• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.2
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• pp.159-163
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• 2005

This paper gives characterization of ZnO thin film deposited by RF magnetron sputtering method, which is concerned in deposition process and device fabrication process, to fabricate solidly mounted resonator(SMR)-type film bulk acoustic resonator(FBAR). A piezoelectric layer of 1.1${\mu}{\textrm}{m}$ thick ZnO thin films were grown on thermally oxidized SiO$_2$(3000 $\AA$)/Si substrate layers by RF magnetron sputtering at the room temperature. The highly c-axis oriented ZnO thin film was obtained at the conditions of 265 W of RF power, 10 mtorr of working pressure, and 50/50 of Ar/O$_2$ gas ratio. The piezoelectric-active area was 50 ${\mu}{\textrm}{m}$${\times}$50${\mu}{\textrm}{m}$, and the thickness of ZnO film and Al-3 % Cu electrode were 1.4 ${\mu}{\textrm}{m}$ and 180${\mu}{\textrm}{m}$, respectively. Its series and parallel frequencies appeared at 2.128 and 2.151 GHz, respectively, and the qualify factor of the resonator was as high as 401.8$\pm$8.5.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.424-428
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• 2000

In this paper, a MIC(Microwave Integrated Circuit) bandpass filter for wireless LAN(local area network) band is designed using hairpin resonators. The coupling between the hairpin resonators in the filter can be implemented with Y-Tpye coupling or X-Tpye coupling instead of conventional coupling in order to reduce the filter size. The filter with miniaturized hairpin resonator using parallel coupling is smaller in size by 50% more than that of a general hairpin filter

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.90-95
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• 2021

In this paper, the design method for a high-sensitivity compact resonator for chipless RFID tags is proposed. Proposed high-sensitivity compact resonator uses an interdigital-capacitor structure instead of a capacitor-shaped strip structure in a conventional ELC resonator. The length of the electrode plate of the IDC structure is longer than that of the conventional capacitor-shaped structure, resulting in a larger equivalent capacitance of the resonator. This can lower the resonant peak frequency of the RCS characteristic. Two resonators with the same length of the square loop and the width of the strip are fabricated on an RF-301 substrate with a thickness of 0.8 mm. The experiment results show that the resonant peak frequency and value of the bistatic RCS for the ELC resonator were 4.305 GHz and -30.39 dBsm, whereas those of the proposed IDC resonator were 3.295 GHz and -36.91 dBsm. Therefore, the size of the resonator is reduced by 23.5% based on the measured resonant peak frequency of the RCS characteristic.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.10
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• pp.1131-1137
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• 2014

In this paper, oscillator with compact hairpin resonator is used to design the local oscillator of X-band radar system. The proposed hairpin resonator is minimized by increasing capacitance of line end of conventional one. By this method, size can be minimized about 40% compared with the conventional resonator and also can improve phase noise characteristic. The result of oscillator using proposed hairpin resonator is measured in oscillating frequency of 9.05 GHz, output power of 2.47 dBm, and phase noise of -101.4 dBc/Hz. The fabricated oscillator in this paper can minimize design and it's planar structure makes it easy to design MMIC.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.132-135
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• 2002

A RF amplitude equalizer is designed to improve in-band flatness of Rf filters and/or systems using two dielectric resonators and a 90$^{\circ}$ hybrid. The equalizer has good return loss characteristics and V shaped S$_{21}$ response in passband which is suitable to compensate the ripple degradation due to insufficient quality factors of used resonators or narrow band width of filters or systems. After being connected to the equalizer, a 5-pole BPF at 1957MHz, which has 10 MHz bandwidth and 6㏈ ripple, shows only 1.8㏈ in-band ripple and good in- and out- band matched responses within used hybrid bandwidth without additional matching networks.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1538-1543
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• 2013

