A low-loss microwave dielectric ceramic and a preparation method thereof

Abstract

The present invention provides a low-loss microwave dielectric ceramic and a preparation method thereof, belonging to the technical field of electronic ceramics. The composition expression of the low-loss microwave dielectric ceramic provided by the present invention is ZnTi 1‑ x Sc x Nb2O8, wherein x is 0.05-0.15. The low-loss microwave dielectric ceramic provided by the present invention has low dielectric loss, that is, has a high Qf value.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic ceramics, and in particular to a low-loss microwave dielectric ceramic and a preparation method thereof. Background Art

[0002] With the large-scale deployment of 5G base stations, 5G base station antennas have been gradually upgraded from 4 and 8 channels in the 4G era to 32 and 64 channels. Since each channel requires a complete set of RF units to receive and send uplink and downlink signals, and the corresponding filters are used for signal processing, the demand for passive components such as dielectric filters and dielectric resonators has increased significantly, but the problem of system power consumption has become increasingly prominent. In the total power consumption of the system, passive components account for more than 40%, and the low loss of passive components can be attributed to the design and development of low-loss microwave dielectric ceramics. Therefore, reducing the loss of microwave dielectric ceramic materials is one of the effective ways to solve the power consumption problem.

[0003] For microwave dielectric ceramics, low dielectric loss represents a high Qf value under the premise that the resonant frequency does not change much. The present invention adopts a solid phase reaction method to prepare low-loss ZnTi by adjusting the raw material ratio. 1-x Sc x Nb2O8 microwave dielectric ceramics were prepared and their microwave dielectric properties were tested. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a low-loss microwave dielectric ceramic and a preparation method thereof. The low-loss microwave dielectric ceramic provided by the present invention has a high Qf value, that is, low dielectric loss.

[0005] In order to achieve the above object, the present invention provides the following technical solution: a low-loss microwave dielectric ceramic, whose composition expression is ZnTi 1-x Sc x Nb2O8, wherein x is 0.05-0.15, preferably 0.05, 0.1, 0.15.

[0006] The present invention also provides a method for preparing the low-loss microwave dielectric ceramic described in the above technical solution, comprising the following steps:

[0007] 1) ZnO, TiO2, Sc2O3, Nb2O5 are mixed according to the chemical formula ZnTi 1-x Sc x Weigh the required raw materials, mix the weighed materials, ball mill, dry, crush, sieve, and then pre-sinter to preliminarily synthesize ZnTi 1-x Sc x Nb2O8 microwave dielectric ceramic powder;

[0008] 2) adding polyvinyl alcohol to the powder obtained in step 1), ball milling, drying, crushing, sieving, and pressing into a cylindrical ceramic green body using an electric tablet press;

[0009] 3) Sintering the ceramic green body obtained in step 2) at 1120-1160° C. for 4-8 hours to obtain a low-loss microwave dielectric ceramic. In some implementation cases, the sintering temperature is 1140° C.

[0010] Preferably, the ball milling in step 1) further comprises adding zirconium oxide balls and deionized water for ball milling; the ball milling speed is 400 rpm, and the ball milling time is 5-8 h.

[0011] Preferably, the drying temperature in step 1) is 100° C. and the sieving is through a 40-mesh sieve.

[0012] Preferably, the pre-sintering temperature in step 1) is 900° C. and the pre-sintering time is 4-6 hours.

[0013] Preferably, the amount of polyvinyl alcohol added in step 2) is 1wt%-3wt% of the powder mass.

[0014] Preferably, the ball milling time in step 2) is 10-12 hours.

[0015] Preferably, the sieving in step 2) is through an 80-mesh sieve.

[0016] Preferably, in step 2), the ceramic green body has a diameter of 10 mm and a thickness of 5 mm.

[0017] Beneficial technical effects:

[0018] The present invention provides a low-loss microwave dielectric ceramic and a preparation method thereof. The present invention adopts a solid phase reaction method to prepare a low-loss microwave dielectric ceramic by adjusting the raw material ratio. The composition expression is ZnTi 1-x Sc x Nb2O8, wherein x is 0.05-0.15, the low-loss microwave dielectric ceramic provided by the present invention has low dielectric loss, that is, has a high Qf value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The ZnTi obtained in Example 1 0.95 Sc 0.05 XRD diffraction pattern of Nb2O8 microwave dielectric ceramics. DETAILED DESCRIPTION

[0020] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0021] Example 1

[0022] 1) ZnO, TiO2, Sc2O3, Nb2O5 are mixed according to the stoichiometric formula ZnTi 0.95 Sc 0.05 Nb2O8 is prepared, and the powder ratio is: ZnO 1.1443g, TiO2 1.0768g, Sc2O3 0.0245g, Nb2O5 3.7816g. The powder is put into a polyester tank, and after adding 300ml of deionized water and 60g of zirconium balls, a planetary ball mill is used for ball milling for 8 hours at a speed of 400 rpm and one-way operation. The milled slurry is transferred to a drying oven, dried at 100°C, crushed, and sieved with a 40-mesh sieve. The sieved powder is put into a sintering furnace, pre-sintered at 900°C, and kept warm for 6 hours.

