Microwave dielectric constants of silicon, gallium arsenide, and quartz

1988 ◽  
Vol 63 (11) ◽  
pp. 5439-5443 ◽  
Author(s):  
Karlheinz Seeger
Keyword(s):  
Gallium Arsenide ◽  
Dielectric Constants ◽  
Microwave Dielectric

Lattice Parameters of Bronze-Type 3BaO·2R2O3·9TiO2 (R=Sm and Nd) Solid Solutions for Microwave Dielectric Ceramics

1993 ◽  
Vol 37 ◽  
pp. 79-85 ◽  
Author(s):  
Hitoshi Ohsato ◽  
Toshiyuki Ohhashi ◽  
Kazuhiko Sumiya ◽  
Shinya Suzuki ◽  
Takashi Okuda
Keyword(s):  
Low Temperature ◽  
High Dielectric Constant ◽  
Dielectric Constants ◽  
Dielectric Resonators ◽  
Microwave Dielectric Ceramics ◽  
Low Dielectric ◽  
Satellite Broadcasting ◽  
Microwave Dielectric ◽  
Dielectric Ceramics ◽  
High Dielectric

Microwave dielectric ceramics with high quality have received attention due to the rapid progress in microwave telecommunication and satellite broadcasting. The desirable properties in microwave dielectric resonators are a high dielectric constant (εr), low dielectric loss (tanδ) (i.e. high Q (Q =1/tanδ)), and low temperature coefficient of the resonant frequency(τf). Properties of dielectric ceramics in the TiO2-rich region of the BaO-Nd2O3-TiO2 ternary system (Fig. 1) were reported to have excellent dielectric constants, low dielectric losses and low temperature coefficients of capacitance by Kolar et al. (1978).

EFFECTS OF V2O5 ADDITION ON MICROWAVE DIELECTRIC PROPERTIES OF 16CaO-9Li2O-12Sm2O3-63TiO2 CERAMICS

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1021-1027
Author(s):  
YONGJUN GU ◽  
JINLIANG HUANG ◽  
DAOMING SUN ◽  
QIAN LI ◽  
XIAO WANG ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Mixed Oxides ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Dielectric Constants ◽  
Sintering Aid ◽  
Microwave Dielectric

Effects of V 2 O 5 addition on the microwave dielectric properties of 16 CaO -9 Li 2 O -12 Sm 2 O 3-63 TiO 2 (abbreviated CLST) ceramics prepared by conventional mixed oxides method were investigated as a function of V 2 O 5 content and sintering temperature. All the specimens were sintered between 1100°C and 1250°C. The sintering temperature of the CLST ceramics was lowered by 100°C with V 2 O 5 addition. With the changing content of V 2 O 5, the dielectric constants lie between 88.6 and 108.2, while the Q × f values are between 3275 and 6573 GHz. Especially, the specimens doped by 0.75 wt% V 2 O 5 sintered at 1200°C and 1250°C for 3 h show good microwave dielectric properties with Kr =100.4-108.2, Q × f >4500 GHz , and TCF=7-8 ppm/°C. Obviously, V 2 O 5 could be used as a suitable sintering aid that could improve densification and microwave dielectric properties of the CLST ceramics.

B-O Bond Character and Microwave Dielectric Properties of (1-x)CaTiO3-xCa(Zn1/3Nb2/3)O3 Perovskite Ceramics

2009 ◽  
Vol 421-422 ◽  
pp. 69-72
Author(s):  
Jie Shen ◽  
Wen Chen ◽  
Jing Zhou ◽  
Jie Zhu ◽  
Qiong Lei
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Dielectric Materials ◽  
Solid State Reaction Method ◽  
Dielectric Constants ◽  
Identical Result ◽  
Microwave Dielectric ◽  
Calculation Results ◽  
The Relationship

The relationship between the character of the B-site cation–oxygen bond and the microwave dielectric properties in perovskites dielectric materials was studied in this paper. The atomic net charge of CaTiO3 (CT) and Ca(Zn1/3Nb2/3)O3 (CZN) was calculated respectively. The calculating result implies that the covalency of B-O bonds in CZN is stronger than that in CT. This predicted that the dielectric constant and loss of the ceramics will decrease after CZN incorporated in CT. To confirme the prediction, (1-x)CT-xCZN microwave dielectric ceramics were prepared by solid state reaction method with ZnNb2O6 as precursor. The structure analysis in terms of tolerance factor gives an identical result as calculation. The microwave dielectric properties, such as dielectric constants, Q×f values and τf were studied as a function of composition. With x increasing from 0.2 to 0.8, the dielectric constant linearly decreases from 109 to 49.37, the Q×f value increases from 8,340 to 13,200 GHz, and τf decreases from 321 to -18 ppm/°C. The properties trends are consistent with the previous calculation results, and confirm the relationship between the character of B-O bond and dielectric properties.

