CN112332050A

CN112332050A - Correctable band-pass filter based on LTCC process

Info

Publication number: CN112332050A
Application number: CN202010729266.5A
Authority: CN
Inventors: 邢孟江; 易康; 代传相; 刘永红
Original assignee: Ningbo Haixiufeng Technology Co ltd
Current assignee: Ningbo Haixiufeng Technology Co ltd
Priority date: 2020-07-27
Filing date: 2020-07-27
Publication date: 2021-02-05

Abstract

The invention relates to a correctable band-pass filter based on an LTCC process, and belongs to the technical field of filters. The invention comprises an LTCC ceramic medium, wherein a resonator is formed in the LTCC ceramic medium, a metal layer is printed on the surface of the LTCC ceramic medium to form an input port, an output port, a correction module and a semi-closed metal cavity respectively, the input port is connected with an input feeder, the output port is connected with an output feeder, and the input feeder and the output feeder feed the resonator through narrow-edge coupling.

Description

Correctable band-pass filter based on LTCC process

Technical Field

The invention relates to a correctable band-pass filter based on an LTCC process, and belongs to the technical field of filters.

Background

Microwave band-pass filters have been widely used in wireless communication systems due to their advantages of flexibility, low return loss, high selectivity, and small size. The band-pass filter is widely applied to frequency selection and can be used in various occasions. In recent years, a miniaturized bandpass filter having excellent performance and small size has been a focus of research.

One of the bandpass filters based on LTCC technology is the bandpass filter, which has wide application in satellite communication systems and wireless communication systems. In the past, the design of LTCC-based bandpass filters is ideally performed in electromagnetic simulation software, but there are some inevitable factors in practical applications such as: the dielectric constant of 1 dielectric material will change with temperature change. 2, when in processing, the resonator, the input and output feeder lines, the semi-closed metal cavity, the input and output ports and the ceramic medium have slight errors due to process precision. These factors all cause the performance of the filter to deviate from the design, and finding a general method for correcting the deviation has great practical value.

Disclosure of Invention

The invention aims to overcome the defects of the existing filter and provides a correctable band-pass filter based on an LTCC process.

The invention is realized by adopting the following technical scheme:

the utility model provides a can revise band-pass filter based on LTCC technology, includes LTCC ceramic medium, is formed with the resonator in the LTCC ceramic medium, the surface printing of LTCC ceramic medium has the metal level, forms input port, output port, correction module and semi-enclosed metal cavity respectively, and input port is connected with the input feeder, and the output port is connected with the output feeder, and input feeder and output feeder feed the resonator.

Furthermore, the resonators are of metal strip line structures, one end of each resonator is connected with the semi-closed metal cavity, the other end of each resonator is connected with the correction module, and the number of the resonators is N, wherein N is larger than or equal to 3.

Further, the input port and the output port are two folding surfaces with 90-degree folding angles.

Furthermore, the semi-closed metal cavity is a full opening on the side where the correction module is located, and the metal folding surfaces of the input port and the output port are local openings on the periphery.

Furthermore, the correction modules are rectangular metal layers, the thickness of each metal layer is the same as that of the semi-closed metal cavity, and the number of the correction modules is the same as that of the resonators and the correction modules are connected one by one.

Further, the distances between adjacent correction modules are the same.

Further, if N is an odd number, the shape of the middle correcting module is a rectangle with openings at two ends, and the rest correcting modules are complete rectangles; if N is an even number, the middle two correction modules are rectangular with openings at two ends, and the rest correction modules are complete rectangles.

Further, the operation of the correction module is to print the metal layer preliminarily and then to perform the fine correction by laser according to the test performance index of the filter.

Further, the single refinement step of the correction module is a 50um by 50um square.

Furthermore, the input feeder and the first resonator feed in a narrow-side coupling mode, and the output feeder and the Nth resonator feed in a narrow-side coupling mode.

