Tsv-based dual-layer fourth-order cross-coupled siw filter

Abstract

The application discloses a kind of double-layer four-order cross-coupling SIW filters based on TSV, from top to bottom sequentially include: first metal layer, including input port and output port;First substrate layer, including a plurality of first through holes, a plurality of first through holes form first resonant cavity and second resonant cavity, both produce magnetic coupling through shared side wall window;Second metal layer, including first recess and second recess;Second substrate layer, including a plurality of second through holes, a plurality of second through holes form third resonant cavity and fourth resonant cavity, both produce magnetic coupling through shared side wall window, first recess is used to introduce electric coupling between first resonant cavity and third resonant cavity, second recess is used to introduce magnetic coupling between second resonant cavity and fourth resonant cavity;Third metal layer is located on the side of second substrate layer away from second metal layer.SIW filter can be realized using three-dimensional integrated circuit and silicon-based vertical via technology, become passive device miniaturization and integration good candidate.

Description

Technical Field

[0001] This invention belongs to the field of microwave filter technology, specifically relating to a two-layer fourth-order cross-coupled SIW filter based on TSV (Through Silicon Via). Background Technology

[0002] With the rapid development of wireless communication networks, the demand for high-frequency, high-bandwidth microwave communication is becoming increasingly strong. Microwave filters, as a crucial component in wireless communication networks, play a vital role in separating and filtering signals of different frequencies, and their performance significantly impacts the overall quality of the wireless communication system. In the radio frequency (RF) circuits of wireless communication systems, each filter plays a distinct and irreplaceable role. Depending on the system, filter specifications such as center frequency, bandwidth, out-of-band rejection, and size all have different requirements.

[0003] Currently, traditional Substrate Integrated Waveguide (SIW) filters are mainly manufactured based on Low Temperature Co-fired Ceramics (LTCC) technology. The process involves pressing low-temperature sintered ceramic powder into a uniform and dense ceramic strip. Then, drilling, slurry injection, and printing processes are performed on the ceramic strip to create the required circuit patterns. Finally, electronic components such as capacitors, resistors, and filters are embedded in a multi-layered ceramic substrate and stacked together. The entire system is then sintered at approximately 900°C to form a highly integrated, three-dimensional electronic circuit that does not interfere with each other. The main characteristics of SIW filters based on LTCC technology are small size, high precision, and high stability.

[0004] However, the aforementioned SIW filters also have some drawbacks, such as poor heat dissipation, center frequency shift due to the different thermal expansion coefficients of the ceramic substrate and the conductor metal, unsuitability for on-chip integration, and high insertion loss in the terahertz band. Therefore, filters made using LTCC technology cannot be suitable for high-frequency bands. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, this invention provides a two-layer fourth-order cross-coupled SIW filter based on TSV. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] This invention provides a TSV-based two-layer fourth-order cross-coupled SIW filter, comprising:

[0007] The first metal layer includes input ports and output ports;

[0008] A first substrate layer, located on one side of the first metal layer, includes a plurality of first vias, the plurality of first vias forming a first resonant cavity and a second resonant cavity, and the first resonant cavity and the second resonant cavity are magnetically coupled through a shared sidewall window;

[0009] The second metal layer is located on the side of the first substrate layer away from the first metal layer, and includes a first groove and a second groove.

[0010] The second substrate layer, located on the side of the second metal layer away from the first substrate layer, includes a plurality of second vias, the plurality of second vias forming a third resonant cavity and a fourth resonant cavity, and the third resonant cavity and the fourth resonant cavity are magnetically coupled through a shared sidewall window, the first groove is used to introduce electrical coupling between the first resonant cavity and the third resonant cavity, and the second groove is used to introduce magnetic coupling between the second resonant cavity and the fourth resonant cavity.

[0011] The third metal layer is located on the side of the second substrate layer away from the second metal layer.

[0012] In one embodiment of the present invention, the input port and the output port are both in the form of microstrip lines. In a first direction, the input port and the output port are respectively located on both sides of the first metal layer; the first direction is the direction from the first resonant cavity to the second resonant cavity.

[0013] In one embodiment of the present invention, the first resonant cavity includes a first coupling window, and the second resonant cavity includes a second coupling window. In a direction perpendicular to the plane where the first substrate layer is located, the orthographic projection of the input port overlaps with the orthographic projection of the first coupling window, and the orthographic projection of the output port overlaps with the orthographic projection of the second coupling window.

