• The Journal of the Acoustical Society of Korea
• /
• v.29 no.7
• /
• pp.439-447
• /
• 2010

In this paper, the resonant characteristic of a Tonpilz transducer with a fixed tail mass has been researched and the feasibility to utilize the transducer in that resonant frequency has been analyzed. The additional resonance is occurred by adhering an elastic tube to the tail mass of a conventional Tonpilz transducer and fixing the other end of the tube. The characteristic of this low resonant mode is analyzed by means of the finite element method, then it is shown that this mode is affected by the variation of the stiffness of the tube as well as the mass of the head mass and tail mass. Based on the analysis results, the Tonpilz transducer is designed to meet specific performance conditions.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.9 no.10
• /
• pp.1175-1180
• /
• 2014

In this paper, the open ring type DGS(Defected Ground Structure) resonator, applicable to MMIC(Monolithic Microwave Integrated Circuit), is proposed to improve phase noise characteristics of RF oscillator. This resonator is planar type, therefore, it easy to design miniaturrized., and takes relatively high Q value. Modeling the equivalent parameter of resonator is needed, when designing the RF oscillator with resonator. The mathematical method to solve the equivalent parameter of the resonator from the measured results of resonator is introduced in this paper. To verify the method, DGS resonator with 5.8 GHz center frequency is fabricated, for measuring characteristics and calculating the equivalent parameter. The result from this process is compared with the data of the ADS simulation, and as a result both were identical.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.2
• /
• pp.273-279
• /
• 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, and oscillator for 5.8GHz band is designed using proposed split ring resonator. 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. Because it is possible that varactor diode or lumped capacitor is placed on the gaps of split ring resonator, resonant frequency can be controlled by bias voltage. We can design voltage controlled oscillator using proposed split ring resonator. Thus, 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.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.5
• /
• pp.1096-1103
• /
• 1990

A finite element method is used for analyzing the resonant characteristics of three- dimensional wind tunnel with circular cross section. The resonant frequencies of wind tunnel is nearly constant in Mach number range of 0.0-0.2. The resonant frequencies and modes of three-dimensional low speed wind tunnel have been calculated. The 20-node isoparametric element gives accurate results compared with the experimental results.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.56-56
• /
• 2003

최근 정보통신 분야의 급격한 발달로 인하여 무선통신에 사용되는 주파수 영역 또한 계속 높아짐에 따라 대역통과 필터 소자의 삽입 손실, 소비 전력, 크기, MMIC화에 대한 많은 연구가 진행되고 있다 압전 현상을 이용한 박막형 공진기가 이러한 요구를 충족시키고, 현재의 SAW filter를 대체할 소자로 떠오르고 있다. 본 실험에서는 단결정 미세 구조를 만들 수 있고, 압전 효과 또한 우수하며, Surface Micromachining보다 비교적 제조 공정이 간단하고 선택적 에칭이 가능한 Bulk Micromachining을 이용하여 Si$_3$N$_4$ Membrane을 이용한 중심주파수 5.2GHz인 두께 진동모드 Film Bulk Acoustic Wave Resonator(FBAR)를 제작하고 공진기의 고주파 특성을 평가하였다. Membrane구조 형성을 위해 Backside면인 Si$_3$N$_4$, Si은 RIE(Reactive Ion Etching)와 선택적 에칭용액인 KOH로 각각 에칭하여 Membrane을 갖는 구조로 중심주파수 5.2GHz인 두께 진동모드 FBAR를 설계 및 제조하였다. 체적 탄성파 공진 현상은 r.f Magnetron Sputtering법으로 증착한 AIN 압전박막과 Mo전극으로부터 발생 가능하였다. 본 연구에서는 0.9$\mu\textrm{m}$-Si$_3$N$_4$ Membrane을 이용해 FBAR를 제작/평가하고, RIE을 통해 Membrane을 제거해 가면서 공진기의 특성 즉, Quality factor와 유효전기기계결합계수(K$_{eff}$) 및 S parameter특성을 비교 측정해 보았다. 측정해본 결과 Membrane Free일때가 훨씬더 공진 특성이 우수함을 볼 수 있다

• The Transactions of the Korean Institute of Power Electronics
• /
• v.14 no.4
• /
• pp.323-332
• /
• 2009

