A miniaturized high-performance band-pass filter based on LTCC

Abstract

The application discloses a kind of miniaturization high-performance band-pass filters based on LTCC, and the three-dimensional integration of filter is realized by low-temperature co-fired ceramic process technology, from bottom to top includes: the first layer ground layer, it includes ground metal plate;Second via layer, it includes two vias;The third layer to the eleventh layer are capacitor layer, wherein the third layer includes four transmission lines, two vias, the rest of each layer includes four transmission lines, four vias;The twelfth layer is inductance layer, it includes two transmission lines, four vias;The thirteenth layer is via layer, it includes two vias;The fourteenth layer and the fifteenth layer are capacitor layer, wherein the fourteenth layer includes two metal plates, two vias, the fifteenth layer includes two short transmission lines and two metal plates;The sixteenth layer is packaging layer, including four short transmission lines, respectively with input and output port and ground port are connected.The filter of the application has low insertion loss, good return loss, small volume, high integration, simple design and easy processing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of microwave transmission devices, and particularly relates to a miniaturized high-performance LTCC band-pass filter with multiple controllable transmission zeros. BACKGROUND

[0002] With the rapid development of 5G wireless communication technology and the continuous emergence of new materials and new processes, the performance indicators of various types of passive devices for communication equipment are proposed to be more stringent standards, so that microwave, millimeter wave and radio frequency circuits are highly integrated and the volume is getting smaller and smaller. Using LTCC technology to realize the passive devices in the radio frequency module is a relatively mainstream integrated technology for passive devices at present. Such passive devices can well meet the miniaturization requirements and can easily achieve low cost, high performance and small size design requirements. In addition, as a limited resource, the microwave frequency band is divided more and more finely, and the frequency band utilization rate is continuously improved, resulting in a relatively crowded frequency band, and the frequency interval between various communication systems is also getting smaller and smaller, which is also a test of the performance indicators of the filter. Therefore, researching a new filter topology circuit and increasing controllable transmission zeros in the stop band can achieve high suppression of specific frequency bands in the stop band, and using spatial coupling instead of direct coupling can further reduce the overall size of the filter, which can fundamentally solve this series of problems. SUMMARY

[0003] The application aims to provide a band-pass filter with simple structure, small volume, low insertion loss in passband, and high suppression of multiple specific frequency bands in stop band.

[0004] The technical solution for achieving the application is as follows: a miniaturized high-performance band-pass filter based on LTCC, comprising a first ground layer, a second via layer, third to eleventh capacitor layers, a twelfth inductor layer, a thirteenth via layer, fourteenth and fifteenth capacitor layers, and a sixteenth packaging layer arranged from bottom to top; wherein,

[0005] The first ground layer comprises a first metal plate;

[0006] The second via layer comprises a second via of the second layer and a fourth via of the second layer, one end of the second via of the second layer is connected with the first metal plate of the first layer, and the other end thereof is connected with the first transmission line of the third layer through the second via of the third layer, one end of the fourth via of the second layer is connected with the first metal plate of the first layer, and the other end thereof is connected with the third transmission line of the third layer through the fourth via of the third layer, the radius and length of the second via and the fourth via can be changed to adjust the inductance value and further adjust the position of the transmission zero point;

[0007] The third layer to eleventh layer capacitor layer includes the first transmission line of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer, the second transmission line of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer, the third transmission line of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer, the fourth transmission line of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer, the fifth transmission line of the fourth layer, the sixth layer, the eighth layer and the tenth layer, the sixth transmission line of the fourth layer, the sixth layer, the eighth layer and the tenth layer, the seventh transmission line of the fourth layer, the sixth layer, the eighth layer and the tenth layer, the eighth transmission line of the fourth layer, the sixth layer, the eighth layer and the tenth layer, the first via hole of the fourth layer to the eleventh layer, the second via hole of the third layer to the eleventh layer, the third via hole of the fourth layer to the eleventh layer, the fourth via hole of the third layer to the eleventh layer, the first transmission line of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer is connected with the sixth transmission line of the fourth layer, the sixth layer, the eighth layer and the tenth layer through the second via hole of the fourth layer to the eleventh layer, the second transmission line of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer is connected with the fifth transmission line of the fourth layer, the sixth layer, the eighth layer and the tenth layer through the first via hole of the fourth layer to the eleventh layer, the third transmission line of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer is connected with the eighth transmission line of the fourth layer, the sixth layer, the eighth layer and the tenth layer through the fourth via hole of the fourth layer to the eleventh layer, the fourth transmission line of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer is connected with the seventh transmission line of the fourth layer, the sixth layer, the eighth layer and the tenth layer through the third via hole of the fourth layer to the eleventh layer, which together constitute horizontal-vertical interdigital capacitor.

