249results about How to "Excellent microwave dielectric properties" patented technology

The invention discloses a microwave dielectric ceramic and a preparation method thereof. The microwave dielectric ceramic is mainly composed of ZrO2, TiO2 and Nb2O5; the microwave dielectric property of the microwave dielectric ceramic can be improved by selectively adding MgO, CoO, ZnO, NiO and MnO2; the chemical constitution formula of the ceramic is xZrO3-YTiO2-zA(1+W)/3Nb(2-w)/2O3; in formula (I), A is one or more elements of Mg, Co, Zn, Ni and Mn; x, y and z are molar ratios, wherein x is between 0.2 and 0.7, y is between 0.2 and 0.6,, z is between 0.1 and 0.2, and, x plus y plus z is equal to 1; numerical range of w is l between 0 and 0.5. According to the microwave dielectric ceramic and the preparation method thereof, the ceramic has the characteristics that the dielectric constant is high, the loss is low, and the temperature coefficient is close to zero, and is liable to sinter; the preparation method has the characteristics that the price of raw materials is low, and a technology during production is simple.

The invention discloses a low-temperature sintered microwave medium ceramic material and a preparation method thereof. The material comprises the raw materials with the mol ratio: BaCO3:ZnO:TiO2:Q=1:x:(4+y):z, wherein x=0.01-0.5, y=0.01-0.5, z=0.01-0.1, and Q is glass combustion-supporting agent or BaCu (B2O5); the glass combustion-supporting agent comprises the raw materials with the mol ratio being Li2O:ZnO:B2O3=1:2:7 or Li2O: B2O3-1:2:7=3:2:5. The material can be obtained through traditional solid phase reaction synthesis. The material has lower sintering temperature (is capable of being fired at the temperature below 900 DEG C to form ceramics), is capable of being fired at the temperature of 900 DEG C to form ceramics and has better microwave dielectric property, wherein Epsilon r is equal to 25-35, Q*F is larger than 12,000, and Pi f is equal to -10ppm/DEG C to +30ppm/DEG C; in addition, the material has stable process and good repeatability and can be better co-fired and matched with a silver electrode. The low-temperature sintered microwave medium ceramic material can be used for manufacturing microwave devices, such as lower temperature co-fired ceramic (LLCC) systems, multilayer medium resonators, microwave antennae, wave filters, and the like.

The invention discloses a low-temperature sintered ZnO-MgO-TiO2 system microwave ceramic material and a preparation method thereof. The formula of raw materials of the ceramic material comprises the following compositions: 30 to 45 percent of zinc oxide, 2 to 14 percent of magnesium oxide, 50 to 60 percent of titania and an auxiliary sintering agent. The preparation method comprises: taking the zinc oxide, basic magnesium carbonate and the titania as raw materials, mixing the raw materials, adding a grinding aid for ball milling, drying, sieving and presintering, and obtaining clinker; and mixing the obtained clinker with the titania, the auxiliary sintering agent and an additive, performing drying, granulation and press forming after secondary ball milling, finally sintering the mixture for 2 to 8 hours at a temperature of between 900 DEG C and 1,000 DEG C, and obtaining the ceramic material. The ceramic material prepared by the method has the advantages of superior microwave dielectric property, low sintering temperature, low cost and the like, and is suitable for microwave devices such as multi-layer ceramic capacitors, filters, resonators and dielectric antennas.

The invention provides a low-dielectric constant high-quality factor LTCC microwave medium material and a preparation method thereof. The material comprises MgAl2O4 ceramic and MgAl2O4 ceramic composite sintering reducer, the MgAl2O4 ceramic is formed by pre-burning MgO and Al2O3; the composite sintering reducer is pre-burned by Li2CO3, H3BO3, SiO2, ZnO, and MgO to form Li2O-MgO-ZnO-B2O3-SiO2 glass, and the pre-burned MgAl2O4 ceramic and the Li2O-MgO-ZnO-B2O3-SiO2 glass are subjected to ball milling mixing according the mass ratio of 1:2, granulation, moulding, rubber discharging and sintering to prepare the low-dielectric constant high-quality factor LTCC microwave medium material. The microwave medium material has low dielectric constant (6-8), the high quality factor (is greater than or equal to 45000), the sintering temperature is 920 DEG C, the process is simple, and the microwave medium material has the advantages of easy industrial production and stable material performance.

