High dielectric constant microwave dielectric ceramic material, preparation method and application thereof

Abstract

The application discloses a high-dielectric-constant microwave dielectric ceramic material, and a preparation method and application thereof. The microwave dielectric ceramic material has the following composition expression: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, wherein 17%<=a<=19%, 78%<=b<=80%, 1%<=c<=2%, 0.1%<=d<=0.2%, 0.1%<=e<=0.2%, 0.1%<=f<=0.2%, 0.1%<=g<=0.2%, 0.1%<=h<=0.2%, and 0.1%<=i<=0.2%. The microwave dielectric ceramic material has the following microwave performance: Er=43+ / -2, Qf>=20000GHz, and a resonance frequency temperature coefficient is within + / -5ppm / degree Celsius, and can be applied to a vehicle navigation ceramic antenna, and has important industrial application value.

Description

Technical Field

[0001] This invention belongs to the field of electronic information materials technology, specifically relating to a high dielectric constant microwave dielectric ceramic material, its preparation method, and its application. Background Technology

[0002] With the completion of GPS and BeiDou navigation satellite systems, the frequency values ​​and frequency bands of corresponding satellite positioning signals have expanded rapidly. Essentially, both GPS and BeiDou systems require multiple frequencies for high-frequency use to meet the ever-increasing navigation and positioning demands. As the front end of the satellite signal receiver, the ceramic satellite antenna plays a crucial role, performing signal reception, amplification, and transmission. As the front-end processing component for satellite signals, the requirements for the microwave dielectric ceramic materials used in ceramic antennas are becoming increasingly stringent.

[0003] Currently, commercially available materials used in the industry for signal filtering, with a dielectric constant range of 43±2, are mainly applied to ceramic antennas with specifications of 18*18~20*20 (thickness depends on the specific design). Their temperature coefficient is generally greater than ±15ppm / ℃. In special operating environments, such as high-temperature or cold regions, the antenna receiving center frequency value will deviate significantly due to the large temperature coefficient, resulting in weak satellite signal reception or even connection interruption.

[0004] Therefore, achieving a ceramic dielectric material with a dielectric constant of 40±5, a Qf value ≥20000, and a temperature coefficient within ±5ppm / ℃ is a promising development direction for microwave dielectric ceramic materials used in automotive navigation ceramic antennas. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a high dielectric constant microwave dielectric ceramic material, its preparation method, and its applications. This microwave dielectric ceramic material can maintain the following microwave properties under sintering conditions of (1300~1340℃): Er=43±2, Qf≥20000GHz, and the resonant frequency temperature coefficient τf is adjustable and meets the requirement of ±5ppm / ℃. It can meet the technical requirements of signal reception and transmission in satellite navigation and communication, and has significant industrial application value.

[0006] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0007] This invention provides a high dielectric constant microwave dielectric ceramic material with the following composition expression: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages and satisfy the following conditions: 17%≤a≤19%, 78%≤b≤80%, 1%≤c≤2%, 0.1%≤d≤0.2%, 0.1%≤e≤0.2%, 0.1%≤f≤0.2%, 0.1%≤g≤0.2%, 0.1%≤h≤0.2%, and 0.1%≤i≤0.2%.

[0008] Furthermore, this microwave dielectric ceramic comprises two main crystalline phases and three auxiliary crystalline phases. The two main crystalline phases are BaTi4O9 and Sm2Ti2O7, and the three auxiliary crystalline phases are BaSiO3, Li2BaTi6O3, and Li2BaTi6O3. 14 Li2TiO3.

[0009] Furthermore, the dielectric constant of this microwave dielectric ceramic material is 41–45, the quality factor Q×f is above 20000 GHz, and the absolute value of the temperature coefficient of the resonant frequency is below 5 ppm / ℃.

[0010] Another aspect of the present invention provides a method for preparing a high dielectric constant microwave dielectric ceramic material, comprising the following steps:

[0011] 1) Weigh BaCO3, TiO2, Sm2O3, WO3, ZrO2, MnO2, Li2CO3, SiO2, and Sb2O3 according to the molar percentage of each composition. Mix the weighed materials thoroughly and then ball mill them. After ball milling, dry and sieve them and place them in an alumina crucible. Then keep them warm and pre-fire them to obtain the powder base material.

