High q resonator filter based on ltcc technology

Abstract

The application relates to a high-Q resonant filter based on an LTCC process, the most core part of the architecture is composed of a resonant unit A, a resonant unit B and an inter-stage coupling unit to form a basic resonant coupling filter unit, wherein the resonant unit innovatively introduces multiple hole columns in parallel to form an equivalent large via, thereby greatly improving the Q value of resonant inductance, and by adjusting the size of the hole column coil and the distance between the hole column coils, the magnetic coupling strength of adjacent resonant units can be adjusted, and by further adjusting the size of the inter-stage coupling capacitor, the overall coupling strength of the inter-stage coupling unit can be flexibly adjusted, and the cross-stage coupling capacitor can be flexibly adjusted to deepen the single-side rectangular coefficient; in addition, the application adopts a mirror-symmetrical layout mode in the internal structure, reasonably optimizes the internal space structure, reduces the design and debugging difficulty and avoids errors in the production process, so that the high-Q LC resonant coupling filter has better controllability and a better rectangular coefficient.

Description

Technical Field

[0001] This invention relates to the field of filter technology, specifically to a high-Q resonant filter based on LTCC technology. Background Technology

[0002] With the rapid development of communication technology, the global communications industry is gradually entering the 5G era.

[0003] LTCC, or Low Temperature Co-sintered Ceramic, allows for the encapsulation of three major passive components (resistors, capacitors, and inductors) and various other passive components (such as filters and transformers) within a multilayer wiring substrate. These components can then be integrated with active components (such as power MOSFETs, transistors, and IC modules) to form a complete circuit system. It is now widely used in various types of mobile phones, Bluetooth, GPS modules, WLAN modules, and Wi-Fi modules. Furthermore, due to its high reliability, its applications in automotive electronics, communications, aerospace and military, microelectromechanical systems (MEMS), and sensor technology are also increasing.

[0004] With the advent of the 5G era, LTCC plays an important role because it can withstand high current and high temperature. From mobile phones and wearable devices to automotive applications, RF components are needed. As a key component, LTCC is driven by the fact that the number of 5G mobile phones used has increased by 40% compared to 4G, which has greatly increased the demand for LTCC.

[0005] There are generally three ways to implement LTCC bandpass filters: the first is the traditional parallel resonant bandpass filter, which is implemented through a parallel resonant unit composed of an inductor and a capacitor; the second is to use distributed capacitor plates, achieving the bandpass filter effect through the coupling between the plates; and the third is to implement it by connecting a high-pass filter and a low-pass filter in series. Each of these three structures has its own advantages and challenges in manufacturing and design. The traditional parallel resonant bandpass filter has deeper near-band rejection than the other two, but its passband insertion loss increases with the increase of parallel resonant units, making signal loss difficult to control. The distributed structure bandpass filter is simple to design, easy to debug, and has balanced electrical performance, but because its structure is mainly achieved through coupling between plates, it has higher requirements for manufacturing processes and is prone to problems during LTCC diaphragm stacking, cutting, and sintering, resulting in poor batch consistency. The bandpass filter using a high-pass filter and a low-pass filter in series has a wide passband, good insertion loss, and high signal fidelity, but poor out-of-band rejection, a complex structure, and is difficult to debug. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide a high-Q resonant filter based on LTCC technology. This filter is simple to design and debug, and has small errors during production.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] A high-Q resonant filter based on LTCC technology includes a substrate, input and output external electrodes, and a ground external electrode. The two input and output external electrodes are disposed on two opposite sides of the substrate, and the two ground external electrodes are disposed on two other opposite sides of the substrate. The substrate is formed by stacking multiple dielectric plates, and the multiple dielectric plates include…

[0009] A first substrate having a first ground layer formed thereon;

[0010] A second substrate is stacked on top of a first substrate, and a first conductor layer, a second conductor layer, a plurality of first conductive via pillars located in the first conductor layer, and a plurality of second conductive via pillars located in the second conductor layer are formed on the second substrate.

