CN110048202B - LTCC band-pass filter loaded with square ridges and shielding layer - Google Patents
LTCC band-pass filter loaded with square ridges and shielding layer Download PDFInfo
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- CN110048202B CN110048202B CN201910285856.0A CN201910285856A CN110048202B CN 110048202 B CN110048202 B CN 110048202B CN 201910285856 A CN201910285856 A CN 201910285856A CN 110048202 B CN110048202 B CN 110048202B
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- H01P1/20—Frequency-selective devices, e.g. filters
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Abstract
The invention discloses an LTCC band-pass filter loaded with square ridges and a shielding layer. The filter comprises a shielding layer, a metal column and a dielectric layer which are arranged from top to bottom, wherein the metal column is used for supporting the shielding layer above the dielectric layer, the upper end of the metal column is connected with the shielding layer, and the lower end of the metal column is connected with the dielectric layer; the upper surface and the lower surface of the dielectric layer are respectively provided with a first metal patch and a second metal patch, one side of the first metal patch is connected with the input end through a first microstrip line, and the other side of the first metal patch is connected with the output end through a second microstrip line; the four side lines of the first metal patch and the second metal patch are provided with metal through holes, the first metal patch, the second metal patch and the metal through holes form 3 resonant cavities in the first medium layer, a square ridge is embedded between the first microstrip line and the second microstrip line and the adjacent resonant cavities respectively, and the square ridge is located at the maximum position of an electric field. The filter has the advantages of small volume and light weight, improves the out-of-band rejection performance and reduces the return loss in a pass band.
Description
Technical Field
The invention relates to the technical field of microwave filters, in particular to an LTCC band-pass filter loaded with square ridges and a shielding layer.
Background
With the development of microwave and millimeter wave integrated circuit technology, various electronic devices are developed in a direction of small size and higher reliability in order to realize multi-functional mixing of systems. Low temperature co-fired ceramic (LTCC) technology has become the mainstream technology of passive integration by virtue of the advantages of high integration, high heat resistance, high quality factor, etc.
Compared with the traditional rectangular waveguide filter, the Substrate Integrated Waveguide (SIW) filter has the advantages of richer implementation forms, more flexible structure, easiness in processing, easiness in combination with other circuit components and parts, and suitability for integration and manufacturing of microwave and millimeter wave circuits. Since the SIW filter is mostly a planar structure, the structure size is relatively large at low frequencies.
In order to reduce the size of the device, LTCC technology is combined with SIW technology to both reduce the size and to perform the function of the integrated waveguide on the entire substrate. However, the conventional substrate integrated waveguide band-pass filter has the defect that the out-of-band rejection and the in-pass return loss cannot be balanced, and is not easy to control and adjust.
Disclosure of Invention
The invention aims to provide an LTCC band-pass filter loaded with square ridges and a shielding layer, which has high out-of-band inhibition performance and low return loss in a pass band.
The technical solution for realizing the purpose of the invention is as follows: the utility model provides a LTCC band pass filter of square spine of loading and shielding layer, includes shielding layer, metal column and the dielectric layer that from top to bottom sets up, wherein:
the metal column is used for supporting the shielding layer above the dielectric layer, the upper end of the metal column is connected with the shielding layer, and the lower end of the metal column is connected with the dielectric layer;
the upper surface and the lower surface of the dielectric layer are respectively provided with a first metal patch and a second metal patch, one side of the first metal patch is connected with the input end through a first microstrip line, and the other side of the first metal patch is connected with the output end through a second microstrip line;
the four side edges of the first metal patch and the second metal patch are provided with metal through holes, the first metal patch, the second metal patch and the metal through holes form 3 resonant cavities in the dielectric layer, a square ridge is embedded between the first microstrip line and the second microstrip line and the adjacent resonant cavities respectively, and the square ridge is located at the position where the electric field is maximum.
Furthermore, the 3 resonant cavities are sequentially a first resonant cavity, a second resonant cavity and a third resonant cavity from input to output along the horizontal direction, the 3 resonant cavities are longitudinally separated by 4 rows of mutually parallel through holes, and the number of the through holes in each row is 4 and is symmetrical up and down.
Furthermore, a first square ridge is embedded between the first microstrip line and the first resonant cavity, a second square ridge is embedded between the second microstrip line and the output end, and the first square ridge and the second square ridge penetrate into the dielectric layer and are coplanar with the first metal patch.
Furthermore, each metal through hole sequentially penetrates through the first metal patch, the dielectric layer and the second metal patch from top to bottom.
Furthermore, the number of the metal columns is 4, and the metal columns are arranged at 4 corners of the dielectric layer.
Further, the shielding layer is parallel to the first metal patch.
