LTCC-based filter power divider module

Abstract

This invention provides an LTCC-based filtering and power divider module, belonging to the field of radio frequency communication. The module includes an LTCC dielectric substrate and an LC lumped filter and a power divider stacked on the LTCC dielectric substrate. The LTCC dielectric substrate includes a first to a twenty-fourth substrate stacked on top of each other. The LC lumped filter is disposed on the third to fourteenth substrates, and the LC lumped power divider is disposed on the fifteenth to twenty-second substrates. Metal grounds are respectively provided on both sides of the LTCC dielectric substrate, the second substrate, the fourteenth substrate, and the twenty-second substrate. The LC lumped filter and the power divider are cascaded through metal vias. The input port of the LC lumped filter and the output port of the LC lumped power divider are each connected to a metal clamp on the side of the LTCC dielectric substrate. By stacking the filter and the power divider on the dielectric substrate using LTCC technology, and cascading the filter and the power divider through metal vias and isolating them with metal grounds, the integration of the filter and the power divider operating in the L-band is achieved, realizing a miniaturized module design.

Description

Technical Field

[0001] This invention relates to the field of radio frequency communication technology, and in particular to a filtering power divider module based on LTCC. Background Technology

[0002] Currently, the development of 6G technology and satellite internet technology has placed higher demands on the miniaturization of radio frequency devices, with communication frequencies gradually shifting towards higher frequencies such as the Ka, Q, and U bands. These bands have shorter wavelengths, leading to a relative reduction in the size of antenna devices, which requires corresponding transceiver components to be designed more compactly and miniaturized. However, the size of passive components processing low-frequency baseband or intermediate frequency signals in transceiver components is difficult to meet the miniaturization requirements.

[0003] Low Temperature Co-fired Ceramic (LTCC) technology is a process for manufacturing high-frequency electronic circuits and devices, widely used in the manufacture of radio frequency (RF) circuits, microwave circuits, and other electronic components. LTCC technology stacks multiple functional modules (such as signal transmission, filtering, and power distribution) onto a compact substrate by sintering a ceramic substrate and embedded conductive materials at low temperatures (typically below 850°C). This significantly reduces the connection distance between components and the overall board area. Precise process control enables high-density component arrangement, allowing complex circuits to be integrated within a limited space, greatly improving circuit integration and meeting the requirements of miniaturization, high density, low loss, and high performance. For example, Chinese invention patent application CN117525784A, "An LTCC Miniaturized Millimeter-Wave Filter-Power Divider-Balen Module," adopts an improved design that stacks the filter, power divider, and balun, thus solving the problems of difficulty in integrating RF devices and the large overall size of RF devices within the system while ensuring system performance. However, the filters in this module are distributed filters, and the Wilkinson power divider is a distributed power divider. The size of the resonant unit of the distributed filter and power divider is related to the operating frequency. The lower the operating frequency, the larger the size of the resonant unit, which makes it difficult to meet the miniaturization requirements of low-frequency baseband or intermediate frequency signal transceiver components. Summary of the Invention

[0004] The technical problem to be solved by this invention is: how to solve the problem that existing passive devices cannot meet the miniaturization requirements of low-frequency baseband or intermediate-frequency signal transceiver components.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution: a filtering and power divider module based on LTCC, the module including an LTCC dielectric substrate and an LC lumped filter and a power divider stacked on the LTCC dielectric substrate. The LTCC dielectric substrate includes a first to a twenty-fourth substrate stacked on the third to fourteenth substrates, and an LC lumped filter and a LC lumped power divider on the fifteenth to twenty-second substrates. Metal grounds are respectively provided on both sides of the LTCC dielectric substrate, the second substrate, the fourteenth substrate, and the twenty-second substrate. The LC lumped filter and the power divider are cascaded through metal vias. The input port of the LC lumped filter and the output port of the LC lumped power divider are each connected to a metal clamp on the side of the LTCC dielectric substrate.

[0006] Beneficial Effects: This invention utilizes LTCC technology to stack LC lumped filters and power dividers on an LTCC dielectric substrate. The LC lumped filters and power dividers are cascaded through metal vias and isolated by a metal ground, achieving integration of filters and power dividers operating in the L-band. Isolation and matching of the filters and power dividers are completed directly within the module without the need for external isolation and matching circuits. The characteristic of LC lumped filters and power dividers is that by increasing the number of capacitor and inductor layers, the capacitance and inductance values ​​can be changed, thereby determining the operating frequency of the filtering and power divider module. This invention only requires setting the number of capacitor and inductor layers in the LC lumped filters and power dividers to meet the operating frequency of low-frequency baseband or intermediate-frequency signal transceivers, without increasing the size of the filters and power dividers. The internal coupling of the lumped capacitors and inductors forms transmission zeros, eliminating the need for additional structures. This ensures signal transmission as required while achieving a miniaturized design of the filtering and power divider module. Furthermore, the use of metal clamps for power feeding allows for easier embedding of the module into small LTCC transceivers operating in satellite communication bands.

[0007] Preferably, the LC lumped filter includes a first capacitor and a second capacitor disposed between the fifth and tenth substrates, a third capacitor and a fourth capacitor disposed between the seventh and tenth substrates, a fifth capacitor and a sixth capacitor disposed between the ninth and twelfth substrates, a seventh capacitor disposed between the third and sixth substrates, and a first inductor, a second inductor, a third inductor, and a fourth inductor disposed between the eleventh and thirteenth substrates. The first inductor is connected to a metal clamp via a first L-shaped wire, and the second inductor is connected to the input port of the LC lumped power divider via a second L-shaped wire.