[0012] 2) The powder substrate obtained in step 1) above is fully ball-milled, and then dried, granulated and sieved.

[0013] 3) Press the granules after sieving in step 2) into shape, and finally sinter them to obtain the high dielectric constant microwave dielectric ceramic material.

[0014] Furthermore, the temperature of the heat preservation and preheating process in step 1) is 800-1100℃, and the heat preservation and preheating time is 3-5h.

[0015] Furthermore, the sintering process in step 3) is carried out at 1300–1340°C for 3–8 hours.

[0016] Furthermore, the granulation described in step 2) involves mixing the dried powder with a binder and then forming micron-sized spherical particles.

[0017] Furthermore, the adhesive is selected from at least one of polyvinyl alcohol solution, polyvinyl butyral solution, acrylic acid solution, or methylcellulose.

[0018] Furthermore, in step 3), the granules are pressed into cylinders with a diameter of 10 mm and a height of 6 mm.

[0019] This invention also provides the application of this high dielectric constant microwave dielectric ceramic material in vehicle navigation ceramic antennas.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The microwave dielectric ceramic of this invention is sintered from BaCO3, TiO2, Sm2O3, WO3, ZrO2, MnO2, Li2CO3, SiO2, and Sb2O3. This invention involves doping the microwave dielectric ceramic with Li, Zr, Si, and Sb, wherein the doping of Li and Si primarily forms auxiliary crystal phases BaSiO3 and Li2BaTi6O3. 14 The doping of Li₂TiO₃ and Zr involves equivalent doping at the Ti sites to enhance the strength of the ceramic body. BaSiO₃ is a phase with a negative frequency temperature coefficient, and Li₂BaTi₆O₃... 14 The Li2TiO3 phase has a positive frequency temperature coefficient, and these auxiliary crystal phases can be well integrated with the main crystal without affecting the dielectric constant and quality factor of the main crystal phase. Furthermore, the temperature coefficient can be adjusted by regulating the amount of auxiliary crystal phases.

[0022] The microwave dielectric ceramic of the present invention can maintain the following microwave performance under sintering conditions of (1300~1340℃): Er=43±2, Qf≥20000GHz, and the resonant frequency temperature coefficient τf is adjustable and meets the requirement of ±5ppm / ℃. It can meet the technical requirements of signal reception and transmission in satellite navigation communication, and can be applied to vehicle navigation ceramic antennas, which has important industrial application value. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] This invention provides a high dielectric constant microwave dielectric ceramic material with the following composition expression: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages and satisfy the following conditions: 17%≤a≤19%, 78%≤b≤80%, 1%≤c≤2%, 0.1%≤d≤0.2%, 0.1%≤e≤0.2%, 0.1%≤f≤0.2%, 0.1%≤g≤0.2%, 0.1%≤h≤0.2%, and 0.1%≤i≤0.2%.

[0025] This microwave dielectric ceramic comprises two main crystalline phases and three auxiliary crystalline phases. The two main crystalline phases are BaTi4O9 and Sm2Ti2O7, and the three auxiliary crystalline phases are BaSiO3, Li2BaTi6O3, and Li2BaTi6O3. 14 Li2TiO3.

[0026] The dielectric constant of this microwave dielectric ceramic material is 41-45, the quality factor Q×f is above 20000 GHz, and the absolute value of the temperature coefficient of the resonant frequency is below 5 ppm / ℃.

[0027] The preparation method of this high dielectric constant microwave dielectric ceramic material includes the following steps:

[0028] 1) Weigh BaCO3, TiO2, Sm2O3, WO3, ZrO2, MnO2, Li2CO3, SiO2, and Sb2O3 according to the molar percentage of each composition. Mix the weighed materials thoroughly and then ball mill them. After ball milling, dry and sieve them and place them in an alumina crucible. Then, pre-calcine them at a temperature of 800-1100℃ for 3-5 hours to obtain the powder substrate.

[0029] 2) The powder substrate obtained in step 1) above is fully ball-milled, dried, granulated, and sieved after ball milling; wherein, granulation is to mix the dried powder with a binder and then make micron-sized spherical particles; the binder is selected from at least one of polyvinyl alcohol solution, polyvinyl butyral solution, acrylic acid solution or methylcellulose;

[0030] 3) Press the granules after sieving in step 2) into cylinders with a diameter of 10 mm and a height of 6 mm, and finally sinter them at 1300-1380℃ for 3-8 hours to obtain the microwave dielectric ceramic material.