[0014] In one embodiment of the present invention, the first groove and the second groove are filled with silicon material.

[0015] In one embodiment of the present invention, in a direction perpendicular to the plane of the second metal layer, the orthographic projection of the first groove is a circle, and the orthographic projection of the center of the circle coincides with the orthographic projection of the center of the first resonant cavity.

[0016] In one embodiment of the present invention, the second groove includes a first sub-groove and a second sub-groove, and the second resonant cavity includes a first side and a second side disposed opposite to each other in a second direction;

[0017] In a direction perpendicular to the plane of the second metal layer, the orthographic projections of the first sub-groove and the second sub-groove are both rectangles, and the distance between the orthographic projection of the first sub-groove and the orthographic projection of the first side and the distance between the orthographic projection of the second sub-groove and the orthographic projection of the second side are equal; wherein, the second direction is perpendicular to the first direction, and both the first direction and the second direction are parallel to the plane of the second metal layer.

[0018] In one embodiment of the present invention, the first metal layer, the second metal layer and the third metal layer have the same thickness, which is 5 μm.

[0019] In one embodiment of the present invention, the materials of the first metal layer, the second metal layer and the third metal layer are copper.

[0020] In one embodiment of the present invention, the first substrate layer and the second substrate layer have the same thickness, both being 85 μm.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] The TSV-based dual-layer fourth-order cross-coupled SIW filter provided by this invention can be realized using three-dimensional integrated circuits and silicon-based vertical via technology. It overcomes various defects of existing SIW filters based on PCB and LTCC in the high-frequency band, such as poor heat dissipation performance, center frequency shift caused by the different thermal expansion coefficients of ceramic substrate and conduction band metal, unsuitability for on-chip integration, and large insertion loss in the terahertz band. As a key component of three-dimensional integrated circuits, through-silicon vias have advantages such as high-precision trench etching and metal filling at the micron level, as well as easy integration with standard CMOS ICs, making TSV-based SIW filters a good candidate for the miniaturization and integration of passive devices.

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of a TSV-based two-layer fourth-order cross-coupled SIW filter provided in an embodiment of the present invention;

[0025] Figure 2 This is a top view of the first metal layer provided in an embodiment of the present invention;

[0026] Figure 3 This is a top view of the first substrate layer provided in an embodiment of the present invention;

[0027] Figure 4 This is a top view of the second metal layer provided in an embodiment of the present invention;

[0028] Figure 5This is a top view of the second substrate layer provided in an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of the nth-order cross-coupled resonant circuit provided in an embodiment of the present invention;

[0030] Figure 7 This is the equivalent two-port network diagram of the cross-coupled resonant circuit provided in the embodiments of the present invention;

[0031] Figure 8 This is a topology diagram of a fourth-order cross-coupled SIW filter provided in an embodiment of the present invention;

[0032] Figure 9 This is a simulation diagram of the optimal S-curve of the dual-layer fourth-order cross-coupled SIW filter provided in an embodiment of the present invention. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0034] Figure 1 This is a schematic diagram of a TSV-based two-layer fourth-order cross-coupled SIW filter provided in an embodiment of the present invention. Figure 1 As shown, this embodiment of the invention provides a TSV-based two-layer fourth-order cross-coupled SIW filter, comprising:

[0035] The first metal layer 1 includes an input port 101 and an output port 102;

[0036] The first substrate layer 2 is located on one side of the first metal layer 1 and includes a plurality of first through holes. The plurality of first through holes form a first resonant cavity 201 and a second resonant cavity 202, and the first resonant cavity 201 and the second resonant cavity 202 are magnetically coupled through a shared sidewall window.

[0037] The second metal layer 3 is located on the side of the first substrate layer 2 away from the first metal layer 1, and includes a first groove 301 and a second groove 302;

[0038] The second substrate layer 4 is located on the side of the second metal layer 3 away from the first substrate layer 2, and includes a plurality of second through holes. The plurality of second through holes form a third resonant cavity 401 and a fourth resonant cavity 402. The third resonant cavity 401 and the fourth resonant cavity 402 generate magnetic coupling through a shared sidewall window. The first groove 301 is used to introduce electrical coupling between the first resonant cavity 201 and the third resonant cavity 401, and the second groove 302 is used to introduce magnetic coupling between the second resonant cavity 202 and the fourth resonant cavity 402.

