• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.6
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• pp.509-515
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• 2009

In this paper, we analyzed and evaluated noise suppression characteristic of EM wave absorber. We fabricated several absorber samples in different ratios of Sendust and Amorphous with CPE(Chlorinated Ploy-ethylene) as binder and calculated material constants by measured S-parameter. Then, we confirmed that the noise suppression characteristic of EM wave absorbers using microstrip line. A microstrip line with EM wave absorber placed on its top was used to evaluate the conduction noise suppression. As a result, noise suppression effect show different charateristic by changing relative permeability. Therefore, EM wave absorber using Sendust show excellent characteristic. In particular the maximum power absorption over 90 % in 1.7 GHz to over 6 GHz has obtained when composition of Sendust:CPE=80:20wt.%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.2
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• pp.152-160
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• 2013

In this paper, to the aim of wideband SSN(Simultaneous Switching Noise) suppression characteristic, investigation of spiral resonator are used in conjunction with bead which is commonly used for noise suppression method. Bead works effectively to suppress the power noise up to the first harmonic of fundamental frequency, 0.8 GHz, and spiral resonator suppress noise well in the frequency range of SRF(Self Resonance Frequency) which is inversely proportional to the length of spiral. Thus, when bead used in conjunction with a spiral the noise suppression characteristic is determined by the one of higher impedance element of the two in the frequency range and achieves more broadband filtering characteristic. The case for using 22 nH bead turns out 4.8, 2.0, 0, and, 0.6 dB, and the case for using 22 nH bead in conjunction with 3-turns spiral achieves more wideband characteristic of 9.5, 8.3, 6.1, and 9.9 dB power noise suppression performances at the first, second, third, and fourth harmonics, respectively. The peak-to-peak voltage levels decrease from 76 mV to 56 mV using 22 nH bead, and the level decrease rapidly to 34 mV when using in conjunction with bead and 3-turn spiral. Thus more wideband SSN suppression characteristic can be achieved using bead with spiral.

• Journal of electromagnetic engineering and science
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• v.6 no.3
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• pp.160-164
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• 2006

This paper describes a compact printed helical resonator and its application to a microwave oscillator circuit implemented in coplanar waveguide(CPW) technology. The high Q-factor and spurious-free characteristic of the resonator contribute to the phase noise reduction and the harmonic suppression of the resulting oscillator circuit, respectively. The designed resonator resonating at the frequency of 5.5 GHz showed a loaded Q of 180 in a chip area of only 40 % of the corresponding miniaturized hairpin resonator without any spurious resonances. The fully planar oscillator incorporated with this resonator showed additional phase noise reduction of 10.5 dB at 1 MHz offset and a second harmonic suppression enhancement of 6 dB when compared to those of a conventional CPW oscillator without the planar helical resonator(PHR) structure.

• Journal of information and communication convergence engineering
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• v.15 no.4
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• pp.237-243
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• 2017

This paper presents an analysis of the electromagnetic interference of a heterogeneous power bus where electromagnetic bandgap (EBG) cells are irregularly arranged. To mitigate electrical-noise coupling between high-speed circuits, the EBG structure is placed between parallel plate waveguide (PPW)-based power buses on which the noise source and victim circuits are mounted. We examine a noise suppression characteristic of the heterogeneous power bus in terms of scattering parameters. The characteristics of the dispersion and scattering parameters are compared in the sensitivity analysis of the EBG structure. Electric field distributions at significant frequencies are thoroughly examined using electromagnetic simulation based on a finite element method (FEM). The noise suppression characteristics of the heterogeneous power bus are demonstrated experimentally. The heterogeneous power bus achieves significant reduction of electrical-noise coupling compared to the homogeneous power buses that are adopted in conventional high-speed circuit design. In addition, the measurements show good agreement with the FEM simulation results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.936-939
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• 2006

