In this study, the electrostatic capacity and dielectric loss tangent for 20 μm thick thermal conductivity silicone rubber which is heated at 80 degrees for 8 hours has been measured at temperature of 30℃∼170℃, frequency of 0.1∼1 MHz. The results of degradation evaluation by this study are as follows. In low frequency, it found that the electrostatic capacity decreased with increasing temperature. On the other hand, it confirmed that the range of the electrostatic capacity narrowed with increasing frequency. It confirmed that there are the carboxylic acid structure and C-O bonding at range of wave number 1,000cm-1 to 1,300cm-1.

In this study, the properties of C-V degradation for thermal conductivity silicone rubber sample which is attached by copper-copper, copper-aluminum, aluminum-aluminum on upper-side and under-side has been measured at temperature of 80℃∼140℃. The results of this study are as follows. In case the frequency is increased, it found that the electrostatic capacity increased with increasing temperature to 80℃, 110℃, 140℃ regardless of kind of electrode. It found that the electrostatic capacity increased with becoming high temperature range of frequency regardless of kind of electrode. This result is considered to be caused by thermal absorption on the thermal conductivity silicone rubber sample. It found that the electrostatic capacity decreased with increasing temperature and frequency. This result is considered to be caused by molecular motion of C-F radical or OH radical.

The Sr0.7Bi2.3Nb2O9(SBN) thin films are deposited on Pt electrode(Pt/Ti/SiO2/Si) using RF sputtering method at various deposition temperature. The deposition temperature of optimum was 300℃. SBN thin films were annealed at 500∼700℃ using furnace and RTA, respectively. The surface roughness showed about 2.42 nm in annealing temperature(600℃) of furnace. The capacitance density of SBN thin films were increased with the increase of annealing temperature. The maximum capacitance density of 0.7 ㎌/㎠was obtained by annealing temperature(700℃). The frequency dependence of dielectric loss showed about 0.03 in frequency ranges of 1∼1,000 kHz.

In this study, the frequency properties of electrostatic capacity and dielectric loss for the samples with different types of filler has been measured in through the applied frequency range of 7 kHz -3,000 kHz at temperature of 80℃, 110℃, 140℃, 170℃. The results of this study are as follows. When the sample is degradated at the temperature of 80℃, 110℃, 140℃, 170℃ and the frequency range of 7 kHz -3,000 kHz is applied, It found that the electrostatic capacity of the sample with Polyimide film is larger than the sample with Grass fiber. It found that the dielectric loss for the sample with Polyimide film is larger than the sample with Grass fiber with increasing frequency and temperature in the 80℃, 110℃, 140℃, 170℃ range. Also, the dielectric loss decreased with increasing frequency. In case of the sample with Polyimide film, It found that the electrostatic capacity decreased with increasing temperature, and the dielectric loss gradually decreased with increasing frequency.

In this study, the temperature characteristics of electrostatic capacity and dielectric loss for thesample of Teflon film which is degradated at the 120℃∼200℃ temperature range in the oven for 10 hourshas been measured in through the applied frequency range of 0.1 kHz∼4,800 kHz at temperature of 50℃,90℃, 130℃, 170℃. Also, in the same conditions, the frequency characteristics of electrostatic capacity anddielectric loss for the sample of Teflon film has been measured in through the applied temperature rangeof 30℃∼70℃ on setting frequency of 0.1 kHz, 1 kHz, 10 kHz, 100 kHz. The results of this study are asfollows. When the frequency range of 0.1 kHz∼4,800 kHz applied to the sample of Teflon film, theelectrostatic capacity has been measured at the temperature of 50℃, 90℃, 130℃, 170℃. Through thismeasurement, it found that the electrostatic capacity decreased with increasing temperature. Regarding thisresult, may be it is because the electromagnetic coupling is degraded by thermal degradation. When thesample of Teflon film heated at 280℃ for 10 hours in oven, the dielectric loss has changed from unstablestatus to stabilizing status with increasing the degradation temperature in the 120℃, 160℃, 200℃ range. Inthis measurement, the two spectrums of dielectric loss appeared. It considers that this spectrum ofdielectric loss appeared in 300 Hz is caused by the molecular motion of the C-F or OH group. Throughthis study, It found that the electrostatic capacity decreased with increasing frequency and temperature,and there is no change in dielectric loss, although the frequency increases.

The Sr based ceramic thin films were deposited on Si substrate by RF magnetron sputtering method. And Sr based thin films were annealed at 500～700℃ using RTA. The surface roughness showed about 2.4 nm in annealed thin film at 600℃. The capacitance density of Sr based thin films were increased with the increase of annealing temperature. The maximum capacitance density of 0.6 ㎌/㎠ was obtained by annealing temperature at 700℃. The voltage dependence of dielectric loss showed about 0.02 in voltage ranges of -10～＋10 V. The leakage current density of annealing temperature of 600℃ was the 4.0×10-6 A/㎠ at applied voltage of -5～＋5 V.

In this study, the capacitance and dielectric loss tangent of the silicone rubber which is combined with filler (30 phr∼50 phr) have been measured on the range of 100 Hz∼100 kHz and 30∼170℃. It was found that when the frequency is 0.1 kHz∼100 kHz and the silicone rubber is combined with 30 phr to 50 phr of filler, the capacitance of silicone rubber has increased by about 28.6 pF to 33 pF in 30 phr of filler, about 20 pF to 46.1 pF in 40 phr of filler and about 36.4 pF to 44 pF in 50 phr of filler. It seems that the volume of dielectric loss has gradually increased due to the temperature rise and the rotating of dipole in electric field through the electric dipole generated by the Si-O group which is induced by adding of filler, or the carbonyl group which is caused by oxidation. It seems that the dielectric dispersion in 0.1 kHz is caused by molecular motion of Siloxane group in main chain, and the dielectric dispersion in 10 kHz is caused by molecular motion of Methyl group in side chain.

In this study, the moisture content, charge?discharge current, electrostatic capacity and dielectric loss tangent are measured for the specimen of bisphenol type epoxy resin which is mixed with squared amorphous silica filler and dipped in hot water of 50℃ for 169 days. The results of this study are listed below. The longer of deposition day, the charge and discharge current was increased. It is considered that the reason is because there was water attack through the squared silica surface. The longer of deposition day, the absorption rate of all specimens was increased. It found that the absorption rate reached saturated state after 100 days. The higher frequency and the longer of deposition day, the tanδ was decreased. Also, It found that the tanδ and electrostatic capacity of the specimen which is mixed with squared filler are greater.

PTFE composites for use of microwave substrate were fabricated by impregnation and heat treatment fabrication with glass fabric. This study shows dielectric properties such as dielectric constant and loss can be controlled by thickness of PTFE composite with of pressure condition in heating press process. The dielectric constant of the PTFE composites has decreasing tendency as given higher pressure condition. The dielectric loss has similar result too. Especially, the case of the dielectric loss was affected by the condition of pressure at heating press and had the best performance under 3 MPa. In order to see the reason why thickness conditions make different, their microstructures were also observed.

The Sr0.7Bi2.3Nb2O9(SBNO) thin films were deposited on Si substrate by RF magnetron sputtering method at 300℃ of substrate temperature. And the SBNO thin films were annealed at 650～800℃ using RTA (rapid thermal annealing). The grain of SBNO thin films were increased with the increase of annealing temperature. The dielectric constant (100) of SBNO thin film was obtained by RTA above 750℃. The voltage dependence of dielectric loss showed a value within 0.03 in voltage ranges of -5～＋5 V. Also, the dielectric constant characteristics showed a stable value with the increase of frequency.