[0008] The twelfth layer inductor layer includes the ninth transmission line, the tenth transmission line, the first via hole of the twelfth layer, the second via hole of the twelfth layer, the third via hole of the twelfth layer, the fourth via hole of the twelfth layer, one end of the first via hole of the twelfth layer is connected with the second transmission line of the eleventh layer, and the other end is connected with the ninth transmission line of the thirteenth layer, one end of the second via hole of the twelfth layer is connected with the first transmission line of the eleventh layer, and the other end is connected with the ninth transmission line of the thirteenth layer, one end of the third via hole of the twelfth layer is connected with the fourth transmission line of the eleventh layer, and the other end is connected with the tenth transmission line of the thirteenth layer, one end of the fourth via hole of the twelfth layer is connected with the third transmission line of the eleventh layer, and the other end is connected with the tenth transmission line of the thirteenth layer, the adjacent coupling part of the ninth transmission line and the tenth transmission line generates mutual inductance, which realizes space coupling instead of direct coupling.

[0009] The thirteenth via layer includes a first via of the thirteenth layer and a third via of the thirteenth layer, one end of the first via of the thirteenth layer is connected with the ninth transmission line of the twelfth layer, the other end of the first via of the thirteenth layer is connected with the second metal plate of the fourteenth layer through the first via of the fourteenth layer, one end of the third via of the thirteenth layer is connected with the tenth transmission line of the twelfth layer, the other end of the third via of the thirteenth layer is connected with the third metal plate of the fourteenth layer through the third via of the fourteenth layer;

[0010] The fourteenth and fifteenth layer capacitor layers include a first via of the fourteenth layer, a third via of the fourteenth layer, a second metal plate of the fourteenth layer, a third metal plate of the fourteenth layer, an eleventh transmission line of the fifteenth layer, a twelfth transmission line of the fifteenth layer, a fourth metal plate of the fifteenth layer and a fifth metal plate of the fifteenth layer, the fourth metal plate of the fifteenth layer and the fifth metal plate of the fifteenth layer are adjacent to form a planar coupling capacitor, and the planar coupling capacitor also realizes space coupling instead of direct source-load coupling;

[0011] The sixteenth layer encapsulation layer includes a thirteenth transmission line, a fourteenth transmission line, a fifteenth transmission line and a sixteenth transmission line.

[0012] A band-pass filtering method based on the LTCC-based miniaturized high-performance band-pass filter.

[0013] Compared with the prior art, the present application has the following advantages: 1) a new filter topology circuit is adopted to generate multiple controllable transmission zeros; 2) the position of the generated transmission zero is adjusted by adjusting the size of the source-load coupling capacitor and the length of the second via and the fourth via, so that high suppression of certain specific frequency bands in the stop band is realized; 3) a horizontal-vertical interdigital capacitor is adopted to realize a larger capacitance value, thereby reducing the size of the circuit device; 4) space coupling is adopted instead of direct coupling, thereby reducing the number of circuit elements in the actual circuit design, achieving high integration, and further reducing the overall size of the designed band-pass filter.

[0014] The application will be described in further detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 FIG. 1 is a structural schematic diagram of the LTCC-based miniaturized high-performance band-pass filter.

[0016] Figure 2 FIG. 2 is a schematic diagram of the first ground layer of the LTCC-based miniaturized high-performance band-pass filter.

[0017] Figure 3 FIG. 3 is a schematic diagram of the second via layer of the LTCC-based miniaturized high-performance band-pass filter.

[0018] Figure 4The third layer capacitor layer schematic diagram of the LTCC-based miniaturized high-performance band-pass filter.

[0019] Figure 5 The fourth layer, the sixth layer, the eighth layer and the tenth layer capacitor layer schematic diagram of the LTCC-based miniaturized high-performance band-pass filter.

[0020] Figure 6 The fifth layer, the seventh layer, the ninth layer and the eleventh layer capacitor layer schematic diagram of the LTCC-based miniaturized high-performance band-pass filter.

[0021] Figure 7 The twelfth layer inductor layer schematic diagram of the LTCC-based miniaturized high-performance band-pass filter.

[0022] Figure 8 The thirteenth layer via layer schematic diagram of the LTCC-based miniaturized high-performance band-pass filter.

[0023] Figure 9 The fourteenth layer capacitor layer schematic diagram of the LTCC-based miniaturized high-performance band-pass filter.

[0024] Figure 10 The fifteenth layer capacitor layer schematic diagram of the LTCC-based miniaturized high-performance band-pass filter.

