• Current Optics and Photonics
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• v.2 no.1
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• pp.96-100
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• 2018

A tunable low-phase-noise microwave generation structure that utilizes an optoelectronic oscillator (OEO) and a fiber Bragg grating (FBG) is proposed and experimentally demonstrated in this article. This structure has no particular requirement for the band width of the laser, and its tunability is realized through adjusting the central frequency of the tunable FBG. A detailed theoretical analysis is established and confirmed via an experiment. A high-purity microwave signal with a frequency tunable from 6 to 12 GHz is generated. The single-sideband phase noise of the generated signal at 10.2 GHz is -117.2 dBc/Hz, at a frequency offset of 10 kHz.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1700-1705
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• 2013

A second harmonic millimeter wave oscillator utilizing sub-harmonic injection-synchronization is presented. A 8.7GHz oscillator with MES-FET is designed, and is driven as a harmonic output oscillator at 17.4GHz by means of sub-harmonic injection-synchronization. The oscillator operates as a multiplier as well as a oscillator in this scheme. Adopting this method, a high sable, high frequency millimeter wave source is obtainable even though self-oscillating frequency of an oscillator is relatively low. The range of injection-synchronization is about 26MHz, and is proportional to the input sub-harmonic power. The spectrum analysis of the 2nd harmonic output frequency shows remarkably decreased the phase noise level.

• Journal of Navigation and Port Research
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• v.28 no.4
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• pp.293-297
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• 2004

In this papers, an S-band oscillator of the low phase noise property using a miniaturized micro-strip hairpin shaped ring resonator is presented The substrate has a dielectric constant $\epsilon_\gamma$＝3.5, a thickness h＝0.508 mm, and loss tangent $tan\delta$＝0.002. A designed and fabricated oscillator shows low phase noise performance of 99. 71 dBc/Hz at 100 KHz offset frequency and of output power 19.584 dBm at center frequency 2.450 GHz. This circuit was fabricated with hybrid technique, but can be fully compatible with the MMIC due to its entirely planar structure.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.861-866
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• 2014

This study evaluates the modeling accuracy of the existing three phase shift models on which the time domain oscillator phase noise theories are based. For the evaluation, this study investigates how accurately the three models can model the phase shift impulse train response of a simple planar oscillator. Evaluation result reveals that Kaertner model most accurately reflects the oscillator's phase shift impulse train responses for five different impulse train inputs, whereas PP model exhibited the worst performance in modeling the phase shift impulse train responses.

• Journal of IKEEE
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• v.17 no.4
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• pp.559-563
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• 2013

This paper analytically proves the equivalence between two main oscillator phase noise theories, which are based on the ISF, and Floquet vector, respectively. For this purpose, this study obtains the power spectral density matrix from the ISF-based phase noise theory. As a result, one can prove that the power spectral density matrix obtained from the ISF-based phase noise theory is essentially equivalent to the power spectral density matrix presented by the Floquet vector-based phase noise theory, which manifests the equivalence of the two main theories. This study is intended to provide deeper insight into the relations between the two main theories.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.462-469
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• 2001

In this paper, local oscillator in K band using low frequency noise upconversion gain anaylsis was designed and measured. We extended Two Signal Method(TSM) to estimate upconversion gain and resulting phase noise. To confirm the validity of the proposed method, a free-running oscillator which had low upconversion gain was designed. The measured oscillation frequency was 23.42 GHz and phase noise at 1 MHz of offset was -105.2 dBc/Hz. Also, this oscillator was operated for subharmonic injection locked osci1lator(SILO). In this case, SILO showed ideal frequency multiplier phase noise characteristics at low subharmonic injection power level.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.1
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• pp.68-74
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• 2008

The substrate integrated waveguide (SIW) structure can be approximated as the rectangular waveguide using common dielectric substrate with via-holes. To realize reflection-type resonator, $50-{\omega}$ microstrip line can be used for coupling with the center plane of the cavity. The oscillator is designed to operate at 9.45 GHz using the reflection-type SIW cavity resonator. The phase noise of oscillator shows -98.1dBc/Hz at 100 KHz offset. In experiment, the reflection type SIW cavity resonator improves the loaded quality factor making the low phase noise oscillator possible. Due to the entirely planar structure of this resonator, this technique can also be adequate in oscillator applications for a low cost and low phase noise performance.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.501-503
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• 2008

This paper presents the design of a 2.4 GHz low phase noise fully integrated LC Voltage-Controlled-Oscillator (VCO) in $0.18{\mu}m$ CMOS technology. The VCO is without any tail bias current sources for a low phase noise and, in which differential varactors are adopted for the symmetry of the circuit. At the same time, the use of differential varactors pairs reduces the tuning range, i.e., the frequency range versus VTUNE, so that the phase noise becomes lower. The simulation results show the achieved phase noise of -138.5 dBc/Hz at 3 MHz offset, while the VCO core draws 3.9mA of current from a 1.8V supply. The tuning range is from 2.28GHz to 2.55 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.11
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• pp.842-850
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• 2018

In this paper, the design and fabrication of a frequency-locked-loop(FLL) 5-GHz oscillator with a single resonator is presented. The proposed oscillator is the simplified version of the previous FLL oscillator with two separate resonators in the VCO and frequency detector. The resonator is commonly used in the VCO and frequency detector of the proposed oscillator configuration. The 5-GHz oscillator is implemented on the hetero-multilayer substrate composed of a Rogers' RO4350B laminate, which has excellent high-frequency performance, and the commercial FR4 three-layer substrate. The frequency locking occurs at approximately 5 GHz and has an output power of 3.8 dBm. The phase noise has a free-run VCO phase noise at frequencies above 1 kHz, and an FLL background noise at frequencies below 1 kHz. For this loop-filter, the phase noise showed an improvement of approximately 12 dB at the offset-frequency of 100 Hz.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.4
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• pp.243-248
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• 2015

Since phase noise is one of the most important parameters in the design of microwave oscillators, several methods have been proposed to reduce the phase noise. These methods have focused on improving the quality factor of resonators, which result in low phase noise oscillators. Dielectric resonators have been widely used for low phase noise in microwave oscillators due to their high quality factor. However this cannot be used in MMIC oscillators because they have a 3D structure. In this paper, to overcome this problem a novel resonator using open ring type DGS is proposed for improvement of phase noise characteristics that is weak point of oscillator using planar type microstrip line resonator, and oscillator for 5.8GHz band is designed using proposed DGS resonator. The open ring type DGS resonator is composed of DGS cell etched on ground plane under $50{\Omega}$ microstrip line. At the fundamental frequency of 5.8GHz, 6.1dBm output power and -82.7 dBc@100kHz phase noise have been measured for oscillator with ring type DGS resonator. The phase noise characteristics of oscillator is improved about 96.5dB compared to one using the general ${\lambda}/4$ microstrip resonator.