The invention provides a high dielectric constant BaO-Ln2O3-TiO2 system microwave dielectric material and a preparation method of the high dielectric constant BaO-Ln2O3-TiO2 system microwave dielectric material. The high dielectric constant BaO-Ln2O3-TiO2 system microwave dielectric material is composed of a major component (namely, (Ba1-m-nMgmSrn)6-3X(Sm1-yNdy)8+2XTi18O54), a sintering aid and a modified dopant. The major component, namely the (Ba1-m-nMgmSrn)6-3X(Sm1-yNdy)8+2XTi18O54 is solid solution, wherein the X is equal to 0-0.02; Y is equal to 0-0.05; m is equal to 0.002-0.025; and n is equal to 0.05-0.03. The sintering aid comprises one of or a mixture of more than one of low-melting-point oxides of Bi2O3, B2O3, CuO, Li2O, ZnO, SiO2, and the like and low-melting-point glass dust. The modified dopant comprises different metallic oxides and carbonate, such as one of or the mixture of more than one of ZrO2, BaCO3, TiO2, MnO2, SrO, and the like. The microwave dielectric material finally prepared through reasonable formula, optimized synthesis and ball-milling process can be sintered in the temperature range of 1250 DEG C to 1330 DEG C. The produced microwave capacitor has excellent microwave dielectric properties, wherein epsilon r is equal to 100; Q*f is more than or equal to 5500GHZ(3.5-4.5GHZ); and tau f(-40 DEG C-25 DEG C/25 DEG C-125 DEG C) is less than or equal to 10PPM/DEG C.

The invention discloses a high-Q-value medium-dielectric-constant microwave dielectric ceramic and a preparation method thereof and relates to a microwave dielectric ceramic. According to the invention, a novel material system is adopted as follows: xCaTiO3-(1-x)LaGaO3 (x is 0.66-0.62) microwave dielectric ceramic is obtained by compounding a calcium titanate (CaTiO3) phase with a lanthanum gallate (LaGaO3) phase; the microwave dielectric ceramic comprises the following components by weight percent: 25-35% of CaCO3, 15-30% of TiO2, 20-35% of La2O3 and 10-25% of Ga2O3, wherein the purities of CaCO3 and TiO2 are more than or equal to 99.0%, and the purities of La2O3 and Ga2O3 are more than or equal to 99.9%. The high-Q-value medium-dielectric-constant microwave dielectric ceramic disclosed by the invention is good in microwave dielectric property, simple in production technical process and good in repeatability, can be widely applied to preparation of good-property microwave devices such as a dielectric resonator, a filter and a duplexer and meets the technical requirements of systems such as a communication base station.

The invention relates to magnesium titanate based composite ceramic sintered at low temperature and a preparation method thereof. The magnesium titanate based composite ceramic is composed of the material adopting the following general formula: 0.9 (Mg0.95Zn0.05)2(Ti0.8Sn0.2)O4-0.1(Ca0.8Sr0.2)TiO3-3.0wt%LiF-0.8wt%Fe2O3-xwt%V2O5, wherein x is between 0.5 and 3.0. The sintering temperature of the magnesium titanate based composite ceramic can be decreased to 900 to 975 DEGC, so that the defect of the large temperature coefficient of the resonant frequency of the ceramic material is overcome; and thus the temperature stability of the material is ensured. According to a preparation method, the adopted raw materials are abundant and low in cost, thereby being favorable for industrial production. The magnesium titanate based composite ceramic can be widely used for manufacturing microwave devices such as low-temperature co-fired ceramic systems, GPS (Global Positioning System) antennae, wave filters for wireless local area networks, multilayer dielectric resonators and the like.

The invention belongs to the technical field of electronic ceramic preparation and application, and particularly relates to a method for fine synthesis of a ternary MgO-Nb2O5-TiO2 system microwave dielectric ceramic by using a sol-gel method. The technical scheme comprises adopting a sol-gel method to finely synthesize a ternary MgO-Nb2O5-TiO2 system microwave dielectric ceramic, and specifically comprises: 1) preparing a citric acid aqueous solution of Mg ions; 2) preparing a citric acid aqueous solution of Ti ions and Nb ions; and 3) synthesizing a ternary MgTiNb2O8 microwave dielectric ceramic nanometer precursor, and preparing the ceramic. The ternary MgO-Nb2O5-TiO2 system microwave dielectric ceramic has significant advantages of low synthesis temperature, uniform ceramic particles, good ceramic particle dispersity, pure phase, nano-scale powder (particle size of about 50 nm), high specific surface energy, high activity and the like. In addition, compared with the conventional solid-phase method, the method of the present invention has the following characteristics that: the sintering temperature can be significantly reduced by 100-200 DEG C so as to achieve low temperature sintering, maintain the good microwave dielectric property, and meet the LTCC application requirements.