[0025] Figure 11 The sixteenth layer package layer schematic diagram of the LTCC-based miniaturized high-performance band-pass filter.

[0026] Figure 12 The novel filter topology circuit diagram of the LTCC-based miniaturized high-performance band-pass filter.

[0027] Figure 13 The principle diagram of generating transmission zero of the LTCC-based miniaturized high-performance band-pass filter.

[0028] Figure 14 The circuit simulation diagram of the novel filter topology circuit of the LTCC-based miniaturized high-performance band-pass filter.

[0029] Figure 15 The circuit simulation diagram of different inductors Lg in the novel filter topology circuit of the LTCC-based miniaturized high-performance band-pass filter.

[0030] Figure 16 The circuit simulation diagram of different capacitors C in the novel filter topology circuit of the LTCC-based miniaturized high-performance band-pass filter.

[0031] Figure 17The application discloses a novel filter topology circuit of a miniaturized high-performance band-pass filter based on LTCC. DETAILED DESCRIPTION

[0032] In combination Figure 1 The application discloses a miniaturized high-performance band-pass filter based on LTCC, which comprises a first ground layer, a second via layer, third to eleventh capacitor layers, a twelfth inductor layer, a thirteenth via layer, fourteenth and fifteenth capacitor layers and a sixteenth packaging layer arranged in sequence from bottom to top.

[0033] In combination Figure 2 The first ground layer comprises a first metal plate GND.

[0034] In combination Figure 3 The second via layer comprises a second via GK2-2 and a fourth via GK4-2 of the second layer, and the inductance value and the position of the transmission zero point can be adjusted by changing the radius and length of the two vias.

[0035] Further, one end of the second via GK2-2 of the second layer is connected with the first metal plate GND of the first layer, and the other end is connected with the first transmission line L1-3 of the third layer through a third via GK-2-3 of the third layer; one end of the fourth via GK4-2 of the second layer is connected with the first metal plate GND of the first layer, and the other end is connected with the third transmission line L3-3 of the third layer through a fourth via GK-4-3 of the third layer.

[0036] In combination Figure 4 , Figure 5 , Figure 6 The third to eleventh capacitor layers comprise first transmission lines L1-3, L1-5, L1-7, L1-9 and L1-11 of the third, fifth, seventh, ninth and eleventh layers, second transmission lines L2-3, L2-5, L2-7, L2-9 and L2-11 of the third, fifth, seventh, ninth and eleventh layers, third transmission lines L3-3, L3-5, L3-7, L3-9 and L3-11 of the third, fifth, seventh, ninth and eleventh layers, fourth transmission lines L4-3, L4-5, L4-7, L4-9 and L4-11 of the third, fifth, seventh, ninth and eleventh layers, fifth transmission lines L5-4, L5-6, L5-8 and L5-10 of the fourth, sixth, eighth and tenth layers, sixth transmission lines L6-4, L6-6, L6-8 and L6-10 of the fourth, sixth, eighth and tenth layers, seventh transmission lines L7-4, L7-6, L7-8 and L7-10 of the fourth, sixth, eighth and tenth layers and eighth transmission lines L8-4, L8-6, L8-8 and L8-10 of the fourth, sixth, eighth and tenth layers.

[0037] The first transmission lines L1-3, L1-5, L1-7, L1-9, and L1-11 of the third, fifth, seventh, ninth, and eleventh layers are connected to the sixth transmission lines L6-4, L6-6, L6-8, and L6-10 of the fourth, sixth, eighth, and tenth layers via the second vias GK2-4, GK2-5, GK2-6, GK2-7, GK2-8, GK2-9, GK2-10, and GK2-11 from the fourth to the eleventh layers. The third layer... The second transmission lines L2-3, L2-5, L2-7, L2-9, and L2-11 of layers 5, 7, 9, and 11 are connected to the fifth transmission lines (L5-4, L5-6, L5-8, and L5-10) of layers 4, 6, 8, and 10 through the first vias GK1-4, GK1-5, GK1-6, GK1-7, GK1-8, GK1-9, GK1-10, and GK1-11 from layers 4 to 11. Layers 3 and 5... The third transmission lines L3-3, L3-5, L3-7, L3-9, and L3-11 of layers 7, 9, and 11 are connected to the eighth transmission lines L8-4, L8-6, L8-8, and L8-10 of layers 4, 6, 8, and 10 through the fourth vias GK4-4, GK4-5, GK4-6, GK4-7, GK4-8, GK4-9, GK4-10, and GK4-11 from layer 4 to layer 11. Layers 3, 5, and 7... The fourth transmission lines L4-3, L4-5, L4-7, L4-9, and L4-11 of the ninth and eleventh layers are connected to the seventh transmission lines L7-4, L7-6, L7-8, and L7-10 of the fourth, sixth, eighth, and tenth layers through the third vias GK3-4, GK3-5, GK3-6, GK3-7, GK3-8, GK3-9, GK3-10, and GK3-11 from the fourth to the eleventh layers. These together constitute the horizontal-vertical interdigitated capacitor.

