• 전기학회논문지
• /
• 제59권6호
• /
• pp.1083-1086
• /
• 2010

The $Sr_{0.7}Bi_{2.3}Nb_2O_9$ thin films were deposited on Si substrate using RF magnetron sputtering method. And the SBN thin films were annealed at 650~800$[^{\circ}C$]. The surface rougness showed about 0.42[nm] in annealed thin film at $650[^{\circ}C$]. The dielectric constant(150) of SBN thin film was obtained by annealing temperature above $700[^{\circ}C$]. The voltage dependence of dielectric loss showed a value within 0.02 in voltage ranges of -10~＋10[V]. The dielectric constant characteristics showed a stable value with the increase of frequency. Also, the SBN thin films annealed at $750[^{\circ}C$] showed a fatigue-free characteristics up to $1.0\times10^8$ cycles.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
• /
• pp.229-232
• /
• 1997

A free space transmission method using standard gain horn antennas in the frequency range from 9.0 to 10.5GHz is applied to determine the dielectric properties of grain such as rough rice, brown rife and barley. The dielectric constant and loss factor, which depend on the moisture content of the wetted grain are obtained from the measured attenuation and phase shift by vector network analyzer. The effect of density fluctuation, which is an important parameter governing the dielectric properties of grain, on the dielectric constant and loss factor is presented. A new density-independent model in terms of measured attenuation and moisture density is proposed for reducing the effects of density fluctuation on the moisture content measurement.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 하계학술대회 논문집
• /
• pp.660-663
• /
• 2001

The devices of BST thin films to composite (Ba$\_$0.7/ Sr$\_$0.3/)TiO$_3$using sol-gel method were fabricated by changing of the depositing layer number on Pt/Ti/SiO$_2$/Si substrate. The thin film capacitor to be ferroelectric devices was investigated by structural and electrical properties. The thickness of BST thin films at each coating numbers 3, 4 and 5 times was 2500[${\AA}$], 3500[${\AA}$], 3800[${\AA}$]. The dielectric factor of thin film when the coating numbers were 3, 4 and 5 times was 190, 400 and 460 on frequency 1[MHz]. The dielectric loss of BST thin film was linearly increased by increasing of the specimen area.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
• /
• pp.549-552
• /
• 2002

$(SrBi_2Nb_2O_9)_{0.5}-(Bi_3TiNbO_9)_{0.5}$ ceramics were fabricated by the mixed-oxide method, and the structural and electrical properties with variation of ball-milling time were investigated. All SBN-BTN specimens showed the typical polycrystalline X-ray diffraction patterns without the presence of the second phase. The SBN-BTN specimen sintered at $1200^{\circ}C$ and ball-milled for 168h showed the average grain size of $16{\mu}m$. The dielectric constant and dielectric loss of the SBN-BTN specimen sintered at $1150^{\circ}C$ and ball-mill for 72h were 225, 0.4% at 1KHz, respectively.

• 전기의세계
• /
• 제30권10호
• /
• pp.639-644
• /
• 1981

PVC is a kind of electric insulation polymer. But we get some deteriorations in electrical characteristics of the PVC, when it is used on the radioactive field. In order to find out the cause of the deterioration, we investigate the surface-resistance, volume-resistance, dielectric constant and dielectric loss angle of the soft and hard PVC which is irradiated by the Co$^{60}$ .gamma. radioactivity. From the experiment, we can conclude the followings 1. Radio-activity proof characteristic in the soft PVC is stronger than in the hard PVC. 2. The resistance of PVC which is irradiated by the radio-activity decrease exponentially. 3. The dielectric constant and the dielectric loss angle of PVC irradiated by Co$^{60}$ .gamma.ray reach maximum value in first few time.