[0011] A third substrate is stacked on top of the second substrate, and a third conductor layer is formed on the third substrate;

[0012] A fourth substrate is stacked on top of a third substrate, and a fourth conductor layer and a fifth conductor layer are formed on the fourth substrate, a plurality of first conductive via pillars located in the fourth conductor layer, and a plurality of second conductive via pillars located in the fifth conductor layer.

[0013] The fifth substrate is stacked on top of the fourth substrate, and a second ground layer is formed thereon. The two ends of the second ground layer extend out to output electrodes and input electrodes that are coupled to input and output external electrodes, respectively. The multiple first conductive via posts and multiple second conductive via posts on the fourth substrate are all connected to the second ground layer.

[0014] In this configuration, multiple first conductive vias in multiple dielectric plates are connected to form a first resonant inductor L1, and multiple second conductive vias in multiple dielectric plates are connected to form a second resonant inductor L2. A first conductor layer and a first ground layer form a grounding capacitor C1, and a second conductor layer and a first ground layer form a grounding capacitor C2. The first resonant inductor L1 and the grounding capacitor C1 are connected in parallel to form a resonant unit A, and the second resonant inductor L2 and the grounding capacitor C2 form a resonant unit B. The resonant unit A and the resonant unit B are mirror images of each other.

[0015] Among them, the third conductor layer forms a coupling capacitor C12 with the fourth and fifth conductor layers.

[0016] As a preferred embodiment: the first resonant inductor L1 is composed of two groups of conductive vias spaced apart, each group of conductive vias including seven first conductive vias; the second resonant inductor L2 is also composed of two groups of conductive vias spaced apart, each group of conductive vias including seven second conductive vias.

[0017] As a preferred embodiment, a sixth substrate is provided between the fourth substrate and the fifth substrate. An inductive coupling layer is formed on the sixth substrate, and one end of the inductive coupling layer is connected to the grounded external electrode, while the other end is open to separate the first resonant inductor L1 and the second resonant inductor L2.

[0018] As a preferred embodiment, the second substrate is further provided with a sixth conductor layer and a seventh conductor layer, which together with the first ground layer form grounding capacitance C3 and grounding capacitance C4, respectively.

[0019] As a preferred embodiment, it also includes a third resonant inductor L3 and a fourth resonant inductor L4. The third resonant inductor L3 is composed of multiple third conductive via posts, and the fourth resonant inductor L4 is composed of multiple fourth conductive via posts. One end of the multiple third conductive via posts is connected to the sixth conductor layer, and the other end is connected to the second ground layer. One end of the multiple fourth conductive via posts is connected to the seventh conductor layer, and the other end is connected to the second ground layer.

[0020] As a preferred embodiment, a seventh substrate is further provided between the fourth substrate and the fifth substrate, and an eighth conductor layer connected to the third resonant inductor L3, a ninth conductor layer connected to the first resonant inductor L1, a tenth conductor layer connected to the second resonant inductor L2, and an eleventh conductor layer connected to the fourth resonant inductor L4 are formed on the seventh substrate.

[0021] As a preferred embodiment: an eighth substrate is further provided between the seventh substrate and the fourth substrate, and a twelfth conductor layer and a thirteenth conductor layer are formed on the eighth substrate. The twelfth conductor layer forms a coupling capacitor C23 with the eighth conductor layer and the tenth conductor layer, and the thirteenth conductor layer forms a coupling capacitor C14 with the ninth conductor layer and the eleventh conductor layer.

[0022] As a preferred embodiment: a ninth substrate is further provided between the seventh substrate and the fifth substrate, and a fourteenth conductor layer is formed on the ninth substrate. The fourteenth conductor layer forms a coupling capacitor C34 with the eighth conductor layer and the eleventh conductor layer.