[0038] Further preferably, the first transmission lines L1-3, L1-5, L1-7, L1-9, L1-11 of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer are symmetrically parallel to the third transmission lines L3-3, L3-5, L3-7, L3-9, L3-11 of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer; the second transmission lines L2-3, L2-5, L2-7, L2-9, L2-11 of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer are symmetrically parallel to the fourth transmission lines L4-3, L4-5, L4-7, L4-9, L4-11 of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer; the fifth transmission lines L5-4, L5-6, L5-8, L5-10 of the fourth layer, the sixth layer, the eighth layer and the tenth layer are symmetrically parallel to the seventh transmission lines L7-4, L7-6, L7-8, L7-10 of the fourth layer, the sixth layer, the eighth layer and the tenth layer; and the sixth transmission lines L6-4, L6-6, L6-8, L6-10 of the fourth layer, the sixth layer, the eighth layer and the tenth layer are symmetrically parallel to the eighth transmission lines L8-4, L8-6, L8-8, L8-10 of the fourth layer, the sixth layer, the eighth layer and the tenth layer.

[0039] Further, the width and length of the first transmission lines (L1-3, L1-5, L1-7, L1-9, L1-11), the second transmission lines (L2-3, L2-5, L2-7, L2-9, L2-11), the third transmission lines (L3-3, L3-5, L3-7, L3-9, L3-11), the fourth transmission lines (L4-3, L4-5, L4-7, L4-9, L4-11) of the third layer, the fifth layer, the seventh layer, the ninth layer and the eleventh layer, the fifth transmission lines (L5-4, L5-6, L5-8, L5-10), the sixth transmission lines (L6-4, L6-6, L6-8, L6-10), the seventh transmission lines (L7-4, L7-6, L7-8, L7-10), the eighth transmission lines (L8-4, L8-6, L8-8, L8-10) of the fourth layer, the sixth layer, the eighth layer and the tenth layer can be changed to change the capacitance value of the resonant unit, thereby adjusting the center frequency of the filter.

[0040] In combination Figure 7 The twelfth layer inductive layer includes a ninth transmission line L9, a tenth transmission line L10, a first via hole GK1-12 of the twelfth layer, a second via hole GK2-12 of the twelfth layer, a third via hole GK3-12 of the twelfth layer, and a fourth via hole GK4-12 of the twelfth layer.

[0041] The first via hole GK1-12 of the twelfth layer is connected with the second transmission line L2-11 of the eleventh layer at one end and connected with the ninth transmission line L9 of the thirteenth layer at the other end, the second via hole GK2-12 of the twelfth layer is connected with the first transmission line L1-11 of the eleventh layer at one end and connected with the ninth transmission line L9 of the thirteenth layer at the other end, the third via hole GK3-12 of the twelfth layer is connected with the fourth transmission line L4-11 of the eleventh layer at one end and connected with the tenth transmission line L10 of the thirteenth layer at the other end, the fourth via hole GK4-12 of the twelfth layer is connected with the third transmission line L3-11 of the eleventh layer at one end and connected with the tenth transmission line L10 of the thirteenth layer at the other end, and the adjacent coupling parts of the ninth transmission line L9 and the tenth transmission line L10 generate mutual inductance, which realizes space coupling instead of direct coupling.

[0042] Further, the twelfth layer inductance layer includes the ninth transmission line L9 and the tenth transmission line L10 which are parallel and symmetrical, and the inductance value of the resonant unit is changed by changing the width and length, so as to adjust the center frequency of the filter; the mutual inductance value between the resonant units is adjusted by adjusting the length and distance of the coupling part of the ninth transmission line L9 and the tenth transmission line L10, so as to change the size of the passband insertion loss.

[0043] In combination Figure 8 , the thirteenth layer via hole layer includes the first via hole GK1-13 of the thirteenth layer and the third via hole GK3-13 of the thirteenth layer.