The invention belongs to the field of new materials and microwave communication, and in particular, relates to an STLA microwave dielectric ceramic material and a preparation method and an application thereof. The STLA microwave dielectric ceramic material has main crystal structure of a perovskite structure, and has the chemical expression of aSrO-bTiO2-cCaO-d/2Ln2O3-e/2Al2O3, wherein Ln is at least one of rare earths La, Nd and Sm. The preparation method comprises the steps: according to the stoichiometric ratio of the main crystal phase structure, taking strontium carbonate, titanium dioxide, calcium carbonate, rare earth oxide and aluminum oxide, and sanding to mix the raw materials uniformly; then carrying out spray drying, and pre-sintering; smashing, adding a modification additive or adding no modification additive, and again sanding to mix uniformly; carrying out spray granulation, sieving, and carrying out compression molding; and finally, sintering to obtain the STLA microwave dielectric ceramic material. The microwave dielectric ceramic material can be applied to the fields of new materials, microwave communication and the like.

The present invention relates to low temperature sintered microwave dielectric ceramic with high dielectric constant and its preparation process. The preparation process includes mixing material including Li2CO3, Nb2O5 and alcohol, stoving, calcining, adding V2O5 and self-made ZnO-B2O3-SiO2 glass, mixing, drying, pressing into disc and sintering. The present invention features the sintering temperature lowered through the synergistic effect of V2O5 and ZnO-B2O3-SiO2 glass, regulated temperature coefficient of material frequency, improved powder and slurry characteristic, excellent co-sintering matching property with silver electrode, good microwave dielectric performance obtained through sintering at about 900 deg.c and stable technological process. The low temperature sintered microwave dielectric ceramic material may be used in various kinds of microwave devices.

The invention belongs to the technical field of electronic materials and devices, and discloses a tunable dielectric barium strontium titanate based composite silicate ceramic dielectric material and preparation thereof. The tunable dielectric barium strontium titanate based composite silicate ceramic dielectric material has a component formula of (1-m%)Ba1-zSrzTiO3+m%(Sr1-xAx)2(Zn1-yBy)Si2O7, wherein A is selected from Ba or Ca; B is selected from Co, Mg, Mn or Ni; the numerical value range of x is not smaller than 0 and not more than 1; the numerical value range of y is not smaller than 0 and not more than 1; the numerical value range of z is not smaller than 0.4 and not more than 0.6; and the numerical value range of m% is more than 0wt% and smaller than 100wt%. The tunable dielectric barium strontium titanate based composite silicate ceramic dielectric material of the invention is high in Q (Quality) value, low in dielectric constant and high in dielectric tunable rate, and can bewidely applied to preparation of tunable microwave elements and devices such as electric tuning microwave tuners, filters, microwave dielectric antennae and the like.

The invention provides a low temperature co-fired ceramic material. The low temperature co-fired ceramic material comprises the following components: 79-95wt% of ceramics and 5-21wt% of firing aiding glass. Compared with existing ceramic materials, the low temperature co-fired ceramic material has the beneficial effects that BaO, ZnO and TiO2 components are used as the raw materials of the ceramics; the ceramics formed by BaO and TiO2 have excellent microwave dielectric properties but have higher sintering temperatures; the sintering temperatures of the ceramics can be obviously reduced through addition of ZnO, so that the ceramics with better dielectric properties and lower sintering temperatures are obtained; the firing aiding glass has lower sintering temperature and part of atoms in the firing aiding glass are the same as or similar to part of atoms in a ceramic matrix; and meanwhile, the low temperature co-fired ceramic material with middle dielectric constant is obtained by controlling the contents of the ceramics and the firing aiding glass.

The ceramic material for microwave ceramic capacitor has the composition of MgTiO3-CaTiO3, and may be expressed in xMgTiO3-(1-x)CaTiO3, with x being 0.9-1.0. The preparation process includes: mixing basic magnesium carbonate, calcium carbonate and diboron pentoxide in certain proportion, ball milling, stoving, sieving and pre-sintering to obtain fused block; secondary ball milling, stoving, pelletizing, pressing to form and sintering to obtain the ceramic material. The ceramic material for microwave ceramic capacitor has excellent microwave dielectric performance and low cost.

