350-2000MHz high-pass filter

Abstract

The utility model discloses a 350-2000MHz high-pass filter, which comprises a 350-690MHz filter, a 690-1250MHz filter and a 1250-2000MHz filter which are connected in parallel, two sections are connected with a change-over switch after parallel connection, and each of the three filters comprises a porcelain body, a first inductor, a second inductor, a third inductor, a fourth inductor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and a fifth capacitor. A first capacitor, a second capacitor, a third capacitor, a fourth capacitor and a fifth capacitor which are electrically connected in sequence are arranged in the porcelain body to form a series capacitor layer, a first inductor, a second inductor, a third inductor and a fourth inductor are arranged in the porcelain body to form an inductor layer, and the input end and the output end of the series capacitor layer are connected to an input pin and an output pin respectively. And the first inductor, the second inductor, the third inductor and the fourth inductor are connected to a sixth capacitor, a seventh capacitor, an eighth capacitor and a ninth capacitor which are externally connected with the bottom of the porcelain body through lower inner electrodes and are variable in capacitance. By adopting the variable capacitor, the frequency can be adjusted.

Description

Technical Field

[0001] The utility model relates to a 350-2000MHz high-pass filter, belonging to the technical field of high-pass filters. Background Art

[0002] A high-pass filter is a system that allows high frequencies to pass more easily while preventing low frequencies from passing through. It filters out unnecessary low-frequency components in the signal or filters out low-frequency interference.

[0003] The existing LTCC high-pass filter is a filter with a fixed cutoff frequency. All components are integrated inside the ceramic body and the frequency is not variable. Summary of the Invention

[0004] The technical problem to be solved by the utility model is to provide a 350-2000MHz high-pass filter which can meet the requirement of variable frequency.

[0005] The technical solution adopted by the utility model is: a 350-2000MHz high-pass filter, comprising a 350-690MHz filter, a 690-1250MHz filter and a 1250-2000MHz filter connected in parallel, the two sections of which are connected in parallel and connected to a conversion switch, the 350-690MHz filter, the 690-1250MHz filter and the 1250-2000MHz filter all comprising an LTCC porcelain body, a first inductor, a second inductor, a third inductor, a fourth inductor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor and a fifth capacitor, wherein the first capacitor, the second capacitor, the third capacitor, the fourth capacitor and the fifth capacitor are arranged in the porcelain body and are electrically connected in sequence. The fourth capacitor and the fifth capacitor form a series capacitor layer. The first inductor, the second inductor, the third inductor, and the fourth inductor are three-dimensional inductors, which are arranged in the porcelain body to form an inductor layer. The formed inductor layer is located below the series capacitor layer. The input and output ends of the series capacitor layer are respectively connected to the input pins and output pins arranged on the series capacitor layer and the bottom of the porcelain body through the upper inner electrode and the side inner electrode. The first inductor, the second inductor, the third inductor, and the fourth inductor are all connected to the five external capacitor connection terminals at the bottom of the porcelain body through the lower inner electrode. The five external capacitor connection terminals are respectively connected to the sixth capacitor, the seventh capacitor, the eighth capacitor, and the ninth capacitor. The sixth capacitor, the seventh capacitor, the eighth capacitor, and the ninth capacitor are variable capacitors.

[0006] Furthermore, the distance between the capacitor layer and the inductor layer is 10-40 um.

[0007] The beneficial effects of the present invention are as follows: compared with the prior art, the present invention can achieve the requirement of variable frequency high-pass filter by adjusting the variable capacitor through external connection, thereby achieving the requirement of variable frequency band of 350-2000 MHz high-pass filter prepared by LTCC, and effectively solving the problem of fixed frequency of existing LTCC high-pass filter; through simulation verification, the three frequency bands of filters are all controlled by changing the variable capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a schematic diagram of the 350-690MHz filter's three-dimensional perspective structure;

[0009] Figure 2 This is a schematic diagram of the three-dimensional structure of the internal components of the 350-690MHz filter;

[0010] Figure 3 This is a three-dimensional structural diagram of the internal device layout of the 350-690MHz filter from another perspective;

[0011] Figure 4 This is a front-view structural diagram of the 350-690MHz filter's internal components connected to the external capacitor arrangement;

[0012] Figure 5 This is a left-view structural diagram of the internal device arrangement of the 350-690MHz filter;

[0013] Figure 6 This is a top view of the internal device layout of the 350-690MHz filter;

[0014] Figure 7 This is the simulation circuit diagram of the 350-690MHz filter;

[0015] Figure 8 This is the simulation waveform of the 350-690MHz filter. In the figure, (a) is 3PF and (b) is 30PF;

[0016] Figure 9 This is a schematic diagram of the 690-1250MHz filter's three-dimensional perspective structure;

