• Journal of Sensor Science and Technology
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• v.28 no.2
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• pp.121-126
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• 2019

The voltage-controlled oscillator is one of the fundamental building blocks that determine the signal quality and power consumption in RF transceivers for wireless sensor networks. Ring oscillators are attractive owing to their small form factor and multi-phase capability despite the relatively poor phase noise performance in comparison with LC oscillators. The phase noise of a ring oscillator can be improved by using a coupled structure that works at a lower frequency. This paper introduces a 2.4 GHz low-noise ring oscillator that consists of two 3-stage coupled ring oscillators. Each sub-oscillator operates at 800 MHz, and the multi-phase signals are combined to generate a 2.4 GHz quadrature output. The voltage-controlled ring oscillator designed in a 65-nm standard CMOS technology has a tuning range of 800 MHz and exhibits the phase noise of -104 dBc/Hz at 1 MHz offset. The power consumption is 13.3 mW from a 1.2 V supply voltage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.119-126
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• 2003

In this paper, a cylindrical cavity resonator oscillator with high Q factor is designed and fabricated to improve the phase noise characteristic. A cavity resonator is coupled to oscillating circuit using aperture hole. Measured results show that the cylindrical cavity resonator oscillator (CRO) for Ku-band has less phase noise than the dielectric resonator oscillator (DRO) with the same oscillating circuit. It has output power of +3.92 dBm at the center frequency 13.4015250 GHz and phase noise of -109 dBc/Hz at 100 kHz offset.

• Journal of Astronomy and Space Sciences
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• v.35 no.2
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• pp.75-81
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• 2018

Solar activity has an important impact not only on the intensity of cosmic rays but also on the environment of Earth. In the present paper, a coupled oscillator model is proposed to explain solar activity. This model can be used to naturally reduce the 89-year Gleissberg cycle. Furthermore, as an application of the coupled oscillator model, we herein attempt to apply the proposed model to El $Ni{\tilde{n}}o$-southern oscillation (ENSO). As a result, the 22-year oscillation of the Pacific Ocean is naturally explained. Finally, we search for a possible explanation for coupled oscillators in actual solar activity.

• Bulletin of the Korean Chemical Society
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• v.24 no.2
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• pp.219-221
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• 2003

Rabi oscillation between bound states of a single potential is well known. However the corresponding formula between the states of two different potentials has not been obtained yet. In this work, we derive Rabi formula between the states of a coupled harmonic oscillator which may be used as a simple model for the electron transfer. The expression is similar to typical Rabi formula for a single potential. This result may be used to describe transitions between coupled diabatic potential curves.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.4
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• pp.359-365
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• 2016

In this paper, a novel coupled C type resonator is proposed for improvement of phase noise characteristics that is weak point of oscillator using planar type microstrip line resonator. Oscillator using proposed coupled C type resonator is designed, it has improved phase noise characteristics. At the fundamental frequency of 9.8GHz, 2.4dBm output power and -82.7 dBc@100kHz phase noise have been measured for oscillator with coupled C type resonator. The phase noise characteristics of oscillator is improved about 9.7dB compared to one using the general ${\lambda}/4$ microstrip resonator. Due to its simple fabrication process and planar type, it is expected that the technique in this paper can be widely used for low phase noise oscillators for both MIC and MMIC applications.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.6
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• pp.539-545
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• 2016

In this paper, a novel coupled C type resonator is proposed for improvement of phase noise characteristics that is weak point of oscillator using planar type microstrip line resonator. Oscillator using proposed shorted coupled C type resonator is designed, it has improved phase noise characteristics. At the fundamental frequency of 9.8GHz, 4.87dBm output power and -84.7 dBc@100kHz phase noise have been measured for oscillator with shorted coupled C type resonator. Next, we designed voltage controlled oscillator using proposed shorted coupled C type resonator with varactor diode. The VCO has 33.8MHz tuning range from 9.7807GHz to 9.8145GHz, and phase noise characteristic is -115~-112.5dBc/Hz@100KHz. Due to its simple fabrication process and planar type, it is expected that the technique in this paper can be widely used for low phase noise oscillators for both MIC and MMIC applications.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.3
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• pp.109-115
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• 2000

Numerical model is proposed to estimate dynamic responses of riser with vortex excitation by inline current. Galerkin's finite decomposition method is implemented for the development of a numerical model and vortex excitation is modeled by coupled wake oscillator proposed by Blevins. The numerical results are inspected through the physical interpretation to give the verification and usefulness of the suggested numerical model.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.141-143
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• 2018

Two 110-GHz oscillators have been developed in 65-nm CMOS technology. To study the effect of layout on the circuit performance, both oscillators had the same LC cross-coupled topology but different layout schemes of the circuit. The oscillator with the conventional cross-coupled design (OSC1), showed an output power of -3.9 dBm at 111 GHz with a phase noise of -75 dBc/Hz at 1-MHz offset. On the other hand, OSC2, with a modified cross-coupled line layout, generated an output power of -2.0 dBm at 117 GHz with a phase noise of -77 dBc/Hz at 1-MHz offset. The result indicates that the optimized layout can improve key oscillator performances such as oscillation frequency and output power.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.705-708
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• 2004

In this paper, we proposed that the secure communication method for build small world. In order to secure communication in the small world, we used Chua's oscillator which well represent the chaos dynamics and composed several stage with Chua's oscillator by using coupled synchronization method. This paper shows a secure communication result in the small world network using coupled synchronization method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.701-704
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• 2004

In this paper, we proposed that the synchronization method for build small world. In order to build a small world, we used Chua's oscillator which well represent the chaos dynamics and composed several stage with Chua's oscillator by using coupled synchronization method. This paper shows a synchronization result in the small world network using coupled synchronization method. Not only time series and phase plane are implemented but also degree of synchronization in the small world network is presented.