[0008] Preferably, the first capacitor includes first to sixth plates arranged in parallel, the second capacitor includes seventh to twelfth plates arranged in parallel, the third capacitor includes thirteenth to sixteenth plates arranged in parallel, and the fourth capacitor includes seventeenth to twentieth plates arranged in parallel. The first and seventh plates are connected to a first ground wire, the third and ninth plates are connected to a second ground wire, the fifth and eleventh plates are connected to a fourth ground wire, the thirteenth and seventeenth plates are connected to a third ground wire, and the fifteenth and nineteenth plates are connected to a fifth ground wire. The first, second, and fourth ground wires are connected to a metal ground on one side of the LTCC dielectric substrate, and the third and fifth ground wires are connected to a metal ground on the other side of the LTCC dielectric substrate. The second, fourth, and sixth plates are connected through a first metal through-hole, the eighth, tenth, and twelfth plates are connected through a second metal through-hole, the fourteenth and sixteenth plates are connected through a third metal through-hole, and the eighteenth and twentieth plates are connected through a fourth metal through-hole.

[0009] The fifth capacitor includes twenty-first to twenty-fourth plates arranged in parallel. The twenty-first and twenty-third plates are connected to the first capacitor through a first metal through-hole, and the twenty-second and twenty-fourth plates are connected to the third capacitor through a third metal through-hole.

[0010] The sixth capacitor includes the twenty-fifth to twenty-eighth plates arranged in parallel. The twenty-fifth and twenty-seventh plates are connected to the second capacitor through the second metal through hole, and the twenty-second and twenty-fourth plates are connected to the fourth capacitor through the fourth metal through hole.

[0011] The seventh capacitor includes the twenty-ninth to thirty-second plates arranged in parallel. The twenty-ninth and thirty-first plates are connected through the fifth metal through hole and then through the third metal through hole to the third capacitor. The thirtieth and thirty-second plates are connected through the sixth metal through hole and then through the fourth metal through hole to the fourth capacitor.

[0012] Preferably, the first inductor includes first to third spirals arranged in parallel, and the second inductor includes fourth to sixth spirals arranged in parallel. The first and fourth spirals are respectively connected to a metal ground on one side of the LTCC dielectric substrate through a sixth ground wire. The third spiral is connected to a first capacitor and a fifth capacitor through a first metal via, and the sixth spiral is connected to a second capacitor and a sixth capacitor through a second metal via. The third spiral is connected to a first L-shaped line as the signal input of the filter, and the sixth spiral is connected to a second L-shaped line as the signal output of the filter.

[0013] The third inductor includes the seventh to ninth spirals arranged in parallel, and the fourth inductor includes the tenth to twelfth spirals arranged in parallel. The seventh and tenth spirals are respectively connected to the metal ground on the other side of the LTCC dielectric substrate through the seventh ground wire. The ninth spiral is connected to the third capacitor and the fifth capacitor through the third metal via. The twelfth spiral is connected to the fourth capacitor and the sixth capacitor through the fourth metal via. The spirals are connected to each other through metal vias.

[0014] Preferably, the LC lumped power divider includes an eighth capacitor disposed between the fifteenth and eighteenth substrates, a ninth capacitor disposed between the nineteenth and twentieth substrates, a fifth inductor and a sixth inductor disposed between the fifteenth and eighteenth substrates, an isolation resistor connected in parallel between the fifth and sixth inductors, the isolation resistor being disposed on the eighteenth substrate, the eighth capacitor being connected to the output port of the LC lumped filter through a seventh metal via, the fifth and sixth inductors being connected to the third L-shaped line and the fourth L-shaped line respectively through a metal via, and the ninth capacitor being connected to two metal clamps on the side of the LTCC dielectric substrate respectively through the third L-shaped line and the fourth L-shaped line as two outputs of the power divider.

[0015] Beneficial Effects: Based on considerations of size control and feasibility, this invention incorporates an isolation resistor in the middle of the spiral lines of the two output inductors of the power divider. Unlike the isolation resistor in traditional Wilkinson power dividers, the length and width of the isolation resistor can be changed according to actual conditions, thereby altering its resistance value. This resistor is embedded within the device, facilitating integration. The resistance value not only affects the isolation degree of the power divider but also its return loss. By setting a reasonable resistance value, impedance matching of the power divider can be achieved more efficiently.

[0016] Preferably, the eighth capacitor includes the thirty-third to thirty-sixth plates arranged in parallel. The thirty-fourth and thirty-sixth plates are respectively connected to the metal ground on the fourteenth substrate through a metal through hole. The thirty-fifth plate is connected to the second L-shaped line through the seventh metal through hole as the signal input port of the power divider. The ninth capacitor includes the thirty-seventh and thirty-eighth plates arranged in parallel. The thirty-seventh plate is connected to a metal clamp through the third L-shaped line as the first output of the power divider. The thirty-eighth plate is connected to another metal clamp through the fourth L-shaped line as the second output of the power divider.

[0017] Preferably, the fifth inductor includes thirteenth to sixteenth parallel spirals, and the sixth inductor includes seventeenth to twentieth parallel spirals. One end of the sixteenth spiral is connected to the third L-shaped wire through the tenth metal through-hole, and one end of the twentieth spiral is connected to the fourth L-shaped wire through the eleventh metal through-hole. The other end of the sixteenth spiral is connected to the other end of the twentieth spiral through an isolation resistor. The thirteenth and seventeenth spirals are directly connected to the thirty-third plate.

[0018] Preferably, a metal groove is formed on the metal ground of the second substrate, and a seventh metal through hole penetrates the metal groove.