This invention relates to a composite microwave medium ceramic material-Li2O-Nb2O5-TiO2 series material. It is composed of Li2TiO3 sosoloid (Li2TiO3ss phase) and M-phase sosoloid. The compositions are: xLi1+a-bNb1-a-3bTia+4bO3+(1-x)Li2+dNb3dTi1-4dO3, wherein: 0<x<1,0.05<a<0.2, 0<b<0.18,0<d<0.2; this inventive material is obtained by traditional preparation method. This inventive product has lower sintering temperature (1100deg.C), excellent microwave medium properties, adjustable dielectric constant (epsilon r=18-70), low resonant frequency temperature coefficient.

The invention discloses high-permittivity microwave dielectric ceramics capable of being sintered at medium-low temperature and a preparation method thereof. The ceramic material is a composite ceramic material whose main component is composited by (Ca0.8Sr0.2)x(Li0.5Sm0.5)(1-x)TiO3 and any of bi-based compounds Bi4B2O9, Bi2W2O9 and Bi2MoO6 sintering agents. The implementation method comprises the steps that (Ca0.8Sr0.2)x(Li0.5Sm0.5)(1-x)TiO3 powder as well as Bi4B2O9, Bi2W2O9 and Bi2MoO6 sintering agents are synthesized firstly; the (Ca0.8Sr0.2)x(Li0.5Sm0.5)(1-x)TiO3 powder is mixed and ball-milled with any of the Bi4B2O9, Bi2W2O9 and Bi2MoO6 sintering agents; and then the mixed powder containing the sintering agent is compressed into a cylindrical blank body and is subjected to heat preservation for 4 hours at 900 DEG C-1050 DEG C for presintering, so that the high-permittivity (Ca0.8Sr0.2)x(Li0.5Sm0.5)(1-x)TiO3 microwave dielectric ceramics which can be sintered at medium-low temperature and contain the sintering agent. The ceramic material has higher permittivity, smaller resonance temperature coefficient and moderate loss; performance tests prove that better microwave dielectric performances can be obtained: the permittivity Epsilonr is larger than 95, the absolute value of the resonance temperature coefficient Tauf is smaller than 50 ppm/DEG C, the quality factor Qf is larger than 1,500 GHz, the best sintering temperature is lower than 1,050 DEG C, and the 900-DEG C optimum sintering can be achieved; and the whole preparation technology for the microwave dielectric ceramics is relatively simple, stable and easy to implement.

The invention discloses an ultra-low temperature sintering microwave dielectric ceramic material system, and a preparation method and application thereof. A structural general expression of the systemis Na2WxO3x+1 (x=1, 2, 4). The system can be sintered at a very low temperature (565 to 740 DEG C) and has excellent microwave dielectric properties (dielectric constant between 5 and 12, quality factor Qf between 10,000 GHz and 124,200 GHz, and temperature coefficient of frequency -60 ppm/DEG C to -80 ppm/DEG C). Powder preparation is carried out by an improved solid phase method, and calciningtemperature is 400 to 550 DEG C. The material system can be co-fired with Ag or Al electrodes and can be used to prepare low-temperature co-fired ceramic (LTCC) substrates for use in microwave resonators, filters, and panel antennas. The ceramic material system meets the requirements of environmental protection, and is non-toxic and pollution-free.

The invention provides a microwave medium ceramic material and a preparing method thereof. The microwave medium ceramic material is composed of principal crystalline phases and property-modifying additives, wherein the structural formula of the principal crystalline phases is Zrx(ZnyNb1-y) 1-xTiO4, 0.2<=x<=0.7, 1/3<=y<=2/3, and the property-modifying additives are mixture of any one or more than two of MnO2, CeO2 and Ga2O3. The preparing method of the material includes the following steps of burdening, ball-milling, presintering, property-modifying additive adding and ball-milling, prilling, compression moulding, and sintering. The microwave medium ceramic material is low in sintering temperature, and good in microwave dielectricity, has the middle dielectric constant, the high Q and the adjustable frequency temperature factor, can meet development requirements of microwave device miniaturization and high frequency, and can be used for manufacturing medium resonators, filters, oscillators and other microwave devices in communication systems.