• 전자공학회논문지A
• /
• 제33A권3호
• /
• pp.38-46
• /
• 1996

The purpose of this study is to develop the miniaturized duplexer filter for mobile communications using high dielectric constant (${\varepsilon}$r > 100, 180) ceramic resonators. Duplexer filter was ocmposed of ceramic resonators which has been developed using BNT system and SCT system, respectively. Developed duplexer filter was formed to have Tx frequency band at 836.5 (($\pm$12.5)MHz and Rx frequency band at 881.5 ($\pm$12.5)MHz. Insertion loss at Tx frequency band was 1.41dB and 1.46dB, insertion loss at Rx frequency band was 3.49dB and 3.65dB, respectively. Especially, duplexer filters using dielectric cermaics with ${\varepsilon}$r = 180 were 8% smaller than commercially manufactured duplexer filters using dielectric ceramics with ${\varepsilon}$r = 90 by murata.

• 한국세라믹학회지
• /
• 제30권8호
• /
• pp.671-677
• /
• 1993

Effects of PbTiO3 addition on dielectric properties and extent of PbO loss in Nd-doped Pb(Mg1/3Nb2/3)O3 system were investigated. As the proportion of dopping increased, the phase transition temperature shifted to low region, and the dielectric constant at room temperature decreased rapidly. But as the proportion of PbTiO3 increased, the phase transition temperature shifted to high retion, and the dielectric constant at room temperature increased. The substitution of Nd3+ for Pb2+ decreased the amount of PbO evaporation, therefore the sample sintered well in case of only 1 mole% adding excess PbO.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.440-443
• /
• 2000

The (Sr$_{1-x}$ Ca$_{x}$) thin films ale deposited OR Pt-Coated electrode(Pt/TiN/SiO$_2$/Si) using RF sputtering method with substitutional contents of Ca. The maximum grain of thin films is obtained at SCT15 thin film. The dielectric constant was increased with increasing the substitutional contents of Ca, while it was decreased if the substitutional contents of Ca exceeded over 15[mol%]. The temperature properties of the dielectric loss have a stable value within 2% independent of the substitutional contents of Ca.Ca.

• Elastomers and Composites
• /
• 제32권5호
• /
• pp.309-317
• /
• 1997

Estimation of the dielectric properties of insulating silicone rubbers added reinforcing fillers $(SiO_2,\;0{\sim}140phr)$ are very important to investigate the polymer structure. The characteristies of the dielectric absorption in insulating silicone rubbers were studied in the frequency range from 30Hz to 1MHz at the temperature range from $0{\sim}170^{\circ}C$. In the case of non-filled specimen, the dielectric loss is due to the syloxane which is the main chain of silicone rubber at the low temperature below $50^{\circ}C$ and the frequency at 330Hz, and is due to methyl and vinyl radical over the frequency of 1MHz. It is confirmed that the methyl radical or the vinyl radical becomes thermal oxidation at the high temperature over $100^{\circ}C$ and then the dielectric disperssing owing to the carboxyl radical Is appeared. In the case of filled specimen, the dielectric constant is in creased with the additives of reinforcing fillers due to the effect of interfacial polarization explained by MWS(Maxwell-Wagner-Sillars)'s law. The dielectric loss is decreased by the disturbance of reinforcing fillers that is permeated between networks.

• 비파괴검사학회지
• /
• 제22권4호
• /
• pp.369-376
• /
• 2002

마이크로파 자유공간전송기법을 이용하여 생물자원인 곡류의 유전특성을 비파괴 방법으로 측정하였다. 마이크로파를 송신하고 수신할 수 있는 혼 안테나, 샘플홀더, network analyzer 를 이용하여 9.5 GHz에서의 마이크로파 측정 시스템을 구성하였다. 여러 가지 수분함량에서 산물밀도가 서로 다른 시료를 투과하여 나오는 마이크로파의 감쇠와 위상 변이로부터 유전상수와 유전손실을 측정하였다. 시료의 유전상수와 유전손실은 샘플홀더 내에 충진되는 시료의 수분함량과 산물밀도가 증가함에 따라 증가하였으며 수분함량과 산물밀도의 팝으로 표시되는 수분밀도를 이용할 경우 산물밀도와 시료 품종의 변이를 보정할 수 있는 것으로 나타났다.