[0019] Preferably, the LTCC dielectric substrate has three metal clamps on its side arranged in a U-shape. The three metal clamps are arranged in parallel. The middle metal clamp is connected to the input port of the LC lumped filter as the signal input terminal of the module, and the metal clamps on both sides are connected to the two output ports of the LC lumped power divider as the signal output terminals of the module.

[0020] Preferably, the material of the first to twenty-fourth substrates is Ferro-A6M, with a relative permittivity of 5.9 and a loss tangent of 0.0015.

[0021] The advantages provided by this invention are:

[0022] 1. The LTCC-based filtering power divider module of this invention can be widely used in the processing unit of intermediate frequency signals or baseband signals in satellite communication systems. At the same time, it has universality in the 1-1.3GHz frequency band and can support the radio frequency front-end requirements of L-band GPS navigation, radar systems and other wireless communication devices.

[0023] 2. This invention employs a cascaded design approach, integrating filters and power dividers to construct a filtering and power dividing module. Modular design achieves isolation and impedance matching between components, significantly reducing dependence on external matching networks. Simultaneously, the optimized layout using a multi-layer stacked structure effectively improves the integration of RF equipment, reduces overall insertion loss, and provides a key technological path for the miniaturization of RF front-end systems.

[0024] Based on low-temperature co-fired ceramic (LTC) technology, this invention achieves three-dimensional integration of multi-layer circuits within a single substrate, successfully integrating passive components such as power dividers and filters into a single package. The LTC substrate exhibits excellent thermal stability and mechanical strength, making it particularly suitable for RF applications in harsh environments. Compared to traditional PCB processes, LTC technology demonstrates significant miniaturization advantages, enabling high-density interconnects and miniaturized packaging. Attached Figure Description

[0025] Figure 1 A perspective view of a LTCC-based filtering power divider module provided in an embodiment of the present invention;

[0026] Figure 2 A perspective view of an LTCC-based filtering power divider module provided in an embodiment of the present invention;

[0027] Figure 3 A top view of an LTCC-based filtering power divider module provided in an embodiment of the present invention;

[0028] Figure 4 A side view of an LTCC-based filtering power divider module provided in an embodiment of the present invention;

[0029] Figure 5 A side view from another perspective of the LTCC-based filtering power divider module provided in an embodiment of the present invention;

[0030] Figure 6 A schematic diagram of the filter in the LTCC-based filtering power divider module provided in an embodiment of the present invention;

[0031] Figure 7 A top view of the filter in the LTCC-based filtering power divider module provided in an embodiment of the present invention;

[0032] Figure 8 A schematic diagram of the power divider in the LTCC-based filtering power divider module provided in an embodiment of the present invention;

[0033] Figure 9 A top view of the power divider in the LTCC-based filtering power divider module provided in an embodiment of the present invention;

[0034] Figure 10 The simulation results of return loss and insertion loss of the LTCC-based filtering power divider module provided in the embodiments of the present invention are shown in the figure.

[0035] Figure 11 The simulation results of the voltage standing wave ratio of the LTCC-based power divider module provided in this embodiment of the invention are shown in the figure.

[0036] Figure 12 The simulation results of the isolation of the LTCC-based filtering power divider module are shown in the embodiment of the present invention.

[0037] Figure 13 The simulation results of the port amplitude difference of the LTCC-based filtering power divider module provided in the embodiments of the present invention are shown in the figure.

[0038] In the diagram: 1 First metal clamp, 2 Second metal clamp, 3 Third metal clamp, 4 First metal ground, 5 Second metal ground, 6 Third metal ground, 7 Fourth metal ground, 8 Fifth metal ground, 9 First grounding wire, 10 Second grounding wire, 11 Third grounding wire, 12 Fourth grounding wire, 13 Fifth grounding wire, 14 Sixth grounding wire, 15 Seventh grounding wire, 16 First electrode plate, 17 Second electrode plate, 18 Third electrode plate, 19 Fourth electrode plate, 20 Fifth electrode plate, 21 Sixth electrode plate, 22 Seventh electrode plate, 23 24. Eighth plate, 25. Ninth plate, 26. Tenth plate, 27. Eleventh plate, 28. Twelfth plate, 29. Twentieth plate, 30. Thirty-first plate, 31. Thirty-second plate, 32. First metal through-hole, 33. Second metal through-hole, 34. Seventh metal through-hole, 35. First spiral, 36. Second spiral, 37. Third spiral, 38. Fourth spiral, 39. Fifth spiral, 40. Sixth spiral, 41. Thirteenth spiral, 42. Fourteenth spiral, 43. Fifteenth spiral Spiral, 44 Sixteenth Spiral, 45 Eighth Metal Through-hole, 46 Thirty-seventh Plate, 47 Thirty-eighth Plate, 48 Ninth Metal Through-hole, 49 Thirteenth Plate, 50 Fourteenth Plate, 51 Fifteenth Plate, 52 Sixteenth Plate, 53 Seventeenth Plate, 54 Eighteenth Plate, 55 Nineteenth Plate, 56 Twentieth Plate, 57 Third Metal Through-hole, 58 Fourth Metal Through-hole, 59 Seventeenth Spiral, 60 Eighteenth Spiral, 61 Nineteenth Spiral, 62 Twentieth Spiral, 6 3 First capacitor, 64 Second capacitor, 65 Third capacitor, 66 Fourth capacitor, 67 Fifth capacitor, 68 Sixth capacitor, 69 Seventh capacitor, 70 First inductor, 71 Second inductor, 72 Third inductor, 73 Fourth inductor, 74 First L-shaped line, 75 Second L-shaped line, 76 Eighth capacitor, 77 Ninth capacitor, 78 Fifth inductor, 79 Sixth inductor, 80 Isolation resistor, 81 Metal slot, 82 Tenth metal through hole, 83 Eleventh metal through hole, 84 Third L-shaped line, 85 Fourth L-shaped line. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] See Figures 1 to 3This embodiment provides a LTCC-based filtering and power divider module, including an LTCC dielectric substrate and an LC lumped filter and a power divider stacked on the LTCC dielectric substrate. The LTCC dielectric substrate includes a first to a twenty-fourth substrate stacked sequentially from bottom to top. The LC lumped filter is disposed on the third to fourteenth substrates, and the LC lumped power divider is disposed on the fifteenth to twenty-second substrates. Metal grounds are respectively provided on both sides of the LTCC dielectric substrate, the second substrate, the fourteenth substrate, and the twenty-second substrate. The LC lumped filter and the power divider are cascaded through metal vias. The input port of the LC lumped filter and the output port of the LC lumped power divider are each connected to a metal clamp on the side of the LTCC dielectric substrate.