[0023] As a preferred embodiment: the fourth conductor layer forms a coupling capacitor C13 with the first conductor layer and the sixth conductor layer, and the fifth conductor layer forms a coupling capacitor C24 with the second conductor layer and the seventh conductive layer.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] The core of the filter architecture of this invention consists of resonant unit A, resonant unit B, and interstage coupling unit forming a basic resonant coupled filter unit. The order can be increased by referring to this core design unit, and a deeper out-of-band suppression can be achieved through a specific topology. The resonant unit innovatively introduces a multi-hole column in parallel to form an equivalent large via, thereby significantly improving the Q value of the resonant inductor. Furthermore, the magnetic coupling strength of adjacent resonant units can be adjusted by changing the size of the hole column rings and their distance. Combined with adjusting the size of the interstage coupling capacitor, the overall coupling strength of the interstage coupling unit can be flexibly adjusted. The cross-order coupling capacitor can also be flexibly adjusted to deepen the single-sided rectangular coefficient. In addition, this invention adopts a mirror-symmetric layout in its internal structure, rationally optimizing the internal space structure, reducing design and debugging difficulty, and avoiding errors that may occur during production. All of these factors make the high-Q LC resonant coupled filter of this invention more operable and possess a superior rectangular coefficient. Attached Figure Description

[0026] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute a limitation thereof.

[0027] Figure 1 This is a schematic diagram of the overall structure of the filter of the present invention;

[0028] Figure 2 This is a schematic diagram of the first internal structure of the filter of the present invention;

[0029] Figure 3 This is a schematic diagram of the second internal structure of the filter of the present invention;

[0030] Figure 4 The diagram shows the equivalent circuits corresponding to the first and second internal structures of the filter of the present invention.

[0031] Figure 5 This is a schematic diagram of the third internal structure of the filter of the present invention;

[0032] Figure 6 This is a schematic diagram of the equivalent circuit corresponding to the third internal structure of the filter of the present invention.

[0033] Figures 7 to 15 This is a schematic diagram of the ninth substrate to the first substrate of the filter of the present invention;

[0034] Figure 16 This is a frequency response curve of the filter of the present invention. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0036] To more clearly and thoroughly illustrate the technical embodiments of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0037] like Figure 1 and Figure 2 As shown, a high-Q resonant filter based on LTCC technology includes a substrate 1, input and output external electrodes 2, and a grounded external electrode 3. The two input and output external electrodes 2 are disposed on two opposite sides of the substrate 1, and the two grounded external electrodes 3 are disposed on two other opposite sides of the substrate 1. The substrate 1 is characterized by being formed by stacking multiple dielectric plates, and these multiple dielectric plates include…

[0038] A first substrate having a first ground layer 9 formed thereon;

[0039] The second substrate is stacked on top of the first substrate, and a first conductor layer 6 and a second conductor layer 7 are formed on the second substrate, a plurality of first conductive via pillars 4 located in the first conductor layer 6, and a plurality of second conductive via pillars 5 located in the second conductor layer 7.

[0040] A third substrate is stacked on top of the second substrate, and a third conductor layer 8 is formed on the third substrate;

[0041] A fourth substrate is stacked on top of a third substrate, and a fourth conductor layer 17 and a fifth conductor layer 18 are formed on the fourth substrate, a plurality of first conductive via pillars 4 located in the fourth conductor layer 17, and a plurality of second conductive via pillars 5 located in the fifth conductor layer 18.

[0042] The fifth substrate is stacked on top of the fourth substrate, and a second ground layer 10 is formed thereon. The two ends of the second ground layer 10 extend out to the output electrode 11 and the input electrode 12, which are coupled to the input and output external electrodes 2, respectively. The multiple first conductive via pillars 4 and multiple second conductive via pillars 5 on the fourth substrate are all connected to the second ground layer 10.

[0043] In this configuration, multiple first conductive vias 4 in multiple dielectric plates are connected to form a first resonant inductor L1, and multiple second conductive vias 5 in multiple dielectric plates are connected to form a second resonant inductor L2. A first conductor layer 6 and a first ground layer 9 form a ground capacitor C1, a second conductor layer 7 and a first ground layer 9 form a ground capacitor C2, the first resonant inductor L1 and the ground capacitor C1 are connected in parallel to form a resonant unit A, and the second resonant inductor L2 and the ground capacitor C2 form a resonant unit B. The resonant unit A and the resonant unit B are mirror images of each other.