In this paper, a novel split ring resonator is proposed for improvement of phase noise characteristics that is weak point of oscillator using planar type microstrip line resonator. Oscillator using proposed split ring resonator is designed, it has improved phase noise characteristics. At the fundamental frequency of 5.8GHz, 7.22dBm output power and -83.5 dBc@100kHz phase noise have been measured for oscillator with split ring resonator. The phase noise characteristics of oscillator is improved about 9.7dB compared to one using the general ${\lambda}/4$ microstrip resonator. Next, we designed voltage controlled oscillator using proposed split ring resonator with varactor diode. The VCO has 125MHz tuning range from 5.833GHz to 5.845GHz, and phase noise characteristic is -118~-115.5 dBc/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.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.11
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• pp.1215-1220
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• 2014

In this paper, a local oscillator for X-band radar system is designed and fabricated with GaAs MESFET. GaAs MESFET is good for microwave oscillators because of very low noise figure and high electron mobility. Oscillator design methods in this paper are used the characteristic of negative resistance of active component and impedance matching technique without RF resonator. So, oscillator is designed in compact size because space of RF resonator is reduced and can be applied MMIC technique. Designed oscillator has characteristic of the output power of 2.30 dBm and center frequency of 10.545GHz.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.7
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• pp.308-314
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• 2005

The 2 GHz film bulk acoustic wave resonator(FBAR), one of the most necessary device of the next generation mobile communication system, consisted of solidly mounted resonator(SMR) structure using Brags reflector, was researched in this paper The FBAR applied SiO$_{2}$ and W had large difference of the acoustic impedance to reflector Al to electrode and ZnO to piezoelectric layer. Specially, the FBAR applied the two-step deposition method to improve the c-axis orientation and increase reproducibility of the fabrication device had good performance. The electrical properties of plasma such as impedance, resistance, reactance, $V_{pp},\;I{pp}$, VSWR and phase difference of voltage and current, was analyzed and measured by RF sensor with the variable experiment process factors such as gas ratio, RF power and base vacuum level about concerning the thickness, c-axis orientation, adhesion and roughness. The FBAR device about the optimum condition resulted reflection loss(S$_{11}$) of -17 dB, resonance frequency of 1.93 GHz, electric-mechanical coefficient(k$_{eff}$) of 2.38 $\%$ and Qualify factor of 580. It was seen better qualify than the common dielectric filter at present and expected on business to the filter device of 2 GHz bandwidth with the MMIC technology.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.5
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• pp.412-418
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• 2002

In this paper, the authors present the simulation results and the experimental considerations on the effects of the effects of the VCO oscillation characteristics caused by varying the length of the MSL and the composition capacitance of LC resonation circuity. Simulation was accomplished by nonlinear RF circuit simulator for designing and analyzing the RF characteristis of VCO. The samples with 3 different MSL lengths of which the length is 140mil, 280mil and 560mil respectively were fabricated by screen printing process. The oscillation frequency of each sample(VCO) was tuned to UHF band (750MHz~900MHz) by varying the capacitance of LC resonator circuit. The experimental results showed that the values of phase noise were -82, -93, -97[dBc/Hz] at 50[kHz] offset frequency, the pushing figures were 114, 94, 318[kHz] at applied voltage of $3\pm0.15$[V] and the harmonics were -21, -16, -13[dBc] for MSL lengths of 140mil 280mil, 560mil respectively. The frequency and output variation width were 779~898[MHz], -36~-33[dBm] for MSL with 140mil length; 818~836[MHz], -27.19~27.06[dBm] for 280mil; 751.54~751.198[MHz], -33.44~-33.31[dBm] for 560mil.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.15-15
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• 2003

목적： RF Birdcage Resonator는 그것의 높은 자장 균질성과 신호 대 잡음비의 특성이 좋음으로 인해 MRI와 MRS 연구에 보편적으로 사용되고 있다. 본 연구는 인체를 비롯한 동물실험을 위한 다양한 실험대상에 따라 코일의 크기를 예측하여 Birdcage Resonator를 개발하였다. unloaded와 loaded 상태에서의 전기적인 성향을 Lumped Element Circuit Theory를 따라 일반적인 분석을 하였을 뿐 아니라 실제적인 실험을 통한 분석도 하였다.