[0031] This high dielectric constant microwave dielectric ceramic material can be used in vehicle navigation ceramic antennas.

[0032] The following embodiments will further illustrate the present invention, but are not intended to limit the invention.

[0033] Example 1

[0034] The high dielectric constant microwave dielectric ceramic material of Example 1 has the following composition formula: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages: a = 19.0%, b = 79.4%, c = 1%, d = 0.1%, e = 0.1%, f = 0.1%, g = 0.1%, h = 0.1%, and i = 0.1%.

[0035] The preparation method of this high dielectric constant microwave dielectric ceramic material includes the following steps:

[0036] 1) Weigh BaCO3, TiO2, Sm2O3, WO3, ZrO2, MnO2, Li2CO3, SiO2, and Sb2O3 according to the molar percentage of each composition. Mix the weighed materials thoroughly and then ball mill them. After ball milling, dry and sieve them and place them in an alumina crucible. Then, pre-calcine them at 1000℃ for 4 hours to obtain the powder substrate.

[0037] 2) The powder substrate obtained in step 1) above is fully ball-milled, and then dried, granulated and sieved.

[0038] 3) Press the granules after sieving in step 2) into cylinders with a diameter of 10 mm and a height of 6 mm, and finally sinter them at 1320℃ for 5 h to obtain the microwave dielectric ceramic material.

[0039] Example 2

[0040] The high dielectric constant microwave dielectric ceramic material of Example 2 has the following composition expression: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages: a = 18.4%, b = 80.0%, c = 1.0%, d = 0.1%, e = 0.1%, f = 0.1%, g = 0.1%, h = 0.1%, and i = 0.1%.

[0041] The preparation method of this high dielectric constant microwave dielectric ceramic material includes the following steps:

[0042] 1) Weigh BaCO3, TiO2, Sm2O3, WO3, ZrO2, MnO2, Li2CO3, SiO2, and Sb2O3 according to the molar percentage of each composition. Mix the weighed materials thoroughly and then ball mill them. After ball milling, dry and sieve them and place them in an alumina crucible. Then, pre-calcine them at 1000℃ for 4 hours to obtain the powder substrate.

[0043] 2) The powder substrate obtained in step 1) above is fully ball-milled, and then dried, granulated and sieved.

[0044] 3) Press the sieving granules from step 2) into cylinders with a diameter of 10 mm and a height of 6 mm, and finally sinter them at 1340℃ for 5 h to obtain the microwave dielectric ceramic material.

[0045] Example 3

[0046] The high dielectric constant microwave dielectric ceramic material of Example 3 has the following composition expression: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages: a = 17.4%, b = 80.0%, c = 2.0%, d = 0.1%, e = 0.1%, f = 0.1%, g = 0.1%, h = 0.1%, and i = 0.1%.

[0047] The difference between the preparation method of Example 3 and Example 1 is that the sintering temperature in step 3) is 1340℃.

[0048] Example 4

[0049] The high dielectric constant microwave dielectric ceramic material of Example 4 has the following composition expression: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages: a = 18.3%, b = 80.0%, c = 1.0%, d = 0.2%, e = 0.1%, f = 0.1%, g = 0.1%, h = 0.1%, and i = 0.1%.

[0050] The difference between the preparation method of Example 4 and Example 1 is that the sintering temperature in step 3) is 1340℃.

[0051] Example 5

[0052] The high dielectric constant microwave dielectric ceramic material of Example 5 has the following composition formula: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages: a = 19.0%, b = 79.3%, c = 1.0%, d = 0.1%, e = 0.2%, f = 0.1%, g = 0.1%, h = 0.1%, and i = 0.1%.

[0053] The preparation method of Example 5 is the same as that of Example 1.

[0054] Example 6

[0055] The high dielectric constant microwave dielectric ceramic material of Example 6 has the following composition formula: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages: a = 18.9%, b = 79.4%, c = 1.0%, d = 0.1%, e = 0.1%, f = 0.2%, g = 0.1%, h = 0.1%, and i = 0.1%.

[0056] The difference between the preparation method of Example 6 and Example 1 is that the sintering temperature in step 3) is 1300℃.