[0017] Figure 10 This is the simulation waveform of the 690-1250MHz filter. In the figure, (a) is 2.5PF and (b) is 30PF;

[0018] Figure 11 This is a schematic diagram of the 1250-2000MHz filter's three-dimensional perspective structure;

[0019] Figure 12This is the simulation waveform of the 1250-2000MHz filter. In the figure, (a) is 2PF and (b) is 30PF. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1: Figure 1-12 As shown, a 350-2000MHz high-pass filter includes a 350-690MHz filter, a 690-1250MHz filter, and a 1250-2000MHz filter connected in parallel. The two sections of the parallel connection are connected to a transfer switch. The 350-690MHz filter, the 690-1250MHz filter, and the 1250-2000MHz filter each include an LTCC ceramic body 1, a first inductor 2, a second inductor 3, a third inductor 4, a fourth inductor 5, a first capacitor 6, a second capacitor 7, a third capacitor 8, a fourth capacitor 9, and a fifth capacitor 10. The first capacitor 6, the second capacitor 7, the third capacitor 8, the fourth capacitor 9, and the fifth capacitor 10 are arranged in the ceramic body 1 and are electrically connected in sequence to form a series capacitor layer. The first inductor 2, the second inductor 3, the third inductor 4, and the fourth inductor 5 are three-dimensional inductors, which are arranged in the ceramic body 1 to form an inductor layer. The inductor layer is located below the series capacitor layer. The input and output ends of the series capacitor layer are connected to the series capacitor layer and the input pin 11 and output pin 12 arranged at the bottom of the ceramic body 1 respectively through the upper inner electrode 18 and the side inner electrode 19. The first inductor 2, the second inductor 3, the third inductor 4, and the fourth inductor 5 are all connected to the five external capacitor connection terminals 13 at the bottom of the ceramic body 1 through the lower inner electrode 20. The five external capacitor connection terminals 13 are respectively connected to the sixth capacitor 14, the seventh capacitor 15, the eighth capacitor 16, and the ninth capacitor 17. The sixth capacitor 14, the seventh capacitor 15, the eighth capacitor 16, and the ninth capacitor 17 are variable capacitors. In order to achieve adjustable cutoff frequency, the grounding capacitor is designed to be external and replaced with a variable capacitor to achieve variable capacitance, thereby achieving variable frequency.

[0022] In order to meet the requirements and avoid mutual interference, the distance between the capacitor layer and the inductor layer is 10-40um.

[0023] The first frequency of the utility model covers 350-690MHz, and the frequency is adjustable by connecting an external variable capacitor. When the capacitance value is 3PF, the cut-off frequency is 690MHz. Figure 8 (a) shows the waveform when the capacitance value is 30PF and the cutoff frequency is 350MHz. Figure 8 As shown in (b), the filter frequency coverage of 350-690MHz is achieved by changing the capacitance from 3 to 30PF.

[0024] The second frequency range of the present invention is 650-1250MHz. The waveform when the capacitance value is 2.5PF and the cut-off frequency is 1250MHz is shown in Figure 10 (a). The waveform when the capacitance value is 30PF and the cut-off frequency is 650MHz is shown in Figure 10 (b). Figure 10 As shown in (b), the filter frequency coverage of 650-1250MHz is achieved by changing the capacitance from 2.5 to 30PF.

[0025] The third frequency of the present invention covers 1220-2000MHz, the waveform when the capacitance value is 2PF, and the cut-off frequency is 2000MHz. Figure 12 (a) shows the waveform when the capacitance value is 30PF and the cutoff frequency is 1220MHz. Figure 12 As shown in (b), the filter frequency coverage of 1220-2000MHz is achieved by changing the capacitance from 2 to 30PF.

[0026] The three filters are connected in parallel, and the high-pass filter cutoff frequency can be changed from 350-2000MHz by switching.

[0027] Example 2: A method for preparing a 350-2000 MHz high-pass filter. After preparing a 350-690 MHz filter, a 690-1250 MHz filter, and a 1250-2000 MHz filter, a switch is connected to switch the frequency band. The methods for preparing the 350-690 MHz filter, the 690-1250 MHz filter, and the 1250-2000 MHz filter all use the following steps:

[0028] S1. Ingredients: Select a material with a dielectric constant of 5.1 and ball-mill the powder to a particle size of 0.3-0.5 μm;

[0029] S2, tape casting: the milled ingredients are prepared into slurry, and the tape casting technology is used to obtain green porcelain tapes of different thicknesses;

[0030] S3, cutting: cutting the raw porcelain strip into 6-inch raw porcelain strips of various thicknesses;

[0031] S4. Drilling: according to the prepared drilling pattern, use a laser drilling machine to drill holes on the raw porcelain strip where holes need to be drilled;