[0044] The value of the first resonant inductor L1 can be adjusted by the number and length of vias; the value of the grounding capacitor C1 can be adjusted by adjusting the spacing between the first conductor layer 6 and the first ground layer 9 or by adjusting the area of ​​the first conductor layer 6. The resonant frequency of resonant unit A is adjusted by integrating the values ​​of the resonant inductor L1 and the grounding capacitor C1. Resonant unit B is obtained by mirroring resonant unit A, which helps to reduce the overall adjustment difficulty of the filter.

[0045] The third conductor layer 8, the fourth conductor layer 17, and the fifth conductor layer 18 form a coupling capacitor C12. The magnetic coupling formed between the conductive via pillars of resonant unit A and second resonant unit B, along with the coupling capacitor C12, forms an integral coupling unit. The capacitance can be adjusted by changing the area of ​​the coupling capacitor C12 to adjust the capacitive coupling of this coupling unit. The magnetic coupling strength between the inductor pillars is adjusted by the spacing and shape of the conductive via pillars of resonant unit A and resonant unit B to change the magnetic coupling strength between the two resonant units.

[0046] The coupling unit described herein is a main adjustment unit. This main adjustment unit can adjust the coupling strength by adjusting the strength of magnetic and capacitive coupling, thereby adjusting the bandwidth and frequency of the high-Q LC resonant coupling filter. In this way, the position of its transmission zero point can also be adjusted arbitrarily, effectively suppressing spurious signals at different frequency points. In other words, the high-Q LC resonant filter of this invention has advantages such as high operability and high suppression.

[0047] The first resonant inductor L1 consists of two groups of conductive via pillars spaced apart, each group including seven first conductive via pillars 4; the second resonant inductor L2 also consists of two groups of conductive via pillars spaced apart, each group including seven second conductive via pillars 5. Here, a multi-via pillar parallel inductor architecture is innovatively used, which greatly increases the Q value of the inductor; the first resonant inductor L1 in resonant unit A is formed by multiple conductive via pillars arranged in parallel to form a large ring, and the second resonant inductor L2 in resonant unit B is also formed by multiple conductive via pillars arranged in parallel to form a large ring. The three-dimensional patterns of resonant unit A and resonant unit B are consistent and symmetrical, which is more conducive to adjusting the performance of the filter.

[0048] like Figure 3 As shown, a sixth substrate is provided between the fourth and fifth substrates. An inductive coupling layer 200 is formed on the sixth substrate, with one end of the inductive coupling layer 200 connected to the grounded external electrode 3, and the other end open-circuited to separate the first resonant inductor L1 and the second resonant inductor L2. The addition of an inductive coupling layer between the two LC resonant units makes it easier to form transmission zeros in the high-frequency near-band of the filter passband, and it is frequently used to filter out high-frequency spurious signals outside the passband.

[0049] The equivalent circuits for the two LC resonant coupling methods described above are as follows: Figure 4 As shown, the positions of the transmission zeros will differ. The two implementation methods can flexibly adjust the position of the out-of-band transmission zeros, making the high-Q LC resonant filter of this invention more operable and with higher suppression.

[0050] like Figures 5 to 15 As shown, the second substrate also has a sixth conductor layer 15 and a seventh conductor layer 16. The sixth conductor layer 15 and the seventh conductor layer 16 form grounding capacitors C3 and C4 with the first grounding layer 9, respectively. The filter also includes a third resonant inductor L3 and a fourth resonant inductor L4. The third resonant inductor L3 is composed of multiple third conductive via pillars 13, and the fourth resonant inductor L4 is composed of multiple fourth conductive via pillars 14. One end of the multiple third conductive via pillars 13 is connected to the sixth conductor layer 15, and the other end is connected to the second grounding layer 10. One end of the multiple fourth conductive via pillars 14 is connected to the seventh conductor layer 16, and the other end is connected to the second grounding layer 10.