[0057] Example 7

[0058] The high dielectric constant microwave dielectric ceramic material of Example 7 has the following composition formula: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages: a = 18.8%, b = 79.5%, c = 1.0%, d = 0.1%, e = 0.1%, f = 0.1%, g = 0.2%, h = 0.1%, and i = 0.1%.

[0059] The difference between the preparation method of Example 7 and Example 1 is that the sintering temperature in step 3) is 1300℃.

[0060] Example 8

[0061] The high dielectric constant microwave dielectric ceramic material of Example 8 has the following composition expression: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages: a = 18.7%, b = 79.6%, c = 1.0%, d = 0.1%, e = 0.1%, f = 0.1%, g = 0.1%, h = 0.2%, and i = 0.1%.

[0062] The difference between the preparation method of Example 8 and Example 1 is that the sintering temperature in step 3) is 1300℃.

[0063] Example 9

[0064] The high dielectric constant microwave dielectric ceramic material of Example 9 has the following composition formula: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, where a, b, c, d, e, f, g, h, and i independently represent molar percentages: a = 18.6%, b = 79.7%, c = 1.0%, d = 0.1%, e = 0.1%, f = 0.1%, g = 0.1%, h = 0.1%, and i = 0.2%.

[0065] The difference between the preparation method of Example 9 and Example 1 is that the sintering temperature in step 3) is 1300℃.

[0066] Comparative Example 1

[0067] The microwave dielectric ceramic material of Comparative Example 1 has the following composition expression: aBaCO3-bTiO2-cSm2O3, where a, b, and c represent molar percentages, a = 15%, b = 80%, and c = 5%.

[0068] The method for preparing this microwave dielectric ceramic material includes the following steps:

[0069] 1) Weigh BaCO3, TiO2, and Sm2O3 according to the molar percentage of each composition. Mix the weighed materials thoroughly and then ball mill them. After ball milling, dry and sieve them and place them in a corundum crucible. Then, pre-calcine them at 1000℃ for 4 hours to obtain the powder substrate.

[0070] 2) The powder substrate obtained in step 1) above is fully ball-milled, and then dried, granulated and sieved.

[0071] 3) Press the sieving granules from step 2) into cylinders with a diameter of 10 mm and a height of 6 mm, and finally sinter them at 1300℃ for 5 h to obtain the microwave dielectric ceramic material.

[0072] Comparative Example 2

[0073] The microwave dielectric ceramic material of Comparative Example 2 has the following composition expression: aBaCO3-bTiO2-cSm2O3, where a, b, and c represent molar percentages, a = 20%, b = 75%, and c = 5%.

[0074] The method for preparing this microwave dielectric ceramic material includes the following steps:

[0075] 1) Weigh BaCO3, TiO2, and Sm2O3 according to the molar percentage of each composition. Mix the weighed materials thoroughly and then ball mill them. After ball milling, dry and sieve them and place them in a corundum crucible. Then, pre-calcine them at 1000℃ for 4 hours to obtain the powder substrate.

[0076] 2) The powder substrate obtained in step 1) above is fully ball-milled, and then dried, granulated and sieved.

[0077] 3) Press the granules after sieving in step 2) into cylinders with a diameter of 10 mm and a height of 6 mm, and finally sinter them at 1320℃ for 5 h to obtain the microwave dielectric ceramic material.

[0078] Comparative Example 3

[0079] The microwave dielectric ceramic material of Comparative Example 3 has the following composition expression: aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2, where a, b, c, d, e, and f represent molar percentages, a = 15%, b = 80%, c = 2%, d = 1%, e = 1%, and f = 1%.

[0080] The method for preparing this microwave dielectric ceramic material includes the following steps:

[0081] 1) Weigh BaCO3, TiO2, Sm2O3, WO3, ZrO2 and MnO2 according to the molar percentage of each composition. Mix the weighed materials thoroughly and then ball mill them. After ball milling, dry and sieve them and put them into a corundum crucible. Then, pre-calcine them at 1000℃ for 4 hours to obtain the powder base material.

[0082] 2) The powder substrate obtained in step 1) above is fully ball-milled, and then dried, granulated and sieved.

[0083] 3) Press the sieving granules from step 2) into cylinders with a diameter of 10 mm and a height of 6 mm, and finally sinter them at 1340℃ for 5 h to obtain the microwave dielectric ceramic material.