[0041] For ease of description, Figure 4 The side view shown is called the left side of the overall module. Figure 5 The side view shown is called the right side of the overall module. The metal grounds on the left side of the LTCC dielectric substrate, the right side of the LTCC dielectric substrate, the second substrate, the fourteenth substrate, and the twenty-second substrate are respectively called the first metal ground 4, the second metal ground 5, the third metal ground 6, the fourth metal ground 7, and the fifth metal ground 8. The LC lumped filter is located between the third metal ground 6 and the fourth metal ground 7, that is, in the lower region of the LTCC dielectric substrate. The LC lumped power divider is located between the fourth metal ground 7 and the fifth metal ground 8, that is, in the upper region of the LTCC dielectric substrate. A metal isolation ground is provided between the filter and the power divider to isolate the devices.

[0042] It should be noted that the input port of the LC lumped filter and the output port of the LC lumped power divider are each connected to a metal clamp on the side of the LTCC dielectric substrate. This means that the number of metal clamps is determined by the number of input ports of the filter and the number of output ports of the power divider. In the LTCC-based filtering and power dividing module of this invention, the LC lumped filter has one input port and the LC lumped power divider has two output ports. Therefore, three metal clamps are provided on the side of the LTCC dielectric substrate. For ease of description, see [link to documentation]. Figure 2 The three metal clamps are designated as first metal clamp 1, second metal clamp 2, and third metal clamp 3. First metal clamp 1 is connected to the input port of the LC lumped filter, second metal clamp 2 is connected to one output port of the LC lumped power divider, and third metal clamp 3 is connected to the other output port of the LC lumped power divider. The entire module completes input and output through the three metal clamps set on one side.

[0043] This invention utilizes LTCC technology to stack LC lumped filters and power dividers on an LTCC dielectric substrate. The LC lumped filters and power dividers are cascaded through metal vias and isolated by a metal ground, achieving integration of filters and power dividers operating in the L-band. Isolation and matching of the filters and power dividers are completed directly within the module without the need for external isolation and matching circuits. The characteristic of LC lumped filters and power dividers is that by increasing the number of capacitor and inductor layers, the capacitance and inductance values ​​can be changed, thereby determining the operating frequency of the filtering and power divider module. This invention only requires setting the number of capacitor and inductor layers in the LC lumped filters and power dividers to meet the operating frequency requirements of low-frequency baseband or intermediate-frequency signal transceivers, without increasing the size of the filters and power dividers. The internal coupling of the lumped capacitors and inductors forms transmission zeros, eliminating the need for additional structures. This ensures signal transmission as required while achieving a miniaturized design of the filtering and power divider module. Furthermore, the use of metal clamps for power feeding allows for easier embedding of the module into small LTCC transceivers operating in satellite communication bands. Compared to traditional filter and power divider integrated modules, this invention has the advantages of high integration, small size, and high isolation, which is in line with the future trend of high integration and miniaturization of circuits.

[0044] The LTCC-based filtering power divider module of this invention can be widely used in the processing unit of intermediate frequency or baseband signals in satellite communication systems. It is also versatile in the 1-1.3GHz frequency band and can support the RF front-end requirements of L-band GPS navigation, radar systems and other wireless communication devices.

[0045] See Figure 6 The LC lumped filter includes seven VIC capacitors and four spiral inductors. The VIC capacitors and spiral inductors are cascaded through metal vias and striplines for filtering the input signal. The seven VIC capacitors include a first capacitor 63 and a second capacitor 64 located between the fifth and tenth substrates; a third capacitor 65 and a fourth capacitor 66 located between the seventh and tenth substrates; a fifth capacitor 67 and a sixth capacitor 68 located between the ninth and twelfth substrates; and a seventh capacitor 69 located between the third and sixth substrates. The four spiral inductors include a first inductor 70, a second inductor 71, a third inductor 72, and a fourth inductor 73 located between the eleventh and thirteenth substrates. The first inductor 70 is connected to a first metal clamp 1 via a first L-shaped wire 74, and the second inductor 71 is connected to the input port of the LC lumped power divider via a second L-shaped wire 75. The first L-shaped wire 74 serves as the signal input terminal of the filter, and the second L-shaped wire 75 serves as the signal output terminal of the filter.

[0046] See Figure 4 and Figure 5The first capacitor 63 and the second capacitor 64 are each composed of six layers of plates stacked together, with each plate measuring 0.97mm × 1.6mm; the third capacitor 65 and the fourth capacitor 66 are each composed of four layers of plates stacked together, with each plate measuring 1.1mm × 1.5mm; the fifth capacitor 67 and the sixth capacitor 68 are each composed of four layers of plates stacked together, with each plate measuring 1.1mm × 1.02mm; and the seventh capacitor 69 is composed of four layers of plates stacked together, with each plate measuring 0.9mm × 0.8mm.

