• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.05c
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• pp.114-117
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• 2001

$(Ba_{0.6-x}Sr_{0.4}Ca_x)TiO_3$(x=0.10, 0.15, 0.20) ceramics were fabricated by the mixed-oxide method and their structural and dielectric properties were investigated with variation of composition ratio and sintering temperature. As a result of the differential thermal analysis(DTA), exothermic peak was observed at around $1020^{\circ}C$ due to the formation of the polycrystalline perovskite phase. BSCT(50/40/10) specimen sintered at $1500^{\circ}C$ showed the highest average grain size(18.25$[{\mu}m]$). Curie temperature and dielectric constant at room temperature decreased with increasing amount of Ca. BSCT(50/40/10) specimen sintered at $1450^{\circ}C$ showed a good dielectric constant, K, (=4324) and dielectric loss, $tan{\delta}$, (=0.972%) properties at 1[KHz].

• Transactions on Electrical and Electronic Materials
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• v.13 no.6
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• pp.322-325
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• 2012

Crystalline silica was synthesized by annealing amorphous silica at $1,300^{\circ}C$ or $1,400^{\circ}C$ for various times, and the crystallinity was estimated by X-ray diffraction (XRD) analysis. In order to prepare a low dielectric material, epoxy/crystalline silica composites were prepared, and the effect of silica content on the dielectric properties was studied under various functions of frequency and ambient temperature. The dielectric constant decreased with increasing crystalline silica content in the epoxy composites, and it also decreased with increasing frequency. At 120 Hz, the value of 5 wt% silica decreased by 0.25 compared to that of 40 wt% silica, and at 23 kHz, the value of 5 wt% silica decreased by 0.23 compared to that of 40 wt% silica. The value increased with increasing ambient temperature.

• Journal of the Korean Ceramic Society
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• v.36 no.7
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• pp.767-772
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• 1999

The effect of B2O3 addition on the sintering behavior dielectric and ferroelectric properties of Ba0.7Sr0.3TiO3 ceramics were investigated. The sample with 0.5wt% B2O3 was sintered under 115$0^{\circ}C$. The dielectric and ferroelectric properties of BST with 0.5wt% B2O3 was as good as BST without B2O3 sintered at 135$0^{\circ}C$ and its dielectric loss was even better When B2O3 was added over 1.0wt% the overdoped B2O3 remained in the specimens and formed a second phase which degraded the sintering behaivor dielectric properties of BST.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.1
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• pp.53-60
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• 2009

$ZrTiO_4$ dielectric thin films were coated by metal-organic decomposition, and annealed by rapid thermal processing up to $900^{\circ}C$ for their crytallization. Crystallized single-phase $ZrTiO_4$ thin films were fabricated above the annealing temperature of $800^{\circ}C$, but their grains were randomly oriented without specific textured orientation. Best dielectric properties were presented by the sample annealed at $800^{\circ}C$ which had crystalline structure and flat surface. Dielectric constant of the film was maintained at 32 throughout full frequency range up to 6 GHz, and dielectric loss was varied between 0.01 and 0.04.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.169-172
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• 2000

In this paper, we evaluated the mechanical and dielectric properties of LDPE depend on $Co_{60}$${\gamma}$-irradiation doses. The chemical analyses for FT-IR, gel content, the mechanical properties for elongation at break and the dielectric parameters for permittivity, tan$\delta$ were discussed as a function of irradiation doses. Test result presented that elongation at break of irradiated LDPE was inversely proportional to gel content. For dielectric analyses, permittivity showed a salient characteristic for various irradiation doses, it was related to polar groups caused radiation degradation and tan$\delta$ of irradiated LDPE increased with irradiation doses.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.663-666
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• 2004

In this paper, we have investigated the structure and dielectric properties of the $(Ba_{0.6}Sr_{0.4})TiO_3$ (BST) thin films film fabricatedon MgO(100)/Si substrate by an alkoxide-based sol-gel method. Both the structure and morphology of films were analyzed by x-ray diffraction (XRD) and atomic force microscope (AFM). For the MgO(100)/Si substrates, the BST thin films exhibited highly (100) orientation. The highly (100)-oriented BST thin films showed high dielectric constant, tunability, and figure of merit (FOM). The dielectric constants, dielectric loss and tunability of the BST thin films annealed at 700 C deposited on the MgO(100)/Si substrates measured at 10 kHz were 515.9, 0.0082, and 54.3 %, respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.367-370
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• 2007

An EEFL with the sodium free alumino-silicate glass of high K and low $tan{\delta}$, has been investigated. As compared with borosilicate and the soda-lime EEFLs, the luminous efficiency as well as the pinhole stability of new EEFLs improves remarkably without blackening of $NaHg_2$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1227-1232
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• 2011

Using the notch and isolation, we investigated the insertion loss and isolation characterics of the fabricated dielectric duplexers and bandpass filters for CDMA and W-CDMA dualband. Insertion loss(Tx band) and isolation(between Tx and Rx) of duplxer were about -2.1708dB and 45dB at CDMA band, respectively. Also, in the case of W-CDMA, the insertion loss(Tx band) and isolation(between Tx and Rx) showed about -2.6946 and 100dB, respectively. Summering the aboved results, fabricated the dielectric duplexers and bandpass filters will be contributed the increase of atttenuation and the decrease of interference at CDMA and W-CDMA dualband.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1484-1486
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• 1998

Recently, extending the local broadcasting and increasing lots of informations, the low-loss communication cable is required in proportion as frequency. The reason of transportation loss causes to using the high frequencies like hundreds of MHz or decades of GHz. For the low transportation loss, it is required the developing-technology of foaming and the high foamed insulator with the dielectric ratio of the nearest to 1. Therefore, there is the purpose of developing the insulating materials for the low dielectric ratio. Also it is important to measure the attenuation, which is one of the important parameters, as the evaluation of transportation characteristic with frequency in the communication cable. In this paper, the result showed that the dielectric ratio(1.4) of the nearest to 1 and low attenuation with high frequency were very related to the transportation and reflection characteristics such as propagation velocity(82.27%), delay time and voltage standing wave ratio(VSWR).

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.275-278
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• 1990

This study investigated electrical characteristics of solid and liquid epoxy rosins by measuring dielectric breakdown and dielectric loss when epoxy resins were exposed to a mixing cure, i.e., Fusion Blend Method. It was found that mixing epoxy resins were superior to dielectric breakdown and has shorter curing time compare with those of pure liquid epoxy resins.