Universal miniaturized filter bank

Abstract

The invention belongs to the technical field of radar and electronic equipment, and discloses a universal miniaturized filter bank. The miniaturized filter bank comprises a multilayer ceramic substrate, a filter, a switch, a capacitor and a circuit interconnection wire. According to the invention, not only are the types and the number of component-level components greatly reduced, but also the problems of electromagnetic noise and signal interference caused by nonlinearity of the components are reduced through airtight packaging, and the electromagnetic compatibility characteristic of the system is improved.

Description

Technical Field

[0001] The invention mainly relates to the technical field of radar and electronic equipment, and in particular to a universal miniaturized filter group. Background Art

[0002] In all types of electronic devices, the RF filter group in the frequency conversion circuit is an indispensable circuit, which determines the spurious index of the receiving and transmitting signals. In some devices with high requirements for the performance of the transmitting signal, two or more RF filter groups are also required. In addition, with the current development of miniaturization of microsystems, due to the consideration of product versatility and design flexibility, it is not convenient to include the pre-selected filter group in the design of RF integrated circuits RFIC and system-on-chip SOC. In addition, the filter is large in size, which has a great impact on the layout and wiring of the printed circuit board PCB. Therefore, the integration of filters, especially switch filter groups, is imminent and is an important condition for breaking through the bottleneck of miniaturization of transceiver channels. Summary of the invention

[0003] The purpose of the present invention is to provide a universal miniaturized filter group to realize the segmented frequency selection filtering function of the radio frequency signal of the transceiver channel in the electronic device. Multiple filters of the frequency bands such as V, P, L, S can be assembled according to actual needs, and can be applied to different circuit usage scenarios. If multi-stage filtering is required, multiple filter groups can be cascaded in the circuit. The present invention provides a universal miniaturized filter group with small size, flexible use, high process maturity, convenient maintenance and repair, which is beneficial to realize system miniaturization.

[0004] To achieve the above-mentioned object, the present invention provides a universal miniaturized filter group, including a multilayer ceramic substrate, a filter, a switch, a capacitor, and a circuit interconnection wiring;

[0005] Each layer of the multi-layer ceramic substrate is plated with a metal layer;

[0006] A plurality of filters are placed on the upper surface of the multilayer ceramic substrate, a cavity is dug out from the bottom layer of the multilayer ceramic substrate, and two switches are placed in the cavity of the bottom layer of the multilayer ceramic substrate;

[0007] Arranging circuit interconnection traces on the middle layer of the multilayer ceramic substrate;

[0008] The bottom layer of the multilayer ceramic substrate is provided with soldering pads, and the external interfaces of the radio frequency circuit, control circuit and power supply are connected to the soldering pads on the bottom layer of the multilayer ceramic substrate through circuit interconnection wiring, and are interconnected with the outside.

[0009] Furthermore, it also includes a metal cover plate, a metal surrounding frame and a ceramic cover plate;

[0010] A metal frame is welded around the upper surface of the multi-layer ceramic substrate, and a metal cover plate parallel to the upper surface of the multi-layer ceramic substrate is welded perpendicular to the metal frame;

[0011] The bottom layer of the multi-layer ceramic substrate is welded with a ceramic cover plate.

[0012] Furthermore, the filters are SAW filters of different models, the two switches are switches of the same model, the SAW filter bare chip is placed on the upper surface layer of the multilayer ceramic substrate by gluing with silicone rubber, and the two switches of the same model are placed in the cavity of the bottom layer of the multilayer ceramic substrate, and the capacitors, SAW filters and switches are respectively bonded to the metal layers of the multilayer ceramic substrate at their corresponding layers with gold wires.

[0013] Furthermore, the filters are gallium arsenide filters of different models, the two switches are switches of the same model, the gallium arsenide filter bare chip is placed on the upper surface of the multilayer ceramic substrate by means of conductive adhesive, and the two switches of the same model are placed in the cavity of the bottom layer of the multilayer ceramic substrate, and the capacitors, gallium arsenide filters and switches are respectively bonded to the metal layers of the multilayer ceramic substrate at their corresponding layers with gold wires.

[0014] Furthermore, the pads placed on the bottom layer of the multilayer ceramic substrate are spherical pads and are packaged in BGA.

[0015] Furthermore, eight filters of different types are placed on the upper surface of the multilayer ceramic substrate, and two eight-cut-in-one switches of the same type are placed in the cavity of the bottom layer of the multilayer ceramic substrate. When working, control instructions are sent to the two eight-cut-in-one switches of the same type at the same time, and the two eight-cut-in-one switches of the same type allow the signal to pass through the filter of the band where the signal is located according to the control instructions.

[0016] Furthermore, a vent hole is provided in the middle of the multilayer ceramic substrate, which can connect the cavity formed by the upper surface layer of the multilayer ceramic substrate, the metal cover plate and the metal surrounding frame and the cavity of the bottom layer of the multilayer ceramic substrate.

[0017] Furthermore, the multilayer ceramic substrate is an alumina ceramic substrate.

[0018] Furthermore, the ceramic cover plate welded to the bottom layer of the multi-layer ceramic substrate has a single-sided metal layer to achieve airtight packaging.