[0039] The third metal layer 5 is located on the side of the second substrate layer 4 away from the second metal layer 3.

[0040] Specifically, such as Figure 1 As shown, the TSV-based dual-layer fourth-order cross-coupled SIW filter comprises, from top to bottom: a first metal layer 1, a first substrate layer 2, a second metal layer 3, a second substrate layer 4, and a third metal layer 5. The first metal layer 1 includes an input port 101 and an output port 102. The first substrate layer 2 includes multiple first vias, which are evenly arranged to form a first resonant cavity 201 and a second resonant cavity 202. The two resonant cavities are magnetically coupled through a shared sidewall window, which is the notch on the shared edge of the first resonant cavity 201 and the second resonant cavity 202.

[0041] Furthermore, the second metal layer 3 includes a first groove 301 and a second groove 302, and the second substrate layer 4 includes a third resonant cavity 401 and a fourth resonant cavity 402. Similar to the first resonant cavity 201 and the second resonant cavity 202, the third resonant cavity 401 and the fourth resonant cavity 402 also generate magnetic coupling through a shared sidewall window. The first groove 301 is used to introduce electrical coupling between the first resonant cavity 201 and the third resonant cavity 401, and the second groove 302 is used to introduce magnetic coupling between the second resonant cavity 202 and the fourth resonant cavity 402.

[0042] Optionally, both the input port 101 and the output port 102 are in the form of microstrip lines. In the first direction, the input port 101 and the output port 102 are located on both sides of the first metal layer 1, respectively. The first direction is the direction from the first resonant cavity 201 to the second resonant cavity 202.

[0043] Figure 2 This is a top view of the first metal layer 1 provided in an embodiment of the present invention. Figure 2 As shown, in this embodiment, the input port 101 and output port 102 of the first metal layer 1 can selectively use microstrip lines. In the first direction, the input port 101 and output port 102 are located on opposite sides of the first metal layer 1, that is, in Figure 1 From the view shown, the input port 101 and the output port 102 are located on the left and right sides of the first metal layer 1.

[0044] Optionally, in the above-mentioned dual-layer fourth-order cross-coupled SIW filter, the first resonant cavity 201 includes a first coupling window, and the second resonant cavity 202 includes a second coupling window. In the direction perpendicular to the plane where the first substrate layer 2 is located, the orthographic projection of the input port 101 overlaps with the orthographic projection of the first coupling window, and the orthographic projection of the output port 102 overlaps with the orthographic projection of the second coupling window.

[0045] Figure 3 This is a top view of the first substrate layer 2 provided in an embodiment of the present invention. Please refer to... Figure 1 , 3The first resonant cavity 201 and the second resonant cavity 202 also include coupling windows, in Figure 3 From the shown perspective, the first coupling window of the first resonant cavity 201 is the notch on its left side, and the second coupling window of the second resonant cavity 202 is the notch on its right side. In the direction perpendicular to the plane of the first substrate layer 2, the orthographic projection of the input port 101 overlaps with the orthographic projection of the first coupling window, and the orthographic projection of the output port 102 overlaps with the orthographic projection of the second coupling window. This avoids the failure of the port transition structure due to contact between the input microstrip line and the output microstrip line and the first via in the first substrate layer 2.

[0046] Figure 4 This is a top view of the second metal layer 3 provided in an embodiment of the present invention. Please refer to... Figure 1 , 4 The first groove 301 and the second groove 302 are filled with silicon. In a direction perpendicular to the plane of the second metal layer 3, the orthographic projection of the first groove 301 is circular, and the orthographic projection of the center of the circle coincides with the orthographic projection of the center of the first resonant cavity 201. It should be understood that by creating the first groove 301 and the second groove 302 on the second metal layer 3, electric or magnetic fields can be transferred through these grooves. Furthermore, considering the need to achieve electrical or magnetic coupling, in this embodiment, silicon, the same material as the first substrate layer 2 and the second substrate layer 4, is selected for filling. In addition, regarding the electric field distribution of the first resonant cavity 201, the electric field is strongest at its center and gradually weakens towards the periphery. If the center of the circular first groove 301 does not coincide with the center of the first resonant cavity 201, the required electrical coupling strength cannot be obtained.