[0051] A seventh substrate is also provided between the fourth substrate and the fifth substrate. An eighth conductor layer 22 connected to the third resonant inductor L3, a ninth conductor layer 23 connected to the first resonant inductor L1, a tenth conductor layer 24 connected to the second resonant inductor L2, and an eleventh conductor layer 25 connected to the fourth resonant inductor L4 are formed on the seventh substrate.

[0052] An eighth substrate is provided between the seventh substrate and the fourth substrate. A twelfth conductor layer 19 and a thirteenth conductor layer 20 are formed on the eighth substrate. The twelfth conductor layer 19 forms a coupling capacitor C23 with the eighth conductor layer 22 and the tenth conductor layer 24. The thirteenth conductor layer 20 forms a coupling capacitor C14 with the ninth conductor layer 23 and the eleventh conductor layer 25.

[0053] A ninth substrate is provided between the seventh substrate and the fifth substrate. A fourteenth conductor layer 21 is formed on the ninth substrate. The fourteenth conductor layer 21 forms a coupling capacitor C34 with the eighth conductor layer 22 and the eleventh conductor layer 25.

[0054] The fourth conductor layer 17 forms a coupling capacitor C13 with the first conductor layer 6 and the sixth conductor layer 15, and the fifth conductor layer 18 forms a coupling capacitor C24 with the second conductor layer 7 and the seventh conductive layer 16.

[0055] The core of the filter architecture of this invention consists of the aforementioned resonant unit A and resonant unit B, along with interstage coupling units, forming a basic resonant coupled filter unit. Referring to the core design unit described above, an additional order is added to design a filter comprising four LC resonant units and three main coupling adjustment units. This design flexibly utilizes the core design unit, but the number and arrangement of vias (inductors) in the resonant units differ, resulting in different resonant frequencies. The coupling adjustment units between adjacent LC resonant units in this embodiment also refer to the core design. Furthermore, to increase the suppression capability at low frequencies outside the passband, coupling capacitors are added between resonant units A and C, and between resonant units B and D, as well as between resonant units A and D. This embodiment has four LC resonant units, which, combined with different coupling adjustment units between the resonant units, can achieve a wider bandwidth and deeper near-band suppression capability at low frequencies outside the passband. The corresponding frequency response diagram is shown below. Figure 16 As shown.

[0056] The embodiments described above are preferred embodiments of the present invention and are not intended to limit the invention to the above-described embodiments. Based on the embodiments of the present invention, any modifications, equivalent substitutions, or improvements made by those skilled in the art without inventive effort to obtain other embodiments should be included within the scope of protection set forth in the claims.