The invention discloses a Li2MoO4-Mg2SiO4-based composite ceramic microwave material and a preparation method thereof. A chemical general formula of the composite ceramic can be written as xLi2MoO4-(1-x)Mg2SiO4, wherein x=10 wt%, 50 wt%, 70 wt%, 80 wt%, 85 wt%, 90 wt% or 95 wt%. The method comprises the following steps: firstly weighing magnesium oxide and silicon dioxide according to a certain stoichiometric ratio, performing ball milling for uniformization, performing drying, and performing pre-sintering to obtain Mg2SiO4; and weighing the prepared Mg2SiO4 and a Li2MoO4 raw material according to a certain weight ratio, adding 15 wt% of deionized water, performing uniform mixing, performing heat pressing on the mixture at 200 DEG C and 500 MPa for 60 min, and performing drying at 120 DEGC for 24 h to remove residual water to obtain the ultra-low-temperature cold sintered xLi2MoO4-(1-x)Mg2SiO4 composite ceramic material. Compared with traditional high-temperature solid-phase sintering(often higher than 1000 DEG C or more), the method provided by the invention has a sintering temperature in the range from room temperature to 200 DEG C; and the method provided by the invention hasa simple process, saves energy and can be widely applied to production of Li2MoO4-Mg2SiO4 composite ceramic substrates.

The invention discloses a microwave dielectric ceramics with lower sintering temperature, comprising the component of (Mg [1-x] Sn[X]) TiO3, wherein X ranges from 0.03 to 0.08, and the content of the raw materials according to molar percentage is as follows: 50 percent of TiO2, 40 to 50 percent of MgO and 0 to 10 percent of SnO2. The solid phase synthesis technology is adopted and includes the following steps: (1) material preparation; (2) calcination at 1100 DEG C, precursor synthesis, ball milling and drying; and (3) blank preparation and sintering at 1150 to 1250 DEG C. The invention uses Sn[2+] ion to partially replace Mg[2+] ion, thereby improving the microwave dielectric property of MgTiO3 ceramic, reducing the sintering temperature (1150 to 1250 DEG C)of the system, and realizing dense sintering at a lower temperature; and the preparation technology is simple, and the preparation process does not cause pollution.

The invention relates to a microwave dielectric ceramic, comprising a main crystal phase. A chemical formula of the main crystal phase is Mg<2-2x>CaTiO<4-x>, wherein x is equal to or larger than 0.05 but smaller than or equal to 0.2. The microwave dielectric ceramic has relatively good microwave dielectric properties. Besides, the invention provides a preparation method of the microwave dielectric ceramic.

The invention discloses an ultralow-temperature-sintered composite microwave dielectric ceramic material and a preparation method thereof. The formula of the ceramic material is (Ag0.5Bi0.5)(MoxW1-x)O4, wherein 0.3<=x<=0.7. The ultralow-temperature-sintered composite microwave dielectric ceramic material has the characteristics of finely adjustable relative dielectric constant (32.2-34.5), favorable microwave behavior microwave dielectric ceramics (Qf=11500GHz-12000GHz), adjustable temperature coefficient of resonance frequency (-32ppm/DEG C to +19ppm/DEG C) and simple chemical composition. By adopting the solid-phase reaction sintering method, the invention is simple in technological operation, environment-friendly and suitable for industrial production.

The invention discloses temperature-stable type low-loss microwave dielectric ceramic. The target composition expression of the temperature-stable type low-loss microwave dielectric ceramic is 0.99(0.95(Mg0.97Zn0.03)TiO3-0.05CaTiO3)-0.01LaAlO3. Firstly, MgO, TiO2, CaCO3 and ZnO are mixed according to the stoichiometry equation 0.95(Mg0.97Zn0.03)TiO3-0.05CaTiO3, and presintering is carried out at 900-1150 DEG C after ball milling, drying and screening are carried out; secondly, La2O3 and Al2O3 are mixed according to the stoichiometry equation LaAlO3, and presintering is carried out at 1100-1300 DEG C after ball milling, drying and screening are carried out; thirdly, the two kinds of powder obtained after presintering are mixed according to the mole ratio of 99:1 and pressed into a green body after ball milling, drying, screening and pelleting are carried out, the green body is sintered at 1150 DEG C-1250 DEG C, and the temperature-stable type low-loss microwave dielectric ceramic is prepared. The QF value of the temperature-stable type low-loss microwave dielectric ceramic reaches 55,000-88,500 GHz, and the temperature coefficient (tao f) of resonance frequency reaches -9.9--6.9*10<-6>/DEG C. The temperature-stable type low-loss microwave dielectric ceramic is simple in preparing technology and superior in microwave dielectric performance, saves energy cost, conforms to the low-carbon environment-friendly concept and has wide application prospects.