The invention has the beneficial effects that:

the invention adopts the LTCC lamination co-firing process, integrates the resonators in the medium, and adjusts the bandwidth and the center frequency of the filter by adjusting the size of the resonators and the distance between the adjacent resonators; the input feeder line and the output feeder line carry out feeding in a narrow-edge coupling mode, and the out-of-band characteristic of the filter is adjusted through the coupling distance; and introducing a correction module, primarily printing a metal layer on the surface of the LTCC ceramic medium, and finely correcting by laser according to the test performance index of the filter, thereby correcting the performance parameter of the band-pass filter, and finally realizing the advantages of small size, small in-band insertion loss and capability of correcting the performance parameter of the filter.

Drawings

FIG. 1 is a schematic view of the overall structure of the present invention;

FIG. 2 is a schematic view of the internal structure of the present invention;

FIG. 3 is a schematic view of an external package structure according to the present invention;

FIG. 4 is a schematic structural diagram of a correction module according to the present invention;

FIG. 5 is the S parameter simulation result of the present invention

The labels in the figure are: 1. an LTCC ceramic dielectric; 2. a resonator; 201. a first resonator; 202. a second resonator; 203. a third resonator; 3. inputting a feeder line; 4. outputting a feeder line; 5. a semi-enclosed metal cavity; 6. an input port; 7. an output port; 8. a correction module; 801. a first correction module; 802. a second correction module; 803. and a third correction module.

Detailed Description

The invention will be further explained with reference to the drawings.

As shown in fig. 1, the correctable bandpass filter of the present embodiment includes an LTCC ceramic dielectric 1, a resonator 2, an input feed line 3, an output feed line 4, a semi-enclosed metal cavity 5, an input port 6, an output port 7 and a correction module 8; the input port 6, the output port 7, the correction module 8 and the semi-closed metal cavity 5 are metal layers covering the surface of the LTCC ceramic medium 1, the thickness is 15um, the thicknesses of the input feeder line 3, the output feeder line 4 and the resonator 2 are all 10um and are all located in a middle medium layer of the LTCC ceramic medium 1, the input port 6 is connected with the input feeder line 3, the output port 7 is connected with the output feeder line 4, the semi-closed metal cavity 5 is fully opened on the side face where the correction module 8 is located, the peripheries of the input port 6 and the output port 7 are partially opened, namely, the area of the opening is larger than the area of the port, short circuit is prevented when the semi-closed metal cavity is used, and particularly, the distance between the. The resonator 2 penetrates through the whole LTCC ceramic dielectric 1, one end of the resonator is connected with the semi-closed metal cavity 5, the other end of the resonator is connected with the correction module 8, and the size of the LTCC ceramic dielectric 1 is 4mm 9.6mm 9.2 mm.

As shown in fig. 2, the internal structure of the correctable bandpass filter of this embodiment is schematically illustrated, the bandpass filter includes 3 resonators 2 having a same stripline structure, the width of the resonators 2 is 0.4mm to 0.6mm, the distance between adjacent resonators 2 is 2.2mm to 2.4mm, the input feed line 3 and the output feed line 4 are symmetrically distributed, and are irregular metal blocks, and the specific dimensions are as follows: the length is 2.8mm-2.9mm, the maximum width is 0.5mm larger than the second width, wherein, the input feeder 3 is coupled and fed with the first resonator 201 through the narrow side, the first resonator 201 and the second resonator 202 are coupled to form a passage, the second resonator 202 and the third resonator 203 are coupled to form a passage, the output feeder 4 is coupled and fed with the third resonator 203 through the narrow side, and the coupling distance is 0.1 mm.

As shown in fig. 3, the external structure of the correctable bandpass filter of this embodiment is schematically illustrated, the external structure includes an input port 6, an output port 7, a correcting module 8 and a semi-enclosed metal cavity 5, and the external structure is a metal layer covered on the surface of the LTCC ceramic dielectric 1 and has a thickness of 15 um. The input port 6 and the output port 7 are two metal folding surfaces with folding angles of 90 degrees on the LTCC ceramic medium 1, the input port 6 and the output port 7 have symmetry, and the correction module 8, the input port 6 and the output port 7 are not intersected with the semi-closed metal cavity 5.