[0044] The first via hole GK1-13 of the thirteenth layer is connected with the ninth transmission line L9 of the twelfth layer at one end and connected with the second metal plate C1-2 of the fourteenth layer at the other end through the first via hole GK1-14 of the fourteenth layer, and the third via hole GK3-13 of the thirteenth layer is connected with the tenth transmission line L10 of the twelfth layer at one end and connected with the third metal plate C2-2 of the fourteenth layer at the other end through the third via hole GK3-14 of the fourteenth layer.

[0045] In combination Figure 9 , Figure 10 , the fourteenth and fifteenth layer capacitor layers include the first via hole GK1-14 of the fourteenth layer, the third via hole GK3-14 of the fourteenth layer, the second metal plate C1-2 of the fourteenth layer, the third metal plate C2-2 of the fourteenth layer, the eleventh transmission line I / O Port1 of the fifteenth layer, the twelfth transmission line I / O Port2 of the fifteenth layer, the fourth metal plate C1-1 of the fifteenth layer, and the fifth metal plate C2-1 of the fifteenth layer, and the fourth metal plate C1-1 of the fifteenth layer and the fifth metal plate C2-1 of the fifteenth layer adjacent to each other constitute a planar coupling capacitor, which also realizes space coupling instead of direct source-load coupling.

[0046] Further, the coupling capacitance values of the input and output ports and the source-load end can be changed by changing the length and width of the second metal plate C1-2 and the third metal plate C2-2 of the fourteenth layer and the fourth metal plate C1-1 and the fifth metal plate C2-1 of the fifteenth layer, so as to change the in-band insertion loss and return loss and the position of the transmission zero point.

[0047] In combination Figure 11 , the sixteenth layer encapsulation layer includes the thirteenth transmission line P1, the fourteenth transmission line P2, the fifteenth transmission line P3, and the sixteenth transmission line P4.

[0048] Further, the thirteenth transmission line P1 and the fourteenth transmission line P2 are connected to the eleventh transmission line I / O Port1 and the twelfth transmission line I / O Port2 through the side surface printed metal respectively, and the fifteenth transmission line P3 and the sixteenth transmission line P4 are connected to the first metal plate GND through the side surface printed metal, so as to encapsulate the entire filter.

[0049] In combination Figure 12 , Figure 13 The principle of generating the transmission zero point (Tz) of the new filter topology circuit will be analyzed through the two-port network admittance matrix. The total admittance matrix of the new filter topology circuit is the sum of the admittance matrix of the resonant coupled filter and the feedback capacitance C, so the total admittance matrix is:

[0050]

[0051] Where s=jω, y' 11 , y' 12 , y' 21 , y' 22 are the elements of the admittance matrix of the coupled resonant filter without the feedback capacitance C. Then the transmission zero point can be obtained by solving formula (2):

[0052] -sC+y′ 21 =0#(2)

[0053] Where y' 21 can be obtained by converting the ABCD matrix of the coupled resonant filter without the feedback capacitance C into the admittance matrix Y' after obtaining the ABCD matrix of the coupled resonant filter without the feedback capacitance C.

[0054]

[0055] Where A, B, C parameters represent the following respectively:

[0056]

[0057]

[0058]

[0059] As shown in (2), by graphical method, the functions y1=sC and y2=y' 21 The intersection of these points is the location where the transmission zeros are generated. By adjusting the values ​​of capacitor C and inductor Lg in the new filter topology circuit, the positions of the transmission zeros Tz1, Tz2, Tz3, and Tz4 generated by the new filter topology circuit can be adjusted. Thus, according to the attenuation requirements of a specific frequency band, appropriate theoretical values ​​of capacitor C and inductor Lg can be selected to generate zeros in this specific frequency band. Finally, this guides the design of the actual three-dimensional circuit structure.

[0060] Combination Figure 12 , Figure 14 The novel filtering topology circuit was simulated in the circuit simulation software ADS. Figure 14 The simulation results of this novel filtering topology circuit are shown. Curve S(2,1) is the signal transmission characteristic curve, curve S(1,1) is the signal port reflection characteristic curve, and Tz1, Tz2, Tz3, and Tz4 are the positions of the transmission zeros generated by this novel filtering topology circuit.

[0061] Combination Figure 12 , Figure 15 , Figure 16 The novel filtering topology circuit was simulated in the circuit simulation software ADS. Changing the capacitor C and inductor Lg in the topology circuit will cause the position of the transmission zero point to change.