[0047] Please continue reading Figure 4 The second groove 302 includes a first sub-groove 302a and a second sub-groove 302b, and the second resonant cavity 202 includes a first side and a second side disposed opposite to each other in a second direction;

[0048] In the direction perpendicular to the plane of the second metal layer 3, the orthographic projections of the first sub-groove 302a and the second sub-groove 302b are both rectangles. The distance between the orthographic projection of the first sub-groove 302a and the orthographic projection of the first side and the distance between the orthographic projection of the second sub-groove 302b and the orthographic projection of the second side are equal. The second direction is perpendicular to the first direction, and both the first and second directions are parallel to the plane of the second metal layer 3.

[0049] Specifically, in this embodiment, the direction from the first resonant cavity 201 to the second resonant cavity 202 is taken as the first direction, and the second direction is perpendicular to the first direction, and both are parallel to the plane where the second metal layer 3 is located. Therefore, in the second direction, the second resonant cavity 202 includes a first side and a second side disposed opposite to each other, that is, in... Figure 3From a certain perspective, the upper and lower edges of the second resonant cavity 202. Optionally, in the direction perpendicular to the plane where the second metal layer 3 is located, the orthographic projections of the first sub-groove 302a and the second sub-groove 302b are both rectangles, and the distance between the orthographic projection of the first sub-groove 302a and the orthographic projection of the first side, and the distance between the orthographic projection of the second sub-groove 302b and the orthographic projection of the second side are equal, such as 60μm.

[0050] Figure 5 This is a top view of the second substrate layer 4 provided in an embodiment of the present invention. Figure 5 As shown, the second substrate layer 4 includes a third resonant cavity 401 and a fourth resonant cavity 402 formed by a plurality of second through holes arranged uniformly. Since the structure of the second substrate layer 4 is similar to that of the first substrate layer 2, it will not be described in detail here.

[0051] Optionally, the first metal layer 1, the second metal layer 3, and the third metal layer 5 have the same thickness, which is 5 μm.

[0052] The materials for the first, second, and third metal layers can be copper.

[0053] In addition, the first substrate layer and the second substrate layer have the same thickness, both being 85 μm.

[0054] The resonant cavity is the basic unit of a filter. Energy is transferred between resonant cavities through electromagnetic coupling, and the performance of the filter is closely related to the coupling. Electromagnetic coupling includes three types: magnetic coupling, electric coupling, and hybrid coupling. The coupling strength is generally reflected by the coupling coefficient, which can be represented by a coupling matrix. Therefore, determining the coupling matrix is ​​crucial for designing SIW filters.

[0055] Figure 6 This is a schematic diagram of the structure of an nth-order cross-coupled resonant circuit provided in an embodiment of the present invention. Please refer to [link / reference]. Figure 6 This cross-coupled resonant circuit consists of n resonant units, M ij This represents the coupling coefficient between the i-th resonant unit and the j-th resonant unit. The circuit can be equivalently represented as follows: Figure 7 The two-port network shown.

[0056] According to Kirchhoff's circuit laws, it can be... Figure 6 The loop equations in the circuit shown are expressed as equation (1):

[0057]

[0058] Equation (1) is transformed into matrix form to obtain equation (2):

[0059] [Z][i]=[e] (2)

[0060] Among them, [i]T =[i1,i2,…,i n ],[e] T =[e s [Z] is an n×n impedance matrix with the following values:

[0061]

[0062] Where L = L1 = L2 = … = L n C = C1 = C2 = ... = C n .

[0063] Similarly, equation (2) can also be expressed in the form of equation (4):

[0064]

[0065] Wherein, FBW = Δw / w0 represents the relative bandwidth, and Δw represents the bandwidth corresponding to when the signal energy attenuation reaches 3dB.

[0066] according to Figure 6 The sum of equations L = L1 = L2 = ... = L n The magnetic coupling coefficient M can be obtained ij It can be expressed as equation (5):

[0067]

[0068] Input and output resistors R1, R n External quality factor Q of input and output e1 Q en The following relationships exist:

[0069]

[0070]

[0071] Combining equations (2) to (7), the normalized impedance matrix of the bandpass filter is finally obtained after simplification. It is expressed as follows:

[0072]

[0073] Where, q ei =Q ei ·FBW(i=1,n) is the normalized external quality factor, m ij =M ij / FBW is the normalized coupling coefficient.

