• Journal of information and communication convergence engineering
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• v.8 no.3
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• pp.263-266
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• 2010

In this paper, a novel defected ground structure (DGS) pattern with enhanced effective capacitance (varactor diode) and a hole in PCB center is presented. The increase in effective capacitance enables the new DGS pattern to achieve a lower resonance than the DGS pattern for the same etched square dimension. The hole in the center also can make resonator frequency lower with better characteristic. According to the tunable characteristic of varactor diode, the resonant frequencies can be tunable. Simulation results show that a lower resonance is achieved with active device, compared to a common DGS pattern.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.3
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• pp.763-770
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• 1996

In this paper, the Single-stage Transmission type Injectiong-Locked Oscillator(STILO) was designed and fabicated for the Active Integrated Phased Array Antenna(AIPAA) system. The STILO, which was designed and fabricated by injection-locked technique and hair-pin resonator, has the same 210MHz frequency tuning range of the Voltage Controlled Oscillator(VCO) used by varactor. The locking bandwidth of STILO with 11.5MHz bandwidth, is much better than that of the Injection-Locked Dielectric Resonator Oscillator(ILDRO), And the STILO has the improved noise characteristics in AM, FM, and PM. This STILO is useful for the AIPAA, the coupled VCO array, an the MMIC structure.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.5
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• pp.318-323
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• 2015

We present a new way to create a thermally stable, highly strained germanium (Ge) optical resonator using a novel Ge-on-dual-insulators substrate. Instead of using a conventional way to undercut the oxide layer of a Ge-on-single-insulator substrate for inducing tensile strain in germanium, we use thin aluminum oxide as a sacrificial layer. By eliminating the air gap underneath the active germanium layer, we achieve an optically insulating, thermally conductive, and highly strained Ge resonator structure that is critical for a practical germanium laser. Using Raman spectroscopy and photoluminescence experiments, we prove that the novel geometry of our Ge resonator structure provides a significant improvement in thermal stability while maintaining good optical confinement.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.123-128
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• 2010

We have investigated the properties of the novel triangular ring resonator with the total internal reflection mirrors and the semiconductor optical amplifier for photonic integrated circuits (PIC). A novel triangular resonators containing active and passive sections are fabricated and characterized with various multimode interference (MMI) lengths. The optimum MMI length and width turn out to be 108 and 9 ${\mu}m$, respectively. A free spectral range of approximately 228 GHz is observed near 1558 nm along with an on-off ratio of 9 dB. The proposed triangular resonator has a good advantage to remove the direct coupling between the two access waveguides of the MMI coupler. Hence, such resonators can be directly integrated with other devices making compact and highly functional PIC possible.

• 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 Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.196-199
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• 2005

Flow traveling over a cavity opening forms a vortex due to unstable shear layer and induces an aerodynamic pressure excitation from the diffusion of the vortex convecting out of the trailing edge of the opening. The interaction between the excitation force and the cavity response sustains resonance in the resonator(cavity) and locked-in vortex shedding at the leading edge of the opening. The aerodynamic excitation force can be described from the diffusion of the vortex over the trailing edge and the level of its diffusivity is related to the strength of vorticity seeded at the loading edge. In this study, the control scheme of the internal pressure oscillation was proposed from regulating the vorticity at the leading edge by use of an oscillating spoiler. It was found that the relative motion between the spoiler and the air mass at the cavity opening influenced vorticity strength and the control was achieved by direct feedback of the cavity pressure fluctuation to the actuator.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.354-359
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• 2020

The high vacuum hermetic sealing technique ensures excellent performance of MEMS resonators. For the high vacuum hermetic sealing, the customization of anodic bonding equipment was conducted for the glass/Si/glass triple-stack anodic bonding process. Figure 1 presents the schematic of the MEMS resonator with triple-stack high-vacuum anodic bonding. The anodic bonding process for vacuum sealing was performed with the chamber pressure lower than 5 × 10^-6 mbar, the piston pressure of 5 kN, and the applied voltage was 1 kV. The process temperature during anodic bonding was 400 ℃. To maintain the vacuum condition of the glass cavity, a getter material, such as a titanium thin film, was deposited. The getter materials was active at the 400 ℃ during the anodic bonding process. To read out the electrical signals from the Si resonator, a vertical feed-through was applied by using through glass via (TGV) which is formed by sandblasting technique of cap glass wafer. The aluminum electrodes was conformally deposited on the via-hole structure of cap glass. The TGV process provides reliable electrical interconnection between Si resonator and aluminum electrodes on the cap glass without leakage or electrical disconnection through the TGV. The fabricated MEMS resonator with proposed vacuum packaging using three-layer anodic bonding process has resonance frequency and quality factor of about 16 kHz and more than 40,000, respectively.

• 전기의세계
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• v.29 no.12
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• pp.798-803
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• 1980

A computer program for noise analysis of the audio circuit is developed. The application of the program to the equalizer, low frequency amplifier of radio circuit and cascaded amplifier show good results. The general noise analysis method for cascade operational amplifier is presented. The noise spectral power density is calculated for a resonator active filter.

• Journal of electromagnetic engineering and science
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• v.12 no.4
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• pp.227-233
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• 2012

This paper describes a novel and compact biosensing platform using an RF active system. The proposed sensing system is based on the oscillation frequency deviation due to the biomolecular binding mechanism on a resonator. The impedance variation of the resonator, which is caused by a specific biomolecular interaction results in a corresponding change in the oscillation frequency of the oscillator so that this change is used for the discrimination of the biomolecular binding, along with concentration variation. Also, a Surface Acoustic Wave (SAW) filter is utilized in order to enhance the biosensing performance of our system. Because the oscillator operates at the skirt frequency range of the SAW filter, a small amount of oscillation frequency deviation is transformed into a large variation in the output amplitude. Next, a power detector is used to detect the amplitude variation and convert it to DC voltage. It was also found that the frequency response of the biosensing system changes linearly with three streptavidin concentrations. Therefore, we expect that the proposed RF biosensing system can be applied to bio/medical applications capable of detecting a nano-sized biomolecular interaction.

• Journal of electromagnetic engineering and science
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• v.18 no.2
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• pp.108-116
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• 2018

In this paper, a method of designing a Vivaldi type phased array antenna (PAA) which operates at S-band (2.8-3.3 GHz) is presented. The presented antenna uses broadside coupled split ring resonators (BC-SRRs) for high isolation, wide field of view, and good active S-parameter characteristics. As an example, we design a $1{\times}8$ array antenna with various BC-SRR structures using theory and EM simulations. The antenna is fabricated and measured to verify the design. With the BC-SRR implemented between the two radiating elements, the isolation is shown to be enhanced by 6 dB, up to 23 dB. The scan angle is shown to be within ${\pm}53^{\circ}$ based on a -10 dB active reflection coefficient. The operation of the scan angle is possible within ${\pm}60^{\circ}$ with a little larger reflection coefficient (-7 dB to -8 dB). The proposed design with BC-SRRs is expected to be useful for PAA applications.