[0062] Example

[0063] This embodiment uses the electromagnetic simulation software HFSS to simulate and test the miniaturized high-performance LTCC bandpass filter with multiple controllable transmission zeros of the present invention. Figure 17 The results of the simulation calculation of the frequency response characteristics of the filter are shown, where curve S(2,1) is the signal transmission characteristic curve, and curve S(1,1) is the signal port reflection characteristic curve. Figure 17 It can be seen that the center frequency of the LTCC bandpass filter in this embodiment is 1.95GHz, with an in-band insertion loss of less than 1.9dB in the 1.88GHz-2.03GHz range, a minimum insertion loss of only 1.4dB in the passband, an in-band return loss better than 20dB, an attenuation of better than 22dB at 1.5GHz, an attenuation of better than 35dB at 2.4GHz, and an attenuation of better than 55dB at 5.2GHz.

[0064] The application provides a novel filter topology circuit diagram, first, theoretically analyzes, adjusts the position of the transmission zero point by changing the value of the capacitor C and the inductor Lg, thereby determining the value of each ideal component satisfying the high suppression requirement of the specific frequency band in the stop band. Then, a larger capacitor value in a smaller planar area is realized by using the LTCC process and a multi-layer horizontal-vertical interdigital capacitor. Finally, space coupling is used instead of direct coupling, thereby reducing the number of designed components in the actual circuit, further reducing the size of the filter, and improving the integration of the entire filter. The final design size of the filter is 1.6mm*1.56mm*1.04mm, and the filter can be widely applied to various communication networks.

Claims

1. A miniaturized high-performance bandpass filter based on LTCC, characterized in that, It includes, from bottom to top, a first ground layer, a second via layer, third to eleventh capacitor layers, a twelfth inductor layer, a thirteenth via layer, fourteenth and fifteenth capacitor layers, and a sixteenth encapsulation layer; wherein, The first grounding layer includes a first metal plate (GND); The second via layer includes a second via (GK2-2) and a fourth via (GK4-2). One end of the second via (GK2-2) is connected to the first metal plate (GND) of the first layer, and the other end is connected to the first transmission line (L1-3) of the third layer through the second via (GK-2-3) of the third layer. One end of the fourth via (GK4-2) is connected to the first metal plate (GND) of the first layer, and the other end is connected to the third transmission line (L3-3) of the third layer through the fourth via (GK-4-3) of the third layer. The third to eleventh capacitor layers include the first transmission lines (L1-3, L1-5, L1-7, L1-9, L1-11) of the third, fifth, seventh, ninth, and eleventh layers; the second transmission lines (L2-3, L2-5, L2-7, L2-9, L2-11) of the third, fifth, seventh, ninth, and eleventh layers; the third transmission lines (L3-3, L3-5, L3-7, L3-9, L3-11) of the third, fifth, seventh, ninth, and eleventh layers; and the fourth transmission lines (L4-3, L4...) of the third, fifth, seventh, ninth, and eleventh layers. -5, L4-7, L4-9, L4-11), the fifth transmission lines of layers 4, 6, 8 and 10 (L5-4, L5-6, L5-8, L5-10), the sixth transmission lines of layers 4, 6, 8 and 10 (L6-4, L6-6, L6-8, L6-10), the seventh transmission lines of layers 4, 6, 8 and 10 (L7-4, L7-6, L7-8, L7-10), the eighth transmission lines of layers 4, 6, 8 and 10 (L8-4, L8-6, L8-8, L8-10), and the first vias from layers 4 to 11 (G K1-4, GK1-5, GK1-6, GK1-7, GK1-8, GK1-9, GK1-10, GK1-11; the second vias from the third to the eleventh layer (GK2-3, GK2-4, GK2-5, GK2-6, GK2-7, GK2-8, GK2-9, GK2-10, GK2-11); the third vias from the fourth to the eleventh layer (GK3-4, GK3-5, GK3-6, GK3-7, GK3-8, GK3-9, GK3-10, GK3-11); the fourth vias from the third to the eleventh layer (GK4-3, GK4-4). The first transmission lines (L1-3, L1-5, L1-7, L1-9, L1-11) of the third, fifth, seventh, ninth, and eleventh layers are connected to the sixth transmission lines (L6-4, L6-6, L6-8, L6-10) of the fourth, sixth, eighth, and tenth layers through the second vias (GK2-4, GK2-5, GK2-6, GK2-7, GK2-8, GK2-9, GK2-10, GK2-11) from the fourth to the eleventh layers.The second transmission lines (L2-3, L2-5, L2-7, L2-9, L2-11) of layers 3, 5, 7, 9, and 11 are connected to the fifth transmission lines (L5-4, L5-6, L5-8, L5-10) of layers 4, 6, 8, and 10 through the first vias (GK1-4, GK1-5, GK1-6, GK1-7, GK1-8, GK1-9, GK1-10, GK1-11) of layers 4 to 11. The third transmission lines (L3-3, L3-5, L3-7, L3-9, L3-11) of layers 3, 5, 7, 9, and 11 are connected to the eighth transmission lines (L8-4, L8-6, L8-8) of layers 4, 6, 8, and 10. L8-10 is connected via the fourth vias (GK4-4, GK4-5, GK4-6, GK4-7, GK4-8, GK4-9, GK4-10, GK4-11) from layers 4 to 11. The fourth transmission lines (L4-3, L4-5, L4-7, L4-9, L4-11) of layers 3, 5, 7, 9, and 11 are connected to the seventh transmission lines (L7-4, L7-6, L7-8, L7-10) of layers 4, 6, 8, and 10 via the third vias (GK3-4, GK3-5, GK3-6, GK3-7, GK3-8, GK3-9, GK3-10, GK3-11) from layers 4 to 11. These together constitute a horizontal-vertical interdigitated capacitor. The twelfth inductor layer includes a ninth transmission line (L9), a tenth transmission line (L10), a first via (GK1-12), a second via (GK2-12), a third via (GK3-12), and a fourth via (GK4-12). One end of the first via (GK1-12) is connected to the second transmission line (L2-11) of the eleventh layer, and the other end is connected to the ninth transmission line (L9) of the thirteenth layer. One end of the second via (GK2-12) is connected to the first transmission line (L10) of the eleventh layer. 11) One end of the third via (GK3-12) on the 12th layer is connected to the fourth transmission line (L4-11) on the 11th layer, and the other end is connected to the tenth transmission line (L10) on the 13th layer. The fourth via (GK4-12) on the 12th layer is connected to the third transmission line (L3-11) on the 11th layer, and the other end is connected to the tenth transmission line (L10) on the 13th layer. The adjacent coupling parts of the ninth transmission line (L9) and the tenth transmission line (L10) generate mutual inductance. This mutual inductance realizes spatial coupling instead of direct coupling. The thirteenth via layer includes a first via (GK1-13) and a third via (GK3-13) of the thirteenth layer. One end of the first via (GK1-13) of the thirteenth layer is connected to the ninth transmission line (L9) of the twelfth layer, and the other end is connected to the second metal plate (C1-2) of the fourteenth layer through the first via (GK1-14) of the fourteenth layer. One end of the third via (GK3-13) of the thirteenth layer is connected to the tenth transmission line (L10) of the twelfth layer, and the other end is connected to the third metal plate (C2-2) of the fourteenth layer through the third via (GK3-14) of the fourteenth layer. The fourteenth and fifteenth capacitor layers include the first via (GK1-14), the third via (GK3-14), the second metal plate (C1-2), and the third metal plate (C2-2) of the fourteenth layer; the eleventh transmission line (I / O Port1), the twelfth transmission line (I / O Port2), the fourth metal plate (C1-1), and the fifth metal plate (C2-1) of the fifteenth layer. The fourth metal plate (C1-1) and the fifth metal plate (C2-1) of the fifteenth layer are adjacent to each other to form a planar coupling capacitor. This planar coupling capacitor also realizes spatial coupling instead of direct source-load coupling.