[0074] Currently, the coupling matrix is ​​often calculated using an "n+2" coupling matrix, which can be directly calculated by the Couplefil software, in the following form:

[0075]

[0076] [m] is the coupling matrix The extension not only enables direct or cross-coupling between resonators, but also coupling between the source or load and each resonator, possessing all the information required for filter synthesis.

[0077] The design process of the TSV-based two-layer fourth-order cross-coupled SIW filter provided by the present invention will be further explained below in conjunction with the above analysis.

[0078] Since the SIW filter provided in this invention is mainly used in wireless communication fields with high-frequency and high-bandwidth backgrounds, the relevant parameters of the SIW filter are set as follows: order 4, center frequency 110 GHz, 3dB bandwidth 3.3 GHz, return loss greater than 25 dB, and insertion loss less than 3 dB. To further improve the out-of-band rejection performance of this filter, a finite transmission zero is introduced near both 106 GHz and 114 GHz frequencies. For details, please refer to [link to relevant documentation]. Figure 1 The second metal layer 3 shown has electrical coupling generated by circular grooves, while magnetic coupling is generated by two rectangular grooves near the TSV.

[0079] Figure 8 This is a topological diagram of a fourth-order cross-coupled SIW filter provided in an embodiment of the present invention. Figure 8 As shown, based on the transmission zeros and filter order designed in the above steps, the topology of the fourth-order cross-coupled SIW filter is extracted. S represents the input port, L represents the output port, and "1", "2", "3", and "4" represent the first resonant cavity 201, the second resonant cavity 202, the third resonant cavity 401, and the fourth resonant cavity 402, respectively. The filter's performance parameters and topology are input into the CoupleFil software to obtain the normalized coupling matrix of the SIW filter.

[0080]

[0081] Since the normalized coupling matrix [m] is not applicable to actual operations, it is necessary to perform the reverse operation of equations (3) to (9) to obtain the final coupling matrix used in actual applications:

[0082]

[0083] After establishing models for each module of the SIW filter, parameter extraction was performed. The extraction results are as follows: Parameters to be optimized (gap_y1, gap_y2, gap_y3, gap_y4, w12, w34, R_ele, K, m0) = (110, 110, 110, 110, 127, 199, 78, 160, 204) (unit: micrometers, μm); Fixed parameters (gap_x1, gap_x4, w0, n0, ... tsv_d, P, T) = (100, 100, 68, 30, 40, 30, 60) (unit: micrometers, μm), where gap_y1 represents the spacing of the first through holes in the first resonant cavity 201 in the first direction, gap_y2 represents the spacing of the first through holes in the second resonant cavity 202 in the first direction, gap_y4 represents the spacing of the second through holes in the third resonant cavity 401 in the first direction, and gap_y3 represents the spacing of the fourth resonant cavity 401 in the first direction. In 02, the spacing of the second through-hole in the first direction, w12 represents the width of the side wall window shared by the first resonant cavity 201 and the second resonant cavity 202, w34 represents the width of the side wall window shared by the third resonant cavity 401 and the fourth resonant cavity 402, R_ele represents the radius of the first groove 301, K represents the length of the first sub-groove 302a and the second sub-groove 302b in the first direction, m0 represents the depth of the microstrip line groove, gap_x1 represents the spacing of the first through-hole in the first resonant cavity 201 in the second direction, gap_x4 represents the spacing of the first through-hole in the third resonant cavity 401 in the second direction, w0 represents the width of the microstrip line, n0 represents the width of the microstrip line groove, tsv_d represents the diameter of the first through-hole / second through-hole, P represents the width of the first sub-groove 302a and the second sub-groove 302b in the second direction, and T represents the distance between the orthographic projection of the first sub-groove 302a and the orthographic projection of the first side.

[0084] After extracting and summarizing the parameters from the above steps, a SIW filter model is built in HFSS software, and a series of simulations and parameter optimizations are performed. Figure 9 This is a simulation diagram of the optimal S-curve of the dual-layer fourth-order cross-coupled SIW filter provided in an embodiment of the present invention. The corresponding optimal parameters are (gap_y1,gap_y2,gap_y3,gap_y4,w12,w34,R_ele,K,m0)=(109.9907,98.7096,105.0836,110.7303,123.7429,191.2144,80.4643,163.6683,202.0287) (unit: micrometers, μm).