[0084] Performance testing

[0085] The microwave dielectric properties of microwave dielectric ceramics obtained by testing them using a microwave network analyzer are shown in Table 1.

[0086] Table 1 shows the parameter values ​​for the examples and comparative examples, as well as the microwave dielectric properties of the microwave dielectric ceramics.

[0087]

[0088] As shown in Table 1, compared with the microwave dielectric ceramic materials of Comparative Examples 1-3, the microwave dielectric ceramic materials of Examples 1-9 of the present invention can maintain the following microwave performance under sintering conditions of (1300~1340℃): Er=43±2, Qf≥20000GHz, and the temperature coefficient of resonant frequency τf is within ±5ppm / ℃. They can meet the technical requirements of signal reception and transmission in satellite navigation communication, and can be applied to vehicle navigation ceramic antennas, which have important industrial application value.

[0089] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any modifications or equivalent transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A high dielectric constant microwave dielectric ceramic material, characterized by: The composition expression is aBaCO3-bTiO2-cSm2O3-dWO3-eZrO2-fMnO2-gLi2CO3-hSiO2-iSb2O3, wherein a, b, c, d, e, f, g, h, and i independently represent molar percentages, and satisfy the following conditions: 17%≤a≤19%, 78%≤b≤80%, 1%≤c≤2%, 0.1%≤d≤0.2%, 0.1%≤e≤0.2%, 0.1%≤f≤0.2%, 0.1%≤g≤0.2%, 0.1%≤h≤0.2%, and 0.1%≤i≤0.2%. The microwave dielectric ceramic comprises two main crystal phases and three auxiliary crystal phases, the two main crystal phases are BaTi4O9 and Sm2Ti2O7, and the three auxiliary crystal phases are BaSiO3, Li2BaTi6O14 and Li2TiO3.

2. The high dielectric constant microwave dielectric ceramic material of claim 1, wherein: The microwave dielectric ceramic material has a dielectric constant of 41-45, a quality factor Qxf value of more than 20000 GHz, and an absolute value of a resonance frequency temperature coefficient of less than 5 ppm / ℃.

3. A method of producing the high dielectric constant microwave dielectric ceramic material according to any one of claims 1 to 2, characterized by, The method comprises the following steps: 1) BaCO3, TiO2, Sm2O3, WO3, ZrO2, MnO2, Li2CO3, SiO2 and Sb2O3 are weighed according to the molar percentages of each composition, and then mixed and ball milled, and the ball milled material is dried, sieved, placed in a corundum crucible, and then heat treated and pre-fired to obtain a powder base material; 2) the powder base material obtained in step 1) is ball milled, dried, granulated and sieved; 3) the granulated material sieved in step 2) is pressed into a shape, and finally sintered to obtain the high dielectric constant microwave dielectric ceramic material.

4. The method of claim 3, wherein the high dielectric constant microwave dielectric ceramic material is prepared by the steps of: preparing a mixed powder of the first and second powders; and sintering the mixed powder. The heat treatment and pre-firing process in step 1) is at a temperature of 800-1100℃ for 3-5h.

5. The method of claim 3, wherein the high dielectric constant microwave dielectric ceramic material is prepared by the steps of: preparing a mixed powder of the first and second powders; and sintering the mixed powder. The sintering process in step 3) is sintering at 1300-1340℃ for 3-8h.

6. The method of claim 3, wherein the high dielectric constant microwave dielectric ceramic material is prepared by the steps of: preparing a mixed powder of the first and second powders; and mixing the mixed powder with the third powder. The granulation in step 2) is mixing the dried powder with a binder, and then making micron-sized spherical particles.

7. The method of claim 6, wherein the high dielectric constant microwave dielectric ceramic material is prepared by the steps of: mixing a BaTi04 powder, a Bi2O3 powder, a B2O3 powder, and a Li2O powder; and sintering the mixture. The binder is at least one selected from polyvinyl alcohol solution, polyvinyl butyral solution, acrylic acid solution or methyl cellulose.

8. The method for preparing high dielectric constant microwave dielectric ceramic material according to claim 3, characterized in that, In step 3), the granulated material is pressed into a cylinder with a diameter of 10mm and a height of 6mm.

9. Application of the high dielectric constant microwave dielectric ceramic material in claim 1-2 to a ceramic antenna for vehicle navigation.

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