Furthermore, the first square ridge is arranged between the first microstrip line and the first resonant cavity, and the first square ridge extends into the dielectric layer and is coplanar with the first metal patch; the second square ridge is arranged between the second microstrip line and the third resonant cavity, penetrates into the dielectric layer and is coplanar with the first metal patch; the first square ridge and the second square ridge are both close to the metal through hole.
Further, the thickness of the dielectric layer is 0.127mm, the dielectric constant is 7.1, and the overall thickness of the filter is 1.127 mm.
Compared with the prior art, the invention has the following remarkable advantages: (1) the insertion loss and the return loss of the filter are reduced by adopting a shielding layer structure; (2) the square ridge is combined with the LTCC band-pass filter, the rotation angle of the square ridge and the depth of the embedded dielectric layer are adjusted, so that the selectivity, the out-of-band rejection and other performances of the filter are conveniently adjusted, the high selectivity can be realized while the narrow-band-pass filtering characteristic is realized, and the out-of-band rejection performance and the difference loss are improved; (3) the LTCC band-pass filter is designed by adopting the technology of loading square ridges and shielding layers, and has the advantages of simple structure, small volume, light weight and easy realization.
Drawings
Fig. 1 is a schematic structural diagram of an LTCC bandpass filter loaded with square ridges and a shielding layer according to the present invention, wherein (a) is a side view and (b) and (c) are top surface circuit diagrams of dielectric layers.
Fig. 2 is a graph comparing the S-parameters of LTCC bandpass filters loaded with square ridges and shielding layers according to an embodiment of the present invention.
Detailed Description
The present invention is described in further detail below with reference to the attached drawing figures.
With reference to fig. 1(a) - (c), the LTCC bandpass filter loaded with the square ridge and the shielding layer of the present invention includes a shielding layer 1, a metal pillar 2 and a dielectric layer 3 arranged from top to bottom, wherein:
the metal column 2 is used for supporting the shielding layer 1 above the dielectric layer 3, the upper end of the metal column 2 is connected with the shielding layer 1, and the lower end of the metal column 2 is connected with the dielectric layer 3;
the upper surface and the lower surface of the dielectric layer 3 are respectively provided with a first metal patch 31 and a second metal patch 32, one side of the first metal patch 31 is connected with the input end 4 through a first microstrip line 41, and the other side is connected with the output end 5 through a second microstrip line 51;
the four side edges of the first metal patch 31 and the second metal patch 32 are respectively provided with a metal through hole 6, the first metal patch 31, the second metal patch 32 and the metal through holes 6 form 3 resonant cavities in the dielectric layer 3, a square ridge is respectively embedded between the first microstrip line 41 and the second microstrip line 51 and the adjacent resonant cavities, and the square ridge is positioned at the maximum electric field.
As a specific example, the 3 resonant cavities are a first resonant cavity 71, a second resonant cavity 72 and a third resonant cavity 73 in sequence from input to output along the horizontal direction, the longitudinal directions of the 3 resonant cavities are separated by 4 columns of mutually parallel through holes 9, and the number of each column of through holes 9 is 4 and is symmetrical up and down.
As a specific example, a first square ridge 81 is embedded between the first microstrip line 41 and the first resonant cavity 71, a second square ridge 82 is embedded between the second microstrip line 51 and the output end 5, and the first square ridge 81 and the second square ridge 82 penetrate into the dielectric layer 3 and are coplanar with the first metal patch 31.
As a specific example, each metal via 6 sequentially penetrates through the first metal patch 31, the dielectric layer 3, and the second metal patch 32 from top to bottom.
As a specific example, the number of the metal posts 2 is 4, and the metal posts are arranged at 4 corners of the dielectric layer 3.
As a specific example, the shielding layer 1 is parallel to the first metal patch 31. The first metal patch 31 and the second metal patch 32 are not consistent in structure, the first metal patch 31 has a microstrip line structure, and the second metal patch 32 does not have a microstrip line structure.
As a specific example, the first square ridge 81 is disposed between the first microstrip line 41 and the first resonant cavity 71, and the first square ridge 81 extends into the dielectric layer 3 and is coplanar with the first metal patch 31; the second square ridge 82 is arranged between the second microstrip line 51 and the third resonant cavity 73, and the second square ridge 82 extends into the dielectric layer 3 and is coplanar with the first metal patch 31; the first square ridge 81 and the second square ridge 82 are both close to the metal via 6.
As a specific example, the thickness of the dielectric layer 3 is 0.127mm, the dielectric constant is 7.1, and the overall thickness 13 of the filter is 1.127 mm.
The invention discloses an LTCC band-pass filter loaded with square ridges and a shielding layer, which comprises the following parameter design processes:
the thickness of the dielectric layer 3 is 0.127mm, the whole thickness of the filter is 1.127mm, and the dielectric constant of the dielectric is 7.1.