Microwave Dielectric Properties of A-Site Modified Pb(Mg1/2W1/2)O3

2007 ◽  
Vol 280-283 ◽  
pp. 1-4
Author(s):  
Jian Jiang Bian ◽  
Hong Bo Gao ◽  
Xiao Wu Wang
Keyword(s):  
Dielectric Properties ◽  
Structural Difference ◽  
Microwave Dielectric Properties ◽  
Dielectric Constants ◽  
Sintering Behavior ◽  
Microwave Dielectric ◽  
Increase With Increase ◽  
A Site ◽  
Perovskite Type ◽  
Perovskite Type Structure

The sintering behavior, microstructure and microwave dielectric properties of A-site modified Pb(Mg1/2W1/2)O3 with Ca2+, Ba2+and La3+ were investigated in this paper. It is discovered that a series of single-phase perovskite type solid solutions with A-site vacancies were formed for Pb1-3/2xLax(Mg1/2W1/2)O3 (0 £ x £ 2/3)). The solid solution took cubic perovskite type structure (Fm3m)with random distribution of A-site vacancies when 0 < x < 0.5, and tetragonal or orthorhombic structure with the ordering of A-site vacancies when 0.5 £ x £ 2/3. However, the solid solubility of Ba(Mg1/2W1/2)O3 and Ca(Mg1/2W1/2)O3 in Pb(Mg1/2W1/2)O3 is limited to 15 and 5 mol%, respectively, in spite of no structural difference between the end member. It was also found that the A-site substitution with Ca2+, Ba2+and La3+ for Pb2+ has no influences on the degree of B-site ordering between Mg2+ and W6+. However, the antiferroelectric Tc decreases with increase in the content of A-site substitution. The dielectric constants and temperature coefficient of resonant frequency of La3+ modified Pb(Mg1/2W1/2)O3 are much lower than that of. Ca2+and Ba2+ modified Pb(Mg1/2W1/2)O3, and decrease with increasing La content. However, its Q×f values is much higher than that of Ca2+and Ba2+ modified Pb(Mg1/2W1/2)O3, and increase with increase in La content. Relatively good combination microwave dielectric properties were obtained for Pb1-3/2xLax(Mg1/2W1/2)O3 with x=0.56: er=28.7, Q×f=18098, and tf=-5.8ppm/oC.

Effects of CuO-V2O5-Bi2O3 Additions on the Microstructure and Microwave Dielectric Properties of 0.42ZnNb2O6-0.58TiO2 Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 27-30
Author(s):  
Jin Wang ◽  
Zhen Xing Yue ◽  
Ying Chun Zhang ◽  
Zhi Lun Gui ◽  
Long Tu Li
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Dielectric Constants ◽  
Microwave Dielectric

The effects of additions on the microstructure and microwave dielectric properties of 0.42ZnNb2O6-0.58TiO2 (ZNT) ceramics were investigated systematically. The sintering temperature of ZNT ceramics doped with different amounts of CuO, Bi2O3 and V2O5 can be effectively reduced. The phase of doped samples was studied compared to the undoped ZNT ceramics. For densified ZNT ceramics with the increasing amount of dopant CuO-Bi2O3-V2O5, the dielectric constants (εr) of densified samples ranges from 38 to 42, the Q×f values decrease evidently and ranges from 13300 GHz to 5000 GHz and the τf values are shifted toward negative.

Sintering Temperature Influence on Microwave Dielectric Properties of TiO2-ZrO2 Ceramics

2010 ◽  
Vol 660-661 ◽  
pp. 646-651
Author(s):  
José Vitor C. Souza ◽  
Pedro José Castro ◽  
Maria do Carmo de Andrade Nono ◽  
Sergio Luiz Mineiro
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Dielectric Constants ◽  
Dielectric Resonators ◽  
Temperature Influence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Dielectric Ceramics

Dielectric ceramics have been widely investigated and used for microwave applications such as resonators and filters. The present study deals with the influence of sintering temperature on microwave dielectric properties of TiO2 ceramics with 10, 20, and 30 wt% ZrO2. Three compositions have been developed through mixing procedures and then tested for each sintering temperature: 1500 and 1400 °C. X-ray diffraction and scanning electron microscopy are carried out aiming to explain the ceramic behavior of each sample. The dielectric constants of different ceramics for both temperatures varied from 85.4 to 62.6, while their quality factor due to dielectric losses varied from 3110 to 1630. The Q decrease is attributed to the non uniform grain growth and to the obtained crystalline phases. The best microwave parameters were obtained for the ceramics sintered at 1400 °C, which can be applied in microwave circuits as dielectric resonators.

Sign in / Sign up

Export Citation Format

Share Document