[0047] The first capacitor 63 includes a first electrode plate 16, a second electrode plate 17, a third electrode plate 18, a fourth electrode plate 19, a fifth electrode plate 20, and a sixth electrode plate 21 arranged in parallel; the second capacitor 64 includes a seventh electrode plate 22, an eighth electrode plate 23, a ninth electrode plate 24, a tenth electrode plate 25, an eleventh electrode plate 26, and a twelfth electrode plate 27 arranged in parallel; the third capacitor 65 includes a thirteenth electrode plate 49, a fourteenth electrode plate 50, a fifteenth electrode plate 51, and a sixteenth electrode plate 52 arranged in parallel; and the fourth capacitor 66 includes a seventeenth electrode plate 53, an eighteenth electrode plate 54, a nineteenth electrode plate 55, and a twentieth electrode plate 56 arranged in parallel.

[0048] The first electrode plate 16 and the seventh electrode plate 22 are connected to the first ground wire 9; the third electrode plate 18 and the ninth electrode plate 24 are connected to the second ground wire 10; the fifth electrode plate 20 and the eleventh electrode plate 26 are connected to the fourth ground wire 12; the thirteenth electrode plate 49 and the seventeenth electrode plate 53 are connected to the third ground wire 11; the fifteenth electrode plate 51 and the nineteenth electrode plate 55 are connected to the fifth ground wire 13; the first ground wire 9, the second ground wire 10, and the fourth ground wire 12 are connected to the first metal ground 4 on one side of the LTCC dielectric substrate; the third ground wire 11 and the fifth ground wire 13 are connected to the second metal ground 5 on the other side of the LTCC dielectric substrate; the second electrode plate 17, the fourth electrode plate 19, and the sixth electrode plate 21 are connected through the first metal through hole 32; the eighth electrode plate 23, the tenth electrode plate 25, and the twelfth electrode plate 27 are connected through the second metal through hole 33; the fourteenth electrode plate 50 and the sixteenth electrode plate 52 are connected through the third metal through hole 57; and the eighteenth electrode plate 54 and the twentieth electrode plate 56 are connected through the fourth metal through hole 58.

[0049] The fifth capacitor 67 includes a 21st, 22nd, 23rd, and 24th plate (not shown in the figure) arranged in parallel. The 21st and 23rd plates are connected to the first capacitor 63 through the first metal through hole 32, and the 22nd and 24th plates are connected to the third capacitor 65 through the third metal through hole 57.

[0050] The sixth capacitor 68 includes a 25th, 26th, 27th, and 28th electrode plate (not shown in the figure) arranged in parallel. The 25th and 27th electrode plates are connected to the second capacitor 64 through the second metal through hole 33, and the 22nd and 24th electrode plates are connected to the fourth capacitor 66 through the fourth metal through hole 58.

[0051] The seventh capacitor 69 includes a twenty-ninth plate 28, a thirtieth plate 29, a thirty-first plate 30, and a thirty-second plate 31 arranged in parallel. The twenty-ninth plate 28 and the thirty-first plate 30 are connected through a fifth metal through hole (not shown in the figure) and then connected to the third capacitor 65 through a third metal through hole 57. The thirtieth plate 29 and the thirty-second plate 31 are connected through a sixth metal through hole (not shown in the figure) and then connected to the fourth capacitor 66 through a fourth metal through hole 58.

[0052] See Figure 4 and Figure 5 The first inductor 70, the second inductor 71, the third inductor 72, and the fourth inductor 73 are all spiral inductors, each composed of multiple stacked spirals. Increasing the number of stacked layers increases the inductance value without increasing the inductor size. For example... Figure 7 As shown, the inductance of the spiral inductor is mainly determined by the lateral length L1 and the longitudinal length L2. Specifically, the first inductor 70 and the second inductor 71 are composed of three layers of stacked spirals, with a lateral length L1 of 1.2 mm and a longitudinal length L2 of 0.85 mm; the third inductor 72 and the fourth inductor 73 are also composed of three layers of stacked spirals, with a lateral length L1 of 1 mm and a longitudinal length L2 of 0.86 mm.

[0053] The first inductor 70 includes a first spiral 35, a second spiral 36, and a third spiral 37 arranged in parallel. The second inductor 71 includes a fourth spiral 38, a fifth spiral 39, and a sixth spiral 40 arranged in parallel. The first spiral 35 and the fourth spiral 38 are respectively connected to the first metal ground 4 on one side of the LTCC dielectric substrate through the sixth ground wire 14. The third spiral 37 is connected to the first capacitor 63 and the fifth capacitor 67 through the first metal through-hole 32. The sixth spiral 40 is connected to the second capacitor 64 and the sixth capacitor 68 through the second metal through-hole 33. The third spiral 37 is connected to the first L-shaped line 74 as the signal input of the filter, and the sixth spiral 40 is connected to the second L-shaped line 75 as the signal output of the filter.

[0054] The third inductor 72 includes a seventh spiral, an eighth spiral, and a ninth spiral (not shown in the figure) arranged in parallel. The fourth inductor 73 includes a tenth spiral, an eleventh spiral, and a twelfth spiral (not shown in the figure) arranged in parallel. The seventh and tenth spirals are respectively connected to the second metal ground 5 on the other side of the LTCC dielectric substrate through the seventh ground wire 15. The ninth spiral is connected to the third capacitor 65 and the fifth capacitor 67 through the third metal through-hole 57. The twelfth spiral is connected to the fourth capacitor 66 and the sixth capacitor 68 through the fourth metal through-hole 58. The spirals are connected to each other through metal through-holes.

