected by spiral-shaped bridges. The magnetic materials are located on the unit cells of spiral-shaped EBG. The real part of the permeability shifts bandgap to the lower frequency region due to the increased effective inductance. The imaginary part of the permeability has magnetic loss that decreases parasitic LC resonance peaks from between the unit cells. As a result, the proposed structure has the lower cut-off frequency compared with conventional EBG structure and -30 dB SSN suppression bandwidth from 175 MHz to 7.7 GHz. The proposed structure is expected to improve the power integrity and reduce the size of the EBG power plane.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.11
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• pp.1164-1171
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• 2014

Bulk Current Injection(BCI) test is a method of injecting current into Integrated Circuit(IC) using a current injection probe to qualify the standards of Electromagnetic Compatibility(EMC). This paper, we propose a microstrip coupler structure that can replace the BCI current injection probe that is used to inject a RF noise in standard IEC 62132-part 3 documented by International Electrotechnical Commission. Conventional high cost BCI probe has mostly been used in testing automotive ICs that use high supply voltage. We propose a compact microstrip coupler which is suitable for immunity testing of low power ICs. We tested its validity to replace the BCI injection probe from 100 MHz to 1,000 MHz. We compared the power[dBm] that is needed to generate the same level of noise between current injection probe and microstrip coupler by sweeping the frequency. Results show that microstrip coupler can inject the same level of noise into ICs for immunity test with less power.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.12
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• pp.1097-1104
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• 2016

The infrared camera is difficult to satisfy the RE-102 specification of Mil-Std-461. Especially, in the case of UAV electronics, shielded cable is not used, so it is difficult to meet the electromagnetic compatibility standard. In the RE-102 test of the IR camera for UAV, radiated noise exceeding 30 dBuV/m was observed in the range of 50 MHz to 200 MHz. As a result of pcb em scan, peak noise which caused by the harmonic frequency of the digital control signal clock was observed. Radiated noise was reduced by up to 22.9 dBuV/m by applying the spread spectrum clock generator(SSCG) with 3 % down spreading method to the camera control clock.

• Journal of electromagnetic engineering and science
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• v.9 no.3
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• pp.130-140
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• 2009

The design theory and experimental results of a true random noise radar system are presented in this paper. Target range information can be extracted precisely by correlation processing between the delayed reference and the signal received from a target, and the velocity information by the Doppler processing with successive correlation data. A K-band noise radar system was designed using random FM noise signal, and the characteristics of the fabricated system were examined with laboratory and outdoor experiments. A C-band random FM noise signal was generated by applying a low-frequency white Gaussian noise source to VCO(Voltage Controlled Oscillator), and a K-band Tx noise signal with 100 MHz bandwidth was obtained by using a following frequency multiplier. Two modified wave-guide horn arrays were designed and fabricated, and used for the Tx and Rx antennas. The required amount of Tx/Rx isolation was attained by using a coupling cancellation circuit as well as keeping them apart with predetermined spacing. A double down-conversion scheme was used in the Rx and reference channels, respectively, for easy post processing such as correlation and Doppler processing. The implemented noise radar performance was examined with a moving bicycle and a very high-speed target with a velocity of 150 m/s. The results extracted by the Matlab simulation using the logging data were found to be in a reasonable agreement with the expected results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1295-1303
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• 2010

In this paper, an effective method has been proposed for selection of white Gaussian noise(WGN) band for radio background noise measurement system under broad band noise environment. MMN which comes from industrial devices and equipment mostly happens in the shape of broad band noise mostly like impulsive noise and this is the main reason for increasing level in the present radio noise measurements. The existing method based on singular value decomposition has weak point that it cannot give good performance for the broad band signal because it uses signal's white property. The proposed method overcomes such a weakness of singular value decomposition based method by using signal's Gaussian property based method in parallel. Moreover, this proposed method hires a modelling based method which uses parameter estimation algorithm like maximum likelihood estimation(MLE) and gives more accurate result than the method using amplitude probability distribution(APD) graph. Experiment results under the natural environment has done to verify feasibility of the proposed method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.2
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• pp.115-122
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• 2016

In this paper, wideband Ku-band downconverter was designed to receiver digital satellite broadcasting. The low-nose downconverter was designed to form four local oscillator frequencies(9.75, 10, 10.75 and 11.3 GHz) representing a low phase noise due to VCO-PLL with respect to input signals of 10.7 to 12.75 GHz and 3-stage low noise amplifier circuit by broadband noise matching, and to select intermediate frequency bands by digital control. The developed low-noise downconverter exhibited the full conversion gain of 64 dB, and the noise figure of low-noise amplifier was 0.7 dB, the P1dB of output signal 15 dBm, and the phase noise -85 dBc@10kHz at the band 1 carrier frequency of 9.75 GHz. The low noise block downconverter(LNB) for wideband digital satellite broadcasting designed in this paper can be used for global satellite broadcasting LNB.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.322-323
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.209-210
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.79-80
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• 2014