Claims

1. A high Q resonator filter based on LTCC technology, comprising a substrate (1), input / output outer electrodes (2) and ground outer electrodes (3), two input / output outer electrodes (2) are arranged on two opposite sides of the substrate (1), and two ground outer electrodes (3) are arranged on the other two opposite sides of the substrate (1), characterized in that: The base body (1) is formed by stacking a plurality of dielectric plates, and the plurality of dielectric plates comprise, a first substrate having a first ground layer (9) formed thereon; a second substrate stacked above the first substrate, and the second substrate having a first conductor layer (6), a second conductor layer (7), a plurality of first conductive via columns (4) in the first conductor layer (6), and a plurality of second conductive via columns (5) in the second conductor layer (7) formed thereon; a third substrate stacked above the second substrate, and the third substrate having a third conductor layer (8) formed thereon; a fourth substrate stacked above the third substrate, and the fourth substrate having a fourth conductor layer (17), a fifth conductor layer (18), a plurality of first conductive via columns (4) in the fourth conductor layer (17), and a plurality of second conductive via columns (5) in the fifth conductor layer (18) formed thereon; a fifth substrate stacked above the fourth substrate, and the fifth substrate having a second ground layer (10) formed thereon, and the two ends of the second ground layer (10) extending out of output electrodes (11) and input electrodes (12) coupled with input and output external electrodes (2), and the plurality of first conductive via columns (4) and the plurality of second conductive via columns (5) on the fourth substrate are connected to the second ground layer (10); wherein the plurality of first conductive via columns (4) in the plurality of dielectric plates are correspondingly connected to form a first resonant inductor L1, the plurality of second conductive via columns (5) in the plurality of dielectric plates are correspondingly connected to form a second resonant inductor L2, the first conductor layer (6) and the first ground layer (9) form a lower ground capacitor C1, the second conductor layer (7) and the first ground layer (9) form a lower ground capacitor C2, the first resonant inductor L1 and the lower ground capacitor C1 are connected in parallel to form a resonant unit A, the second resonant inductor L2 and the lower ground capacitor C2 form a resonant unit B, and the resonant unit A and the resonant unit B are arranged in mirror image with each other; wherein the third conductor layer (8) and the fourth conductor layer (17) and the fifth conductor layer (18) form a coupling capacitor C12; The first resonant inductor L1 is composed of two groups of conductive via columns arranged at intervals, and each group of conductive via columns includes seven first conductive via columns (4); the second resonant inductor L2 is also composed of two groups of conductive via columns arranged at intervals, and each group of conductive via columns includes seven second conductive via columns (5); The second substrate further comprises a sixth conductor layer (15) and a seventh conductor layer (16), and the sixth conductor layer (15) and the seventh conductor layer (16) form a lower ground capacitor C3 and a lower ground capacitor C4 with the first ground layer (9), respectively; It further comprises a third resonant inductor L3 and a fourth resonant inductor L4, the third resonant inductor L3 is composed of a plurality of third conductive via columns (13), the fourth resonant inductor L4 is composed of a plurality of fourth conductive via columns (14), one end of the plurality of third conductive via columns (13) is connected to the sixth conductor layer (15), and the other end is connected to the second ground layer (10); one end of the plurality of fourth conductive via columns (14) is connected to the seventh conductor layer (16), and the other end is connected to the second ground layer (10).

2. The high Q resonator filter based on LTCC process according to claim 1, characterized in that: The fourth substrate and the fifth substrate are further provided with a sixth substrate, the sixth substrate is provided with an inductive coupling layer (200), one end of the inductive coupling layer (200) is connected to the ground external electrode (3), and the other end is open to separate the first resonant inductor L1 and the second resonant inductor L2.

3. The LTCC process based high Q resonator filter according to claim 1, characterized in that: The fourth substrate and the fifth substrate are further provided with a seventh substrate, the seventh substrate is provided with an eighth conductor layer (22) connected to the third resonant inductor L3, a ninth conductor layer (23) connected to the first resonant inductor L1, a tenth conductor layer (24) connected to the second resonant inductor L2, and an eleventh conductor layer (25) connected to the fourth resonant inductor L4.

4. The high Q resonator filter based on LTCC process according to claim 3, characterized in that: The seventh substrate and the fourth substrate are further provided with an eighth substrate, the eighth substrate is provided with a twelfth conductor layer (19) and a thirteenth conductor layer (20), the twelfth conductor layer (19) and the eighth conductor layer (22) form a coupling capacitor C23, and the thirteenth conductor layer (20) and the ninth conductor layer (23) form a coupling capacitor C14.

5. The high Q resonator filter based on LTCC process according to claim 3, characterized in that: The seventh substrate and the fifth substrate are further provided with a ninth substrate, the ninth substrate is provided with a fourteenth conductor layer (21), and the fourteenth conductor layer (21) and the eighth conductor layer (22) form a coupling capacitor C34.

6. The LTCC process based high Q resonator filter according to claim 1, characterized in that: The fourth conductor layer (17) and the first conductor layer (6) form a coupling capacitor C13, and the fifth conductor layer (18) and the second conductor layer (7) form a coupling capacitor C24.

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