2. The miniaturized high-performance bandpass filter based on LTCC according to claim 1, characterized in that, The first transmission lines (L1-3, L1-5, L1-7, L1-9, L1-11) of the third, fifth, seventh, ninth, and eleventh layers are parallel and symmetrical with the third transmission lines (L3-3, L3-5, L3-7, L3-9, L3-11) of the third, fifth, seventh, ninth, and eleventh layers; the second transmission lines (L2-3, L2-5, L2-7, L2-9, L2-11) of the third, fifth, seventh, ninth, and eleventh layers are parallel and symmetrical with the fourth transmission lines (L4-3, L4-5, L4-7, L4-9, L4-11) of the third, fifth, seventh, ninth, and eleventh layers.

3. The miniaturized high-performance bandpass filter based on LTCC according to claim 1, characterized in that, The fifth transmission lines (L5-4, L5-6, L5-8, L5-10) of the fourth, sixth, eighth, and tenth layers are parallel and symmetrical with the seventh transmission lines (L7-4, L7-6, L7-8, L7-10) of the fourth, sixth, eighth, and tenth layers; the sixth transmission lines (L6-4, L6-6, L6-8, L6-10) of the fourth, sixth, eighth, and tenth layers are parallel and symmetrical with the eighth transmission lines (L8-4, L8-6, L8-8, L8-10) of the fourth, sixth, eighth, and tenth layers.