[0055] See Figure 8 and Figure 9 The LC lumped power divider includes two VIC capacitors, two spiral inductors, and an isolation resistor. The VIC capacitors and spiral inductors are cascaded through metal vias and striplines to distribute power to the filter's output signal. The VIC capacitors consist of multiple parallel stacked metal plates. Specifically, the eighth capacitor 76 consists of four stacked plates, each measuring 1mm × 0.8mm; the ninth capacitor 77 consists of two stacked plates, each measuring 0.7mm × 1.5mm. The spiral inductors consist of multiple stacked spirals. Specifically, the fifth inductor 78 and the sixth inductor 79 consist of four stacked spirals, with a lateral length L1 of 1.7mm and a longitudinal length L2 of 1.8mm.

[0056] The system includes two VIC-type capacitors: an eighth capacitor 76 located between the fifteenth and eighteenth substrates, and a ninth capacitor 77 located between the nineteenth and twentieth substrates. Two spiral inductors include a fifth inductor 78 and a sixth inductor 79 located between the fifteenth and eighteenth substrates. An isolation resistor 80 is connected in parallel between the fifth inductor 78 and the sixth inductor 79, and the isolation resistor 80 is located on the eighteenth substrate. The eighth capacitor 76 is connected to the output port of the LC lumped filter through a seventh metal via 34. The fifth inductor 78 and the sixth inductor 79 are connected to the third L-shaped line 84 and the fourth L-shaped line 85, respectively, through a metal via. The ninth capacitor 77 is connected to two metal clamps on the side of the LTCC dielectric substrate via the third L-shaped line 84 and the fourth L-shaped line 85, serving as two outputs of the power divider. The ninth capacitor 77 is connected to the second metal clamp 2 on the side of the LTCC dielectric substrate via the third L-shaped line 84, serving as one output of the power divider. The ninth capacitor 77 is connected to the third metal clamp 3 on the side of the LTCC dielectric substrate via the fourth L-shaped line 85, serving as the other output of the power divider. The isolation resistor is not connected in parallel to the output port of the power divider as in a traditional Wilkinson power divider, but is connected in parallel to the middle spiral of the fifth and sixth inductors.

[0057] See also Figure 4 and Figure 5The eighth capacitor 76 includes three parallel plates: the 33rd, 34th, 35th, and 36th (not shown in the figure). The 34th and 36th plates are connected to the fourth metal ground 7 on the 14th substrate through a metal through-hole. The 35th plate is connected to the second L-shaped line 75 through the seventh metal through-hole 34 as the signal input port of the power divider. The ninth capacitor 77 includes two parallel plates: the 37th plate 46 and the 38th plate 47. The 37th plate 46 is connected to the second metal clamp 2 through the third L-shaped line 84 as the first output of the power divider. The 38th plate 47 is connected to the third metal clamp 3 through the fourth L-shaped line 85 as the second output of the power divider.

[0058] The fifth inductor 78 includes a thirteenth spiral 41, a fourteenth spiral 42, a fifteenth spiral 43, and a sixteenth spiral 44 arranged in parallel. The sixth inductor 79 includes a seventeenth spiral 59, an eighteenth spiral 60, a nineteenth spiral 61, and a twentieth spiral 62 arranged in parallel. One end of the sixteenth spiral 44 is connected to the third L-shaped line 84 through the tenth metal through-hole 82. One end of the twentieth spiral 62 is connected to the fourth L-shaped line 85 through the eleventh metal through-hole 83. The other end of the sixteenth spiral 44 and the other end of the twentieth spiral 62 are connected through an isolation resistor 80. The thirteenth spiral 41 and the seventeenth spiral 59 are directly connected to the thirty-third plate.

[0059] Based on considerations of size control and feasibility, an isolation resistor 80 is placed in the middle of the spiral lines of the two output inductors (inductor 78, inductor 79) of the power divider. Unlike the isolation resistors in traditional Wilkinson power dividers, this isolation resistor has a resistance of 50 ohms. A 100-ohm sheet resistance resistive paste (FX 87-101) is used for the isolation resistor, with dimensions of 0.3mm × 0.6mm, achieving a 50-ohm resistance. The length and width of the isolation resistor can be changed according to actual needs, thus altering the resistance value. This resistor is embedded inside the device, facilitating integration. The resistance value of the isolation resistor not only affects the isolation degree of the power divider but also its return loss. By setting a reasonable resistance value, impedance matching of the power divider can be achieved more efficiently.

[0060] This invention equates the traditional microstrip Wilkinson power divider to an LC lumped power divider, and simultaneously achieves the module's isolation and matching requirements by adding a 50-ohm isolation resistor at a specific location. Compared with a distributed power divider at the same operating frequency, the size of the power divider is greatly reduced.

[0061] See Figure 8A metal groove 81 is formed on the fourth metal ground 7 on the second substrate, and a seventh metal through hole 34 penetrates the metal groove 81. The radius of the seventh metal through hole 34 is 0.025 mm, the radius of the metal groove 81 is 0.05 mm, and the thickness of each metal ground layer is 0.01 mm.

[0062] See Figure 1 The first metal clamp 1, the second metal clamp 2, and the third metal clamp 3 on the side of the LTCC dielectric substrate are all U-shaped and arranged in parallel. The first metal clamp 1 in the middle is connected to the input port of the LC lumped filter as the signal input terminal of the module. The second metal clamp 2 and the third metal clamp 3 on both sides are respectively connected to the two output ports of the LC lumped power divider as the signal output terminals of the module. Specifically, the first metal clamp 1 is connected to the first L-shaped line 74, the second metal clamp 2 is connected to the third L-shaped line 84, and the third metal clamp 3 is connected to the fourth L-shaped line 85. The first metal clamp 1 is used for external signal input to the filter, and the second metal clamp 2 and the third metal clamp 3 are used to output the two signals output by the power divider to the outside.

