• ETRI Journal
• /
• 제35권3호
• /
• pp.538-541
• /
• 2013

A compact microstrip lowpass filter (LPF) with an elliptic function response is proposed. A high equivalent capacitance and inductance between the structures of the resonator result in the sharp transition band of 0.04 GHz from 4 GHz to 4.04 GHz with an attenuation level of -3 dB and -20 dB, respectively. To improve the LPF rejection band, multiple open stubs are connected to the proposed resonator. A filter with a 3-dB cut-off frequency at 4 GHz is designed, fabricated, and measured, and agreement between the measured and simulated results is achieved. The results show that a stopband bandwidth of 131% with a suppression level better than -20 dB is obtained while achieving a compact size with a wide stopband.

• ETRI Journal
• /
• 제32권2호
• /
• pp.195-203
• /
• 2010

A new vertical transition between a substrate integrated waveguide in a low-temperature co-fired ceramic substrate and an air-filled standard waveguide is proposed in this paper. A rectangular cavity resonator with closely spaced metallic vias is designed to connect the substrate integrated waveguide to the standard air-filled waveguide. Physical characteristics of an air-filled WR-22 to WR-22 transition are compared with those of the proposed transition. Simulation and experiment demonstrate that the proposed transition shows a -1.3 dB insertion loss and 6.2 GHz bandwidth with a 10 dB return loss for the back-to-back module. A 40 GHz low-temperature co-fired ceramic module with the proposed vertical transition is also implemented. The implemented module is very compact, measuring 57 mm ${\times}$ 28 mm ${\times}$ 3.3 mm.

• International Journal of Ocean System Engineering
• /
• 제2권3호
• /
• pp.139-150
• /
• 2012

This paper presents an improved guidance algorithm for autonomous underwater vehicles (AUV) in 3D space for generating smoother vehicle turn during the course change at the way-points. The way-point guidance by the line-of-sight (LOS) method has been modified for correcting the reference angles to achieve minimal calculation and smoother transition at the way-points. The algorithm has two phases in which the first phase brings the vehicle to converge to a distance threshold point on the line segment connecting the first two way-points and the next phase generates an angular path with smoother transition at the way-points. Then the desired angles are calculated from the reference and correction angles. The path points are regularly parameterized in the spherical coordinates and mapped to the Cartesian coordinates. The proposed algorithm is found to be simple and can be used for real time implementation. The details of the algorithm and simulation results are presented.

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
• /
• pp.584-584
• /
• 2000

Electronic structures of ordered Fe$_3X (X = Al, Si), and their derivative ternary alloys of Fe_2TX (T = 3d transition metal) have been investigated by using the linearized muffin-tin orbital (LMTO) band method. The role of the coupling between substituted transition metal and its neighbors is investigated by calculating the magnetic moments and local density of states (LDOS). It is shown that it is essential to include the coupling beyond nearest neighbors in obtaining the magnetic moment of Fe alloy. The preferential sites of T impurities in Fe_3X are determined from the total energy calculations. The derivative ternary alloys of Fe_2TX have characteristic electronic structures of semi-metal for Fe_2VAI and (nearly) half-metal for Fe_2TAI (T = Cr, Mn) and Fe_2TSi (T = V, Cr, Mn)

• 한국세라믹학회지
• /
• 제48권5호
• /
• pp.471-478
• /
• 2011

Investigations of crystal structure and phase transition of $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics doped with A-site substitution impurity (La, Nd) or B-site substitution impurity (Sb, Nb) at 2 mol% concentration were carried out. X-ray diffraction patterns of impurities doped $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics have been measured at pressures up to ~5 GPa with diamond anvil cell and synchrotron radiation. The patterns were obtained at room temperature using methanol-ethanol mixture as pressure-transmitting media. In order to refine the crystal structure, Rietveld analysis has been performed. The structures of impurities doped $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics are tetragonal in space group P4mm at ambient pressure and are transformed into a cubic phase in space group Pm$\bar{3}$m as the pressure increases. In this study, when A-site substitution donor $La^{3+}$ or $Nd^{3+}$ ion was added to $Pb(Zr_{0.52}Ti_{0.48})O_3$ ceramics, the phase transition phenomena showed up at the pressure of 2.5~4.6 GPa, but when B-site substitution donor $Nb^{5+}$ or $Sb^{5+}$ ion was added to it, the phase transition appeared at relatively lower pressure of 1.7~2.6 GPa.

• International Journal of Contents
• /
• 제11권1호
• /
• pp.15-20
• /
• 2015

The purpose of this research is to study methods for performing transition that have visual representation of corresponding animations with no bounce in subsequently recognized user information when attempting to interact with a virtual 3D character in real-time using user motion. If the transitions of the animation are needed owing to a variety of external environments, continuous recognition of user information is required to correspond to the motion. The proposed method includes linear interpolation of the transition using cross-fades and blending techniques. The normalized playing time of the source animation was utilized for automatically calculating the transition interpolation length of the target animation and also as the criteria in selecting the crossfades and blending techniques. In particular, in the case of blending, the weighting value based on the degree of similarity between two animations is used as a blending parameter. Accordingly, transitions for visually excellent animation are performed on interactive holographic projection systems.

• 한국전자파학회논문지
• /
• 제29권4호
• /
• pp.266-269
• /
• 2018

본 논문에서는 Q 대역에서 사용가능한 무인항공기 라디오미터 응용 소형 도파관-마이크로스트립 전이구조를 제안하였다. 제안된 전이구조는 간단하면서도 소형이며, 쉽게 정합이 되고, 크기와 제작 오차에 덜 민감한 특징을 가진다. E 평면 패치형태를 가지는 제안된 전이구조는 캐비티 장착뿐 아니라, 도파관-마이크로스트립 기판의 정렬오차에도 덜 민감한 것이 특징이다. 주요파라미터의 최적화에는 3차원 시뮬레이터인 ANSYS사의 HFSS를 사용하였다. Back-to-back 구조에 대하여 중심 주파수에서 20 dB 이상의 반사손실과 1 dB 이하의 삽입손실을 가졌으며, 36 GHz에서 42 GHz까지 반사손실 15 dB 이상의 우수한 성능을 가졌다.

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 2011년도 자성 및 자성재료 국제학술대회
• /
• pp.155-155
• /
• 2011

• 한국자기학회:학술대회 개요집
• /
• 한국자기학회 1998년도 추계연구발표회 논문개요집
• /
• pp.94-94
• /
• 1998

• 한국전자파학회논문지
• /
• 제24권3호
• /
• pp.270-277
• /
• 2013

본 논문에서는 초고주파 대역에서 활용 가능한 ridge 기판 집적 도파관(RSIW:Ridge Substrate Integrated Waveguide)과 기판 집적 도파관(SIW: Substrate Integrated Waveguide) 간의 전이 구조를 제안한다. 제안된 전이 구조는 일정한 간격으로 도통 비아를 삽입하여 임피던스 정합과 전계 정합을 하였으며, 광대역 정합 특성을 갖는다. 측정 결과에서 20 dB 이하의 반사 손실 대역이 9.21~12.41 GHz이고, 중심 주파수 11 GHz 기준으로 비대역폭이 29.1 %임을 확인하였다. 또한, 가용 대역폭에서 급전 선로 부분을 제외한 전이 구조만의 삽입 손실은 최대 0.49 dB이다.