[0032] S5. Printing: The printing method is screen printing. The filter design pattern of the corresponding frequency band of the high-pass filter is prepared on the film. After exposure, the inductor of the filter and the capacitor installed inside the porcelain body are transferred to a 500-mesh steel screen covered with photosensitive adhesive (higher precision printing lines). The capacitor uses a 400-mesh steel screen to form a printing jig. The thickness of the photosensitive adhesive coating is controlled to be 42μm-55μm; the printing GAP value is 1mm-3mm; the pressure of the printing scraper is 0.05MPa-0.10MPa; the scraper step speed is 0.01m / s-0.05m / s; each layer of the design model containing the inductor or capacitor pattern is printed on the green porcelain tape of the corresponding thickness. The printed inductor line width error is within 1μm, the inductor thickness is 12-15μm, the printed capacitor length and width error is within 5μm, and the capacitor thickness is 8-10μm.

[0033] S6. Lamination: Use a fully automatic alignment lamination machine to laminate the printed raw ceramic tapes according to the design sequence;

[0034] S7, Isostatic Pressing: Final pressing is performed on the laminated membrane using isostatic pressing. Maximum isostatic pressing temperature: 85±5°C; holding time: 900s; holding pressure: 5100±100psi to form a Bar block.

[0035] S8, cutting: split the bar block into independent product units of 6.95mm*4.63mm with an error of ±0.02mm;

[0036] S9, debinding: Debinding the split products for 36 hours according to the staged temperature debinding curve with a dielectric constant of 5.1. The staged temperatures of the debinding curve are as follows: gradually increase the temperature from RT to 270℃ for 15 hours; keep constant at 270℃ for 2 hours; gradually increase the temperature from 270℃ to 320℃ for 4 hours; keep constant at 320℃ for 2 hours; gradually increase the temperature from RT to 270℃ for 5 hours; gradually increase the temperature from 320℃ to 465℃ for 4 hours; keep constant at 465℃ for 5 hours; gradually cool down from 465℃ to RT;

[0037] S10, sintering: the debinding product is sintered in a tunnel furnace; the tunnel furnace belt speed is 45mm / min, there are 12 sintering temperature zones, the sintering temperature is 875℃, and the sintering time is 1h.

[0038] S11, chamfering: chamfering the sintered product;

[0039] S12, Silver Dipping: Use the fully automatic terminal electrode silver dipping machine to coat the external terminal electrodes of the chamfered products;

[0040] S13, Silver Burning: Silver burning process is performed on the silver-coated product; silver burning is performed using a tunnel furnace; there are 6 sintering temperature zones, sintering temperature: 715℃, holding time: 20min-25min;

[0041] S14, electroplating: After silver firing, the product is electroplated with nickel, tin and lead to obtain the final product.

[0042] The above is only a specific implementation method of the present invention, but the scope of protection of the present invention is not limited to this. Any technician familiar with the technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A 350-2000MHz high-pass filter, characterized in that: The invention comprises a 350-690MHz filter, a 690-1250MHz filter and a 1250-2000MHz filter connected in parallel, wherein the two sections are connected to a switching switch, wherein the 350-690MHz filter, the 690-1250MHz filter and the 1250-2000MHz filter each comprise a porcelain body (1), a first inductor (2), a second inductor (3), a third inductor (4), a fourth inductor (5), a first capacitor (6), a second capacitor (7), a third capacitor (8), a fourth capacitor (9) and a fifth capacitor (10), wherein the porcelain body (1) is provided with a first capacitor (6), a second capacitor (7), a third capacitor (8), a fourth capacitor (9) and a fifth capacitor (10) which are electrically connected in sequence to form a series capacitor layer, wherein the first inductor (2), the second inductor (3), the third inductor (4), The fourth inductor (5) adopts a three-dimensional inductor and is arranged in the porcelain body (1) to form an inductor layer. The formed inductor layer is located below the series capacitor layer. The input and output ends of the series capacitor layer are connected to the input pin (11) and the output pin (12) arranged at the bottom of the series capacitor layer and the porcelain body (1) through the upper inner electrode (18) and the side inner electrode (19). The first inductor (2), the second inductor (3), the third inductor (4), and the fourth inductor (5) are all connected to the five external capacitor connection terminals (13) at the bottom of the porcelain body (1) through the lower inner electrode (20). The five external capacitor connection terminals (13) are respectively connected to the sixth capacitor (14), the seventh capacitor (15), the eighth capacitor (16), and the ninth capacitor (17). The sixth capacitor (14), the seventh capacitor (15), the eighth capacitor (16), and the ninth capacitor (17) adopt variable capacitors.

2. A 350-2000 MHz high-pass filter according to claim 1, characterized in that: The distance between the capacitor layer and the inductor layer is 10-40um.

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