The pneumatic isolator is widely adopted for anti-vibration of precision measuring and manufacturing equipments. But, when the precision demand on anti-vibration is extreme or the load is moving, the performance of anti-vibration can not meet satisfaction. In these cases, as a complementary, active vibration suppression system can be added for advanced performance. In this paper, an active control system is presented, which uses electromagnetic actuators for vibration suppression. The anti-vibration characteristic of pneumatic isolator is analyzed for system modeling and actuator specifying. The modeling and the 3D dynamic simulation is performed for control system design. For the electromagnetic actuator design, the magnetic flex density and the current-force characteristic analysis are achieved.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.101-106
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• 2005

This paper presents a new microwave oscillator incorporating a corrugated coplanar waveguide (CCPW) electromagnetic bandgap (EBG) structure as its terminating resonance component. The use of a compact CCPW EBG structure was effective in reducing the phase noise and improving the harmonic characteristics of the microwave oscillator circuit without additional backside processing and drastic size increment. The fully planar CCPW oscillator oscillating at the frequency of 5.41 GHz showed a phase noise characteristic of -90.7 dBc/Hz at 100kHz offset and a second harmonic suppression of 42.67 dB.

• ETRI Journal
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• v.28 no.4
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• pp.529-532
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• 2006

This letter describes a compact printed helical resonator and its application to a microwave oscillator circuit implemented in coplanar waveguide (CPW) technology. The high quality (Q)-factor and spurious-free characteristic of the resonator contribute to the phase noise reduction and the harmonic suppression of the resulting oscillator circuit, respectively. The designed resonator showed a loaded Q-factor of 180 in a chip area of only 40% of the corresponding miniaturized hairpin resonator without any spurious resonances. The fully planar oscillator incorporated with this resonator showed an additional phase noise reduction of 10.5 dB at a 1 MHz offset and a second harmonic suppression enhancement of 6 dB when compared to those of a conventional CPW oscillator without the planar helical resonator structure.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.293-297
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• 2009

In this thesis, design of a VCO(Voltage controlled Oscillator) with a novel tuning mechanism is presented for the Radar system. This circuit, the 9.5 GHz oscillator is designed and implemented by restructuring microstrip resonator to raise Q value and to require a wide frequency tuning range. This product is fabricated on 2.6 Teflon substrate and device is NE722S01. In this paper, The new microstrip resonator VCO is proposed to achieve the characteristic of a wide frequency tuning range. This microstrip resonator VCO shows the phase noise characteristic of -108.3 dBc/Hz at 1 MHz offset from the fundamental frequency, the output power of 5.7 dBm and the second harmonic suppression of -38 dBc for the VCO are obtained. The manufacture VCO shows a frequency tuning range of 193.8 MHz. The proposed micro trip resonator VCO can be used for X-band Radar System with required tuning range.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.1 no.1
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• pp.1-9
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• 2002

In this paper, a DRO (Dielectric Resonator Oscillator) with high stability in DSRC(Dedicated Short Range Communication) is designed and fabricated. The DRO shows the phase noise characteristic of -109.3 dBc/Hz at 100 kHz offset from the fundamental frequency. The output power of 11.53 dBm, and the second harmonic suppression of 55.33 dBc for the DRO are obtained. This DRO with high stability of the phase noise characteristic can be used for the system in DSRC.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.11
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• pp.13-22
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• 2010

This paper proposed the dual-loops multiphase DLL based mixed VCO/VCDL for a high frequency phase noise suppression of the input clock and the multiple frequencies generation with a precise duty cycle. In the proposed architecture, the dual-loops DLL uses the dual input differential buffer based nMOS source-coupled pairs at the input stage of the mixed VCO/VCDL. This can easily convert the input and output phase transfer of the conventional DLL with bypass pass filter characteristic to the input and output phase transfer of PLL with low pass filter characteristic for the high frequency input phase noise suppression. Also, the proposed DLL can correct the duty-cycle error of multiple frequencies by using only the duty-cycle correction circuits and the phase tracking loop without additional correction controlled loop. At the simulation result with $0.18{\mu}m$ CMOS technology, the output phase noise of the proposed DLL is improved under -13dB for 1GHz input clock with 800MHz input phase noise. Also, at 1GHz operating frequency with 40%~60% duty-cycle error, the duty-cycle error of the multiple frequencies is corrected under $50{\pm}1%$ at 2GHz the input clock.