As shown in fig. 4, a schematic diagram of a correction module of the correctable bandpass filter of this embodiment is shown, where the number of the correction modules 8 is the same as that of the resonators 2, the first resonator 201 is connected to the first correction module 801, the second resonator 202 is connected to the second correction module 802, the third resonator 203 is connected to the third correction module 803, the first correction module 801 and the third correction module 803 are rectangular metal blocks with the same shape, the second correction module 802 is rectangular with openings at both ends, gaps between the first correction module 801 and the second correction module 802 and between the third correction module 803 and the second correction module 802 are equal to 0.25mm, if N is an odd number, the shape of the middle correction module is rectangular with openings at both ends, and the remaining correction modules are complete rectangles; if N is an even number, the two middle correction modules are rectangular with openings at two ends, the other correction modules are complete rectangles, and the openings at two ends of the correction modules are used as positioning centers of the correction modules.

As shown in fig. 5: the center frequency of the band-pass filter of the embodiment is 1.232GHz, the passband bandwidth is 1.164GHz to 1.300GHZ, the insertion loss in the passband is less than 1.001dB, and the return loss is more than 15 dB; in the resistance band, the inhibition is more than 35dB in the range of DC-0.964 GHz, and the inhibition is more than 15dB in the range of 1.5-1.75 GHz.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. The utility model provides a can revise band-pass filter based on LTCC technology, its characterized in that includes LTCC ceramic medium (1), be formed with resonator (2) in LTCC ceramic medium (1), the surface printing of LTCC ceramic medium (1) has the metal level, forms input port (6), output port (7), modification module (8) and semi-enclosed metal cavity (5) respectively, and input port (6) are connected with input feeder (3), output port (7) are connected with output feeder (4), and input feeder (3) and output feeder (4) feed resonator (2).

2. The LTCC process based modifiable bandpass filter according to claim 1, wherein: the resonator (2) is of a metal strip line structure, one end of the resonator is connected with the semi-closed metal cavity (5), the other end of the resonator is connected with the correction module (8), the number of the resonators (2) is N, and N is larger than or equal to 3.

3. The LTCC process based modifiable bandpass filter according to claim 1, wherein: the input port (6) and the output port (7) are two folding surfaces with 90-degree folding angles.

4. The LTCC process based modifiable bandpass filter according to claim 1, wherein: the semi-closed metal cavity (5) is fully opened on the side where the correction module (8) is located, and is partially opened on the periphery of the metal folding surfaces of the input port (6) and the output port (7).

5. The LTCC process based modifiable bandpass filter according to claim 1, wherein: the correction modules (8) are rectangular metal layers, the thickness of each metal layer is the same as that of the semi-closed metal cavity (5), and the number of the correction modules (8) is the same as that of the resonators (2) and the correction modules are connected one by one.

6. The LTCC process based modifiable bandpass filter according to claim 5, wherein: the distances between adjacent correction modules (8) are the same.

7. The LTCC process based modifiable bandpass filter according to claim 5, wherein: if N is an odd number, the shape of the middle correcting module (8) is a rectangle with openings at two ends, and the other correcting modules (8) are complete rectangles; if N is an even number, the middle two correction modules (8) are rectangular with openings at two ends, and the other correction modules (8) are complete rectangles.

8. The LTCC process based modifiable bandpass filter according to claim 5, wherein: the operation of the correction module (8) is to print the metal layer preliminarily and then carry out the fine correction by laser according to the test performance index of the filter.

9. The LTCC process based modifiable bandpass filter according to claim 8, wherein: the single finishing step of the correction module (8) is a square block of 50um by 50 um.

10. The LTCC process based modifiable bandpass filter according to claim 2, wherein: the input feeder (3) and the first resonator (201) feed in a narrow-side coupling mode, and the output feeder (4) and the Nth resonator feed in a narrow-side coupling mode.