Optimizing the first square ridge 81 and the second square ridge 82, and adjusting the depths 811 and 821 of the square ridges embedded in the dielectric layer to ensure that the cut-off frequency of the designed LTCC band-pass filter with the substrate loaded with the square ridges has high selectivity;
(III) according to the cut-off frequency fcThe widths of the first metal patch 31 and the second metal patch 32 in the substrate integrated waveguide band-pass filter are determined, namely the vertical distance from the axis connecting line of the metal through hole 6 to the opposite side line is determined according to the following formula:
in the formula (f)cThe cut-off frequency of the LTCC band-pass filter loaded with the square ridges and the shielding layer is v, the propagation speed of light in the dielectric layer 3 is lambdacIs a cut-off frequency fcCorresponding wavelength, aequIs the equivalent width of a rectangular patch, asiwThe actual width of the rectangular patch, c the speed at which light travels in a vacuum,rin the dielectric constant of the dielectric layer 7.1, d is the diameter of the metal via 6 (d 2 is the diameter of the via 6 in fig. 1 (b)), and p is the distance between the centers of the adjacent metal vias 6 (p 9 is the distance between the centers of the adjacent metal vias 6 in fig. 1 (b)).
And fourthly, optimizing the sizes 811 and 821 of the first square ridge 81 and the second square ridge 82, the position of the metal through hole 6, the first microstrip line 41 and the second microstrip line 51 respectively, and finally optimizing and debugging the whole filter to ensure that the performance requirement of the filter meets the design index.
Example 1
In conjunction with FIGS. 1(a) - (c), this embodiment designs a cut-off frequency fcThe LTCC band-pass filter is a 99GHz LTCC band-pass filter loaded with square ridges and a shielding layer, the in-band return loss is less than-15 dB, and the out-of-band insertion loss is less than-36 dB.
The LTCC band-pass filter loaded with the square ridges and the shielding layers comprises the shielding layers 1, metal pillars 2 and dielectric layers 3 which are arranged from top to bottom, wherein 4 metal pillars 2 are arranged, the upper ends of the metal pillars are connected with the shielding layers 1, and the lower ends of the metal pillars are connected with the dielectric layers 3; the upper surface of the dielectric layer 3 is provided with a first metal patch 31, an input end 4, a first microstrip line 41, a second microstrip line 51, an output end 5, a first square ridge 81 and a second square ridge 82, and the lower surface of the dielectric layer 3 is provided with a second metal patch 32 at a position corresponding to the first metal patch 31;
one side of the first metal patch 31 is connected with one side of the first microstrip line 41, and the other side of the first microstrip line 41 is connected with the input end 4; the other side of the first metal patch 31 is connected with one side of a second microstrip line 51, and the other side of the second microstrip line 51 is connected with an output end 5;
the four side lines of the first metal patch 31 and the second metal patch 32 are provided with metal through holes 6, and each metal through hole 6 sequentially penetrates through the first metal patch 31, the dielectric layer 3 and the second metal patch 32 from top to bottom;
the first metal patch 31, the second metal patch 32 and the metal through hole 6 form a first resonant cavity 71, a second resonant cavity 72 and a third resonant cavity 73 in the dielectric layer 3, wherein the first resonant cavity 71 is close to the input end 4, and the third resonant cavity 73 is close to the output end 5;
a first square ridge 81 is embedded between the first microstrip line 41 and the first resonant cavity 71, a second square ridge 82 is embedded between the second microstrip line 51 and the output end 5, and the first square ridge 81 and the second square ridge 82 penetrate into the dielectric layer 3 and are coplanar with the first metal patch 31; the first square ridge 81 and the second square ridge 82 are both located where the electric field is maximum.
Further, the shielding layer 1 is parallel to the first metal patch 31.
Further, the first square ridge 81 is disposed between the first microstrip line 41 and the first resonant cavity 71, and the first square ridge 81 extends into the dielectric layer 3 and is coplanar with the first metal patch 31; the second square ridge 82 is arranged between the second microstrip line 51 and the third resonant cavity 73, and the second square ridge 82 extends into the dielectric layer 3 and is coplanar with the first metal patch 31; the first square ridge 81 and the second square ridge 82 are both close to the metal via 6.
The material of the dielectric layer 3 is DGT9K7 with a dielectric constantrThe thickness of the dielectric layer 3 is 7.1 mm; the diameter d1 of the metal through hole 6 is 0.32mm, d2 is 0.34mm, d3 is 0.1mm, d4 is 0.14mm, the distance between the centers of adjacent metal through holes 6 is p9 is 0.6mm, p10 is 0.45mm, p11 is 1.89mm, p12 is 0.8mm, p13 is 0.41mm, p14 is 0.385mm, p15 is 0.21mm, and p16 is 0.31 mm; the lengths of the first microstrip line 41 and the second microstrip line 51 are 2.59 mm; the dimension 811 of the first square ridge 81 is 0.1038mm,812 is 0.5mm, and 813 is 0.04 mm; the dimension 821 of the second square ridge 82 is 0.1075mm,822 is 0.5mm,823 is 0.01 mm;
FIG. 2 is an S parameter diagram of the LTCC band-pass filter loaded with the square ridges and the shielding layer, the upper sideband of the LTCC band-pass filter loaded with the square ridges and the shielding layer is 99GHz, the cut-off frequency of the designed band-pass filter is obtained, no parasitic pass-band exists in a frequency band of 95-102 GHz, the band-pass characteristic is good from 95GHz to 102GHz, and the band-pass characteristic selection performance is good at the cut-off frequency.