[0063] The first to twenty-fourth substrates are made of Ferro-A6M material with a relative permittivity of 5.9 and a loss tangent of 0.0015. Each substrate is 0.096 mm thick and is manufactured using a low-temperature co-fired ceramic process. All metal materials used are silver. A first ground wire 9 is provided on the fifth substrate, a second ground wire 10 and a third ground wire 11 are provided on the seventh substrate, a fourth ground wire 12 and a fifth ground wire 13 are provided on the ninth substrate, and a sixth ground wire 14 and a seventh ground wire 15 are provided on the eleventh substrate.

[0064] The LTCC-based filtering power divider module of this invention measures 4.2 mm × 4 mm × 2.304 mm. Performance tests were conducted on the module. For example... Figure 10 The simulation results of the filtering power divider module are shown in the figure. The insertion loss within the passband of the entire filtering power divider module is less than 5.8 dB, and the return loss within the passband is less than -15.76 dB. Transmission zeros are formed at 600 MHz and 650 MHz respectively through electromagnetic coupling between lumped elements. Figure 11 As shown, the voltage standing wave ratio (VSWR) within the passband is less than 1.4. Figure 12 , Figure 13 The passband isolation is less than -16.75dB, and the maximum amplitude difference at the output ports is 0.3dB.

[0065] Working principle: The signal enters the filter through the first L-shaped line 74 via the first metal clamp 1, passes through the parallel resonant unit composed of the first capacitor 63 and the first inductor 70, and is then input to the fifth capacitor 67. After passing through the parallel resonant unit composed of the third capacitor 65 and the third inductor 72, it is input to the seventh capacitor 69. After passing through the parallel resonant unit composed of the fourth capacitor 66 and the fourth inductor 73, it is input to the sixth capacitor 68. Finally, after passing through the parallel resonant unit composed of the second capacitor 64 and the second inductor 71, the filtered signal is output from the second L-shaped line 75.

[0066] The filtered signal is input to the power divider through the seventh metal through-hole 34. The signal first passes through the eighth capacitor 76, and then is split into two signals by the fifth inductor 78 and the sixth inductor 79. These signals are then output to the second metal clamp 2 and the third metal clamp 3 through the third L-shaped line 84 and the fourth L-shaped line 85, respectively. The ninth capacitor 77 is connected in parallel to the two output ports of the power divider through the tenth metal through-hole 82 and the eleventh metal through-hole 83, respectively.

[0067] This invention employs a cascaded design approach, integrating filters and power dividers to construct a filtering and power dividing module. Modular design achieves isolation and impedance matching between components, significantly reducing reliance on external matching networks. Simultaneously, the optimized layout using a multi-layer stacked structure effectively improves the integration of RF equipment, reduces overall insertion loss, and provides a key technological path for the miniaturization of RF front-end systems.

[0068] Based on low-temperature co-fired ceramic (LTC) technology, this invention achieves three-dimensional integration of multi-layer circuits within a single substrate, successfully integrating passive devices such as power dividers and filters into a single package. The LTC substrate exhibits excellent thermal stability and mechanical strength, making it particularly suitable for RF applications in harsh environments. Compared to traditional PCB processes, LTC technology demonstrates significant miniaturization advantages, enabling high-density interconnects and miniaturized packaging. Furthermore, powered by metal clamps, this module can be flexibly applied to standalone devices or RF transceiver assemblies, offering excellent system compatibility and scalability.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A filter power divider module based on LTCC, characterized in that: The module includes an LTCC dielectric substrate and an LC lumped filter and an LC lumped power divider stacked on the LTCC dielectric substrate. The LTCC dielectric substrate includes a first to a twenty-fourth substrate stacked on top of each other. The LC lumped filter is disposed on the third to fourteenth substrates, and the LC lumped power divider is disposed on the fifteenth to twenty-second substrates. Metal ground planes are provided on both sides of the LTCC dielectric substrate, the second substrate, the fourteenth substrate, and the twenty-second substrate. The LC lumped filter and the LC lumped power divider are cascaded through metal vias. The input port of the LC lumped filter and the output port of the LC lumped power divider are each connected to a metal clamp on the side of the LTCC dielectric substrate. The LC lumped filter includes a VIC capacitor and a spiral inductor. The VIC capacitor includes a first and a second capacitor disposed between the fifth and tenth substrates, a third and a fourth capacitor disposed between the seventh and tenth substrates, a fifth and a sixth capacitor disposed between the ninth and twelfth substrates, and a seventh capacitor disposed between the third and sixth substrates. The spiral inductor includes... The first, second, third, and fourth inductors are located between the eleventh and thirteenth substrates. The first inductor is connected to a metal clamp via a first L-shaped line, and the second inductor is connected to the input port of the LC lumped power divider via a second L-shaped line, which serves as the output port of the LC lumped filter. The LC lumped power divider includes a VIC capacitor and a spiral inductor. The VIC capacitor includes an eighth capacitor located between the fifteenth and eighteenth substrates and a ninth capacitor located between the nineteenth and twentieth substrates. The spiral inductor includes a fifth inductor and a sixth inductor located between the fifteenth and eighteenth substrates. An isolation resistor is connected in parallel between the fifth and sixth inductors and is located on the eighteenth substrate. The eighth capacitor is connected to the output port of the LC lumped filter via a seventh metal via. The fifth and sixth inductors are connected to the third and fourth L-shaped lines via metal vias, respectively. The ninth capacitor is connected to two metal clamps on the side of the LTCC dielectric substrate via the third and fourth L-shaped lines, respectively, serving as two outputs of the LC lumped power divider.