In this paper, operating characteristics of multi-output LLC resonant converter are described and analyzed. Especially, voltage gain characteristics and an equivalent resonant frequency in the multi-output LLC resonant converter are changed by the influences due to the several load conditions and the secondary leakage inductances of multi-output transformer. Based on the theoretical analysis and simulation results considered the characteristics of voltage gain and load variation, prototype of the 540W 3-output LLC resonant converter for 42 inch PDP TV power module is built and the experimental results are described.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
• /
• 2000.11a
• /
• pp.359-363
• /
• 2000

기존의 직사각형 마이크로스트립 평면구조 패치 안테나를 변형하여 패치상에 오목한 구조를 갖는 새로운 3차원 패치구조의 마이크로스트립 안테나를 제안하고, 그 공진주파수와 대역폭 변화 특성을 연구하였다. 오목형 구조의 크기에 따라 공진 주파수와 대역폭이 증가하는 것으로 관찰되었으며, 복사특성은 기존의 마이크로스트립 안테나와 거의 유사한 특성을 나타내었다. 새로운 3차원 구조를 갖는 패치에 대한 해석 및 설계는 FDTD 방법을 사용하였으며, 이에 대한 검증을 위해 기존의 마이크로스트립 안테나와 제안된 오목형 구조의 안테나를 제작하여 측정한 결과 공진주파수 및 대역폭 특성 변화가 해석결과와 잘 일치함을 확인할 수 있었다.

• Proceedings of the International Microelectronics And Packaging Society Conference
• /
• 2001.11a
• /
• pp.41-47
• /
• 2001

폴리머 박막은 반도체 패키징, MEMS 구조물은 물론 MCM-D 등의 기술에도 널리 쓰이고 있다. 또한 대부분 폴리머/금속의 다층구조의 형태를 띠고 있어 이 상태의 기계적 특성의 이해는 더욱 중요하다. 본 연구에서는 폴리머 박막의 기계적 특성을 측정하기 위한 새로운 방법이 제안된다. 제안된 방법은 최근 발달된 마이크로머시닝기술을 사용하여 구현된 공진형 스트링구조를 이용하게된다. 폴리머 기계적 특성치와 스트링의 공진특성은 서로 상관 관계를 갖게되며 이러한 공진특성의 측정은 기계적 특성의 실시간 관찰을 가능하게 해준다. 본 논문에서는 공진형 스트링을 이용하여 폴리이미드의 잔류음력과 폴리이미드/금속간의 접착 내구성을 정량화하는 방법을 제안한다. 제안된 측정방법은 단순히 스트링구조 뿐만 아니라 다른 기계적 구조에도 응용이 가능하다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.10
• /
• pp.2639-2645
• /
• 2009

This paper describes a CPW oscillator using a spiral resonator. Spiral resonators are very useful in design CPW oscillators since they show a relatively higher Q than CPW hairpin and helical resonators. Prior to the design of oscillators, three CPW resonators are designed and compared. Electromagnetic (EM) simulation are performed for an improved design in design the CPW resonators and oscillators. Three oscillators are designed at 5.7 GHz using the mentioned CPW resonators. The measured output power of three CPW oscillators using the helical, hairpin, and spiral resonators are 2.55 dBm, 2.64 dBm, and 4.98 dBm, respectively. In addition, the size of three resonators are $102.15mm^2,\;130.05mm^2,\;80.625mm^2$, respectively, so it is proven that the proposed CPW oscillator using the spiral resonator has a smaller size than the others.

• Journal of Sensor Science and Technology
• /
• v.8 no.5
• /
• pp.407-413
• /
• 1999

The resonant frequency of dielectric rod resonator can be calculated very accurately by means of the concept of electric and magnetic walls from the symmetry. But in a real situation, when the supporter is placed in the cavity, asymmetry appears due to the supporter and its dielectric constant. Then we need research into the resonance characteristic of asymmetric dielectric resonator. In this paper, for the dielectric rod resonator which is placed in the asymmetric position in the conducting cavity, the equation for resonance characteristic was derived and the resonant frequency was calculated with the eigenfunction expansion method. We found that the calculated resonant frequency is very accurate when it was compared with the experimental result and that asymmetry affects the resonant frequency more in TM mode than in TE or in hybrid mode.