4. The miniaturized high-performance bandpass filter based on LTCC according to claim 1, characterized in that, The twelfth inductor layer includes a ninth transmission line (L9) and a tenth transmission line (L10) that are parallel and symmetrical. By changing their width and length, the inductance value of the resonant unit is changed, thereby adjusting the center frequency of the filter. The mutual inductance value between the resonant units is adjusted by adjusting the length and distance of the coupling part of the ninth transmission line (L9) and the tenth transmission line (L10), which is used to change the magnitude of the insertion loss in the passband.

5. The miniaturized high-performance bandpass filter based on LTCC according to claim 1, 2 or 3, characterized in that, By changing the first transmission line (L1-3, L1-5, L1-7, L1-9, L1-11), the second transmission line (L2-3, L2-5, L2-7, L2-9, L2-11), the third transmission line (L3-3, L3-5, L3-7, L3-9, L3-11), and the fourth transmission line (L4-3, L4-5, L4-7, L4-9, L4-11) of the third, fifth, seventh, ninth, and eleventh layers, the... The width and length of the fifth transmission lines (L5-4, L5-6, L5-8, L5-10), sixth transmission lines (L6-4, L6-6, L6-8, L6-10), seventh transmission lines (L7-4, L7-6, L7-8, L7-10), and eighth transmission lines (L8-4, L8-6, L8-8, L8-10) in layers four, six, eight, and ten are adjusted to change the capacitance value of the resonant unit, thereby adjusting the center frequency of the filter.

6. The miniaturized high-performance bandpass filter based on LTCC according to claim 1, characterized in that, By changing the length and width of the second metal plate (C1-2) and the third metal plate (C2-2) of the fourteenth layer, and the fourth metal plate (C1-1) and the fifth metal plate (C2-1) of the fifteenth layer, the coupling capacitance values ​​of the input and output ports and the coupling capacitance values ​​of the source-load terminals are changed, thereby changing the magnitude of the insertion loss and return loss in the passband and the location of the transmission zero point.

7. The miniaturized high-performance bandpass filter based on LTCC according to claim 1, characterized in that, By changing the radius and length of the second vias (GK2-2, GK2-3, GK2-4, GK2-5, GK2-6, GK2-7, GK2-8, GK2-9, GK2-10, GK2-11) from the second to the eleventh layers, and the fourth vias (GK4-2, GK4-3, GK4-4, GK4-5, GK4-6, GK4-7, GK4-8, GK4-9, GK4-10, GK4-11) from the second to the eleventh layers, the inductance value can be adjusted, thereby adjusting the position of the transmission zero point.

8. The miniaturized high-performance bandpass filter based on LTCC according to claim 1, characterized in that, The sixteenth encapsulation layer includes a thirteenth transmission line (P1), a fourteenth transmission line (P2), a fifteenth transmission line (P3), and a sixteenth transmission line (P4). The thirteenth transmission line (P1) and the fourteenth transmission line (P2) are connected to the eleventh transmission line (I / O Port1) and the twelfth transmission line (I / O Port2) respectively through side-printed metal. The fifteenth transmission line (P3) and the sixteenth transmission line (P4) are connected to the first metal plate (GND) through side-printed metal, thus encapsulating the entire filter.

9. The miniaturized high-performance bandpass filter based on LTCC according to claim 1, characterized in that, The first metal plate (GND), the first via (GK1), the second via (GK2), the third via (GK3), the fourth via (GK4), the first transmission lines (L1-3, L1-5, L1-7, L1-9, L1-11), the second transmission lines (L2-3, L2-5, L2-7, L2-9, L2-11), the third transmission lines (L3-3, L3-5, L3-7, L3-9, L3-11), and the fourth transmission line (L4-3) of the third, fifth, seventh, ninth, and eleventh layers. L4-5, L4-7, L4-9, L4-11), the fifth transmission line (L5-4, L5-6, L5-8, L5-10), the sixth transmission line (L6-4, L6-6, L6-8, L6-10), the seventh transmission line (L7-4, L7-6, L7-8, L7-10), the eighth transmission line (L8-4, L8-6, L8-8, L8-10) of the fourth, sixth, eighth and tenth layers, the second metal plate (C1-2), the third metal plate (C2-2), the eleventh transmission line (I / O Port1), the twelfth transmission line (I / O Port2), the fourth metal plate (C1-1), the fifth metal plate (C2-1), the thirteenth transmission line (P1), the fourteenth transmission line (P2), the fifteenth transmission line (P3), and the sixteenth transmission line (P4) of the tenth layer are all made of silver.

10. A bandpass filtering method, characterized in that, Bandpass filtering is achieved based on the miniaturized high-performance bandpass filter based on LTCC as described in any one of claims 1-9.

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