[0023] 2) Add 2 wt % of polyvinyl alcohol to the powder pre-sintered in step 1, mix and put into a ball mill, add zirconium oxide balls and deionized water, ball mill for 12 hours, dry and grind, pass through an 80-mesh sieve, and press into a cylindrical green body with an electric tablet press at a pressure of 2 MPa;

[0024] 3) Sinter the green body at 1140℃ for 6 hours to make ZnTi 0.95 Sc 0.05 Nb2O8 microwave dielectric ceramics.

[0025] The obtained ZnTi 0.95 Sc 0.05 Nb2O8 microwave dielectric ceramics were characterized by XRD. Figure 1 It can be seen that after X-ray powder diffraction analysis, the phase composition of the ceramic is a typical manganese-tantalite structure, which matches the standard card PDF48-0323. In addition, no other redundant diffraction peaks were found, indicating that the introduction of Sc2O3 did not change the phase composition.

[0026] Example 2

[0027] Same as Example 1, except that ZnO, TiO2, Sc2O3, Nb2O5 are prepared according to the stoichiometric formula ZnTi 0.9 Sc 0.1 Nb2O8 is used for batching.

[0028] Example 3

[0029] Same as Example 1, except that ZnO, TiO2, Sc2O3, Nb2O5 are prepared according to the stoichiometric formula ZnTi 0.85 Sc 0.15 Nb2O8 is used for batching.

[0030] Comparative Example 1

[0031] Same as Example 1, except that ZnO, TiO2 and Nb2O5 are mixed according to the stoichiometric formula ZnTiNb2O8, and the sintering temperature is 1140°C.

[0032] The microwave dielectric properties of the microwave dielectric ceramics of Examples 1-3 and Comparative Example 1 were tested by a network analyzer. The test results are shown in Table 1.

[0033] Table 1 Microwave dielectric properties of Examples 1-3 and Comparative Example 1

[0034]

[0035] It can be seen from Table 1 that, compared with the microwave dielectric ceramic of Comparative Example 1, the microwave dielectric ceramics of Examples 1-3 of the present invention have more excellent microwave dielectric properties, with high Qf values, i.e., low dielectric loss. Among them, the microwave dielectric ceramic of Example 1 has the highest Qf value, i.e., the lowest dielectric loss.

[0036] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low-loss microwave dielectric ceramic, characterized in that: Its composition expression is ZnTi 1-x Sc x Nb2O8, where x is 0.05-0.

15.

2. The low-loss microwave dielectric ceramic according to claim 1, characterized in that: In the composition expression, x is 0.05, 0.1 or 0.

15.

3. The method for preparing the low-loss microwave dielectric ceramic according to any one of claims 1 to 2, characterized in that: The following steps are involved: 1) ZnO, TiO2, Sc2O3, Nb2O5 are mixed according to the chemical formula ZnTi 1-x Sc x Weigh the required raw materials, mix the weighed materials, ball mill, dry, crush, sieve, and then pre-sinter to preliminarily synthesize ZnTi 1-x Sc x Nb2O8 microwave dielectric ceramic powder; 2) adding polyvinyl alcohol to the powder obtained in step 1), ball milling, drying, crushing, sieving, and pressing into a cylindrical ceramic green body using an electric tablet press; 3) Sintering the ceramic green body obtained in step 2) at 1120-1160° C. for 4-8 hours to obtain a low-loss microwave dielectric ceramic.

4. The preparation method according to claim 3, characterized in that: Step 1) The ball milling further comprises adding zirconium oxide balls and deionized water for ball milling; the ball milling speed is 400 rpm, and the ball milling time is 5-8 hours.

5. The preparation method according to claim 3, characterized in that: Step 1) The drying temperature is 100° C. and the sieving is through a 40-mesh sieve.

6. The preparation method according to claim 3, characterized in that: Step 1) The pre-sintering temperature is 900° C. and the pre-sintering time is 4-6 hours.

7. The preparation method according to claim 3, characterized in that: Step 2) The amount of polyvinyl alcohol added is 1wt%-3wt% of the powder mass.

8. The preparation method according to claim 3, characterized in that: Step 2) The ball milling time is 10-12h.

9. The preparation method according to claim 3, characterized in that: The sieving in step 2) is through an 80-mesh sieve.

10. The preparation method according to claim 3, characterized in that: Step 2) The ceramic green body has a diameter of 10 mm and a thickness of 5 mm.

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