In summary, the LTCC band-pass filter loaded with the square ridge and the shielding layer of the present invention adopts the method of loading the square ridge and the shielding layer, and utilizes the isolation characteristic of the shielding layer and the frequency selection characteristic of the square ridge, so as to effectively reduce the return loss and insertion loss of the filter, and enhance the out-of-band suppression effect of the filter, and the LTCC band-pass filter has a simple structure and is easy to implement.
Claims (6)
1. The utility model provides a LTCC band pass filter of loading square spine and shielding layer which characterized in that, is including shielding layer (1), metal column (2) and dielectric layer (3) that from top to bottom set up, wherein:
the metal column (2) is used for supporting the shielding layer (1) above the dielectric layer (3), the upper end of the metal column (2) is connected with the shielding layer (1), and the lower end of the metal column is connected with the dielectric layer (3);
the upper surface and the lower surface of the dielectric layer (3) are respectively provided with a first metal patch (31) and a second metal patch (32), one side of the first metal patch (31) is connected with the input end (4) through a first microstrip line (41), and the other side of the first metal patch is connected with the output end (5) through a second microstrip line (51);
the four side lines of the first metal patch (31) and the second metal patch (32) are respectively provided with a metal through hole (6), the first metal patch (31), the second metal patch (32) and the metal through holes (6) form 3 resonant cavities in the dielectric layer (3), a square ridge is respectively embedded between the first microstrip line (41), the second microstrip line (51) and the adjacent resonant cavities, and the square ridge is positioned at the maximum electric field;
the 3 resonant cavities are sequentially a first resonant cavity (71), a second resonant cavity (72) and a third resonant cavity (73) from input to output along the horizontal direction, the 3 resonant cavities are longitudinally separated by 4 rows of mutually parallel through holes (9), and the number of each row of through holes (9) is 4 and is symmetrical up and down;
a first square ridge (81) is embedded between the first microstrip line (41) and the first resonant cavity (71), a second square ridge (82) is embedded between the second microstrip line (51) and the output end (5), and the first square ridge (81) and the second square ridge (82) penetrate into the dielectric layer (3) and are coplanar with the first metal patch (31).
2. The LTCC band-pass filter loaded with square ridges and shielding layers according to claim 1, wherein each of said metal vias (6) penetrates through the first metal patch (31), the dielectric layer (3) and the second metal patch (32) from top to bottom in sequence.
3. The square ridge and shield loaded LTCC bandpass filter according to claim 1, wherein the number of the metal pillars (2) is 4, and the metal pillars are arranged at 4 corners of the dielectric layer (3).
4. The square ridge and shield loaded LTCC bandpass filter according to claim 1, wherein the shield (1) is parallel to the first metal patch (31).
5. The square ridge and shield loaded LTCC bandpass filter according to claim 1, wherein the first square ridge (81) is arranged between the first microstrip line (41) and the first resonant cavity (71), the first square ridge (81) is deep into the dielectric layer (3) and coplanar with the first metal patch (31); the second square ridge (82) is arranged between the second microstrip line (51) and the third resonant cavity (73), and the second square ridge (82) penetrates into the dielectric layer (3) and is coplanar with the first metal patch (31); the first square ridge (81) and the second square ridge (82) are close to the metal through hole (6).
6. The square ridge and shield loaded LTCC bandpass filter according to claim 1, wherein the dielectric layer (3) has a thickness of 0.127mm, a dielectric constant of 7.1 and an overall filter thickness (13) of 1.127 mm.
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| TW404091B (en) * | 1997-05-16 | 2000-09-01 | Murata Manufacturing Co | Ladder filter having edge-reflection type resonators |
| CN102709658B (en) * | 2012-06-08 | 2014-04-16 | 哈尔滨工业大学 | Half mode double-ridge substrate integrated waveguide with transitional balanced micro-strip lines |
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2019
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| US6535083B1 (en) * | 2000-09-05 | 2003-03-18 | Northrop Grumman Corporation | Embedded ridge waveguide filters |
| US7659799B2 (en) * | 2005-11-25 | 2010-02-09 | Electronics And Telecommunications Research Institute | Dielectric waveguide filter with cross-coupling |
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