[0085] As can be seen from the above embodiments, the beneficial effects of the present invention are as follows:

[0086] The TSV-based dual-layer fourth-order cross-coupled SIW filter provided by this invention can be realized using three-dimensional integrated circuits and silicon-based vertical via technology. It overcomes various defects of existing SIW filters based on PCB and LTCC in the high-frequency band, such as poor heat dissipation performance, center frequency shift caused by the different thermal expansion coefficients of ceramic substrate and conduction band metal, unsuitability for on-chip integration, and large insertion loss in the terahertz band. As a key component of three-dimensional integrated circuits, through-silicon vias have advantages such as high-precision trench etching and metal filling at the micron level, as well as easy integration with standard CMOS ICs, making TSV-based SIW filters a good candidate for the miniaturization and integration of passive devices.

[0087] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0088] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0089] The use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples" indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0090] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A two-layer fourth-order cross-coupled SIW filter based on TSV, characterized in that, include: The first metal layer includes input ports and output ports; A first substrate layer, located on one side of the first metal layer, includes a plurality of first vias, the plurality of first vias forming a first resonant cavity and a second resonant cavity, and the first resonant cavity and the second resonant cavity are magnetically coupled through a shared sidewall window; The second metal layer is located on the side of the first substrate layer away from the first metal layer, and includes a first groove and a second groove. The second substrate layer, located on the side of the second metal layer away from the first substrate layer, includes a plurality of second vias, the plurality of second vias forming a third resonant cavity and a fourth resonant cavity, and the third resonant cavity and the fourth resonant cavity are magnetically coupled through a shared sidewall window, the first groove is used to introduce electrical coupling between the first resonant cavity and the third resonant cavity, and the second groove is used to introduce magnetic coupling between the second resonant cavity and the fourth resonant cavity. The third metal layer is located on the side of the second substrate layer away from the second metal layer; In the direction perpendicular to the plane of the second metal layer, the orthographic projection of the first groove is a circle, and the orthographic projection of the center of the circle coincides with the orthographic projection of the center of the first resonant cavity. The second groove includes a first sub-groove and a second sub-groove, and the second resonant cavity includes a first side and a second side disposed opposite to each other in a second direction; in a direction perpendicular to the plane where the second metal layer is located, the orthographic projections of the first sub-groove and the second sub-groove are both rectangles, and the distance between the orthographic projection of the first sub-groove and the orthographic projection of the first side and the distance between the orthographic projection of the second sub-groove and the orthographic projection of the second side are equal; wherein, the second direction is perpendicular to the first direction, and both the first direction and the second direction are parallel to the plane where the second metal layer is located.

2. The TSV-based two-layer fourth-order cross-coupled SIW filter according to claim 1, characterized in that, Both the input port and the output port are in the form of microstrip lines. In a first direction, the input port and the output port are located on opposite sides of the first metal layer. The first direction is the direction from the first resonant cavity to the second resonant cavity.

3. The TSV-based two-layer fourth-order cross-coupled SIW filter according to claim 2, characterized in that, The first resonant cavity includes a first coupling window, and the second resonant cavity includes a second coupling window. In a direction perpendicular to the plane where the first substrate layer is located, the orthographic projection of the input port overlaps with the orthographic projection of the first coupling window, and the orthographic projection of the output port overlaps with the orthographic projection of the second coupling window.

4. The TSV-based two-layer fourth-order cross-coupled SIW filter according to claim 1, characterized in that, The first and second grooves are filled with silicon.

5. The TSV-based two-layer fourth-order cross-coupled SIW filter according to claim 1, characterized in that, The first metal layer, the second metal layer, and the third metal layer have the same thickness, which is 5 μm.

6. The TSV-based two-layer fourth-order cross-coupled SIW filter according to claim 5, characterized in that, The first metal layer, the second metal layer, and the third metal layer are made of copper.

7. The TSV-based two-layer fourth-order cross-coupled SIW filter according to claim 1, characterized in that, The first substrate layer and the second substrate layer have the same thickness, both being 85 μm.

Images