2. The LTCC-based filtering power divider module according to claim 1, characterized in that: The first capacitor (63) includes the first to sixth plates arranged in parallel, the second capacitor (64) includes the seventh to twelfth plates arranged in parallel, the third capacitor (65) includes the thirteenth to sixteenth plates arranged in parallel, and the fourth capacitor (66) includes the seventeenth to twentieth plates arranged in parallel. The first and seventh plates are connected to the first ground wire, the third and ninth plates are connected to the second ground wire, the fifth and eleventh plates are connected to the fourth ground wire, the thirteenth and seventeenth plates are connected to the third ground wire, the fifteenth and nineteenth plates are connected to the fifth ground wire, the first, second, and fourth ground wires are connected to the metal ground on one side of the LTCC dielectric substrate, and the third and fifth ground wires are connected to the metal ground on the other side of the LTCC dielectric substrate. The second, fourth, and sixth plates are connected through the first metal through-hole, the eighth, tenth, and twelfth plates are connected through the second metal through-hole, the fourteenth and sixteenth plates are connected through the third metal through-hole, and the eighteenth and twentieth plates are connected through the fourth metal through-hole. The fifth capacitor (67) includes the twenty-first to twenty-fourth plates arranged in parallel. The twenty-first and twenty-third plates are connected to the first capacitor through the first metal through hole, and the twenty-second and twenty-fourth plates are connected to the third capacitor through the third metal through hole. The sixth capacitor (68) includes the twenty-fifth to twenty-eighth plates arranged in parallel. The twenty-fifth and twenty-seventh plates are connected to the second capacitor (64) through the second metal through hole, and the twenty-second and twenty-fourth plates are connected to the fourth capacitor (66) through the fourth metal through hole. The seventh capacitor (69) includes the twenty-ninth to thirty-second plates arranged in parallel. The twenty-ninth and thirty-first plates are connected through the fifth metal through hole and then through the third metal through hole to the third capacitor (65). The thirtieth and thirty-second plates are connected through the sixth metal through hole and then through the fourth metal through hole to the fourth capacitor (66).

3. The LTCC-based filtering power divider module according to claim 2, characterized in that: The first inductor (70) includes first to third spirals arranged in parallel, and the second inductor (71) includes fourth to sixth spirals arranged in parallel. The first and fourth spirals are respectively connected to the metal ground on one side of the LTCC dielectric substrate through the sixth ground wire. The third spiral is connected to the first and fifth capacitors through the first metal via, and the sixth spiral is connected to the second and sixth capacitors through the second metal via. The third spiral is connected to the first L-shaped line as the signal input of the filter, and the sixth spiral is connected to the second L-shaped line as the signal output of the filter. The third inductor (72) includes the seventh to ninth spirals arranged in parallel, and the fourth inductor (73) includes the tenth to twelfth spirals arranged in parallel. The seventh and tenth spirals are respectively connected to the metal ground on the other side of the LTCC dielectric substrate through the seventh ground wire. The ninth spiral is connected to the third capacitor and the fifth capacitor through the third metal via. The twelfth spiral is connected to the fourth capacitor and the sixth capacitor through the fourth metal via. The spirals are connected to each other through metal vias.

4. The LTCC-based filtering power divider module according to claim 1, characterized in that: The eighth capacitor (76) includes the thirty-third to thirty-sixth plates arranged in parallel. The thirty-fourth and thirty-sixth plates are respectively connected to the metal ground on the fourteenth substrate through a metal through hole. The thirty-fifth plate is connected to the second L-shaped line (75) through the seventh metal through hole (34) as the signal input port of the power divider. The ninth capacitor (77) includes the thirty-seventh and thirty-eighth plates arranged in parallel. The thirty-seventh plate is connected to a metal clamp through the third L-shaped line as the first output of the power divider. The thirty-eighth plate is connected to another metal clamp through the fourth L-shaped line as the second output of the power divider.

5. The LTCC-based filtering power divider module according to claim 4, characterized in that: The fifth inductor (78) includes the thirteenth to sixteenth spirals arranged in parallel, and the sixth inductor (79) includes the seventeenth to twentieth spirals arranged in parallel. One end of the sixteenth spiral is connected to the third L-shaped line (84) through the tenth metal through hole (82), and one end of the twentieth spiral is connected to the fourth L-shaped line (85) through the eleventh metal through hole (83). The other end of the sixteenth spiral is connected to the other end of the twentieth spiral through an isolation resistor (80). The thirteenth spiral and the seventeenth spiral are directly connected to the thirty-third plate.

6. The LTCC-based filtering power divider module according to claim 1, characterized in that: A metal groove is formed on the metal ground of the second substrate, and a seventh metal through hole penetrates the metal groove.

7. The LTCC-based filtering power divider module according to claim 1, characterized in that: The LTCC dielectric substrate has three metal clamps on its side arranged in a U-shape. The three metal clamps are arranged in parallel. The middle metal clamp is connected to the input port of the LC lumped filter as the signal input terminal of the module, and the metal clamps on both sides are connected to the two output ports of the LC lumped power divider as the signal output terminals of the module.

8. The LTCC-based filtering power divider module according to claim 1, characterized in that: The first to twenty-fourth substrates are made of Ferro-A6M, with a relative permittivity of 5.9 and a loss tangent of 0.0015.

9. The LTCC-based filtering power divider module according to claim 1, characterized in that: The isolation resistor has a resistance of 50 ohms.

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