[0019] Beneficial effects:

[0020] The present invention provides a universal miniaturized filter group. Taking the V band as an example, the size of the 8-way SAW filter group at the traditional circuit level is about 30mm*25mm, and the size of the component using this architecture is only 19mm*13mm, which can replace the circuit originally composed of dozens of discrete devices. This not only greatly reduces the types and quantity of components at the component level, but also reduces the electromagnetic noise and signal interference caused by the nonlinearity of the device, and improves the electromagnetic compatibility characteristics of the system. The bottom layer of the traditional packaged SAW filter circuit has a large-area grounding pad, which makes it impossible to make through holes with other properties except ground on the back of the printed circuit board, which greatly limits the flexibility of the printed circuit board PCB design. All pins of the universal miniaturized filter group in the present invention, including a large number of grounding pins, are concentrated around the device, and the middle of the device does not interfere with any through holes on the back of the printed circuit board. When used, the printed circuit board PCB can be reasonably laid out to reduce the volume of the component. The circuit using this architecture can reduce the volume of each channel by 1 / 3 and reduce the cost by 1 / 4. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a principle diagram of a universal miniaturized filter group involved in an embodiment of the present invention;

[0022] Figure 2 This is a diagram of a surface substrate of a universal miniaturized filter group involved in an embodiment of the present invention;

[0023] Figure 3 is a general miniaturized filter bank switch layout diagram involved in an embodiment of the present invention;

[0024] Figure 4 is a second layer interconnection diagram of a universal miniaturized filter group involved in an embodiment of the present invention;

[0025] Figure 5 is the 12th layer interconnection diagram of the universal miniaturized filter group involved in the embodiment of the present invention;

[0026] Figure 6 is a 7th layer interconnection diagram of a universal miniaturized filter group involved in an embodiment of the present invention;

[0027] Figure 7 1 is a bottom substrate diagram of a universal miniaturized filter group involved in an embodiment of the present invention;

[0028] Figure 8 is a physical cross-sectional view of a universal miniaturized filter group involved in an embodiment of the present invention;

[0029] Fig. 9 is a schematic diagram of an eight-way filter group involved in an embodiment of the present invention;

[0030] Fig.10 It is a diagram of a substrate of an eight-way filter group involved in an embodiment of the present invention.

[0031] Description of reference numerals:

[0032] Among them: D1 and D2 are eight-to-one switches of the same model; Z1-Z8 are filters of different models; IN is the control instruction input port; OUT is the control instruction output port. DETAILED DESCRIPTION

[0033] At present, the pre-selection filter group of V, P, L, and S bands is usually implemented by SAW filters due to the limitation of volume and index. In order to make similar chip designs universal in the future, the largest die size that can match this package is used for design. Considering the V band as the background, the SAW filter is mounted on the upper surface. The size of a single filter is 3*2.2mm, and the edge is solid for airtight packaging and welding. Two SX325X switch dies and multiple chip capacitors are mounted in the cavity of the lower surface.

[0034] The preferred mechanism and implementation method of the present invention are further described below in conjunction with the accompanying drawings and specific implementation methods.

[0035] like Figures 1 to 10 As shown, the embodiment of the present invention discloses a technical solution for a universal miniaturized filter group.

[0036] Figure 1 is a principle diagram of a universal miniaturized filter group involved in an embodiment of the present invention; Figure 2 This is a diagram of a surface substrate of a universal miniaturized filter group involved in an embodiment of the present invention; Figure 3 is a general miniaturized filter bank switch layout diagram involved in an embodiment of the present invention;

[0037] Figure 4 is a second layer interconnection diagram of a universal miniaturized filter group involved in an embodiment of the present invention, Figure 4 For the control and power routing of the switch, the control power signal interface is led to the bottom circular pad through routing and vias; Figure 5 is the 12th layer interconnection diagram of the universal miniaturized filter group involved in the embodiment of the present invention, which is the control power supply signal interconnection between the switch and the filter; Figure 6 is a 7th layer interconnection diagram of a universal miniaturized filter group involved in an embodiment of the present invention, which is a radio frequency signal routing interconnecting the filter and the switch; Figure 7 1 is a bottom substrate diagram of a universal miniaturized filter group involved in an embodiment of the present invention; Figure 8 is a physical cross-sectional view of a universal miniaturized filter group involved in an embodiment of the present invention; Fig. 9 is a schematic diagram of an eight-way filter group involved in an embodiment of the present invention; Fig.10 It is a diagram of a substrate of an eight-way filter group involved in an embodiment of the present invention.

[0038] Example 1

[0039] A universal miniaturized filter group includes a multilayer ceramic substrate, a filter, a switch, a capacitor, and circuit interconnection wiring;

[0040] Eight filters are placed on the upper surface of the multilayer ceramic substrate, a cavity is dug out from the bottom layer of the multilayer ceramic substrate, and two switches and a plurality of capacitors for DC isolation and filtering are placed in the cavity of the bottom layer of the multilayer ceramic substrate;

[0041] Arranging circuit interconnection traces on the middle layer of the multilayer ceramic substrate;

[0042] The bottom layer of the multilayer ceramic substrate is provided with soldering pads, and the external interfaces of the radio frequency circuit, control circuit and power supply are connected to the soldering pads on the bottom layer of the multilayer ceramic substrate through circuit interconnection wiring, and are interconnected with the outside.

[0043] Example 2

[0044] The connection method of this embodiment is basically the same as that of embodiment 1, except that it further includes a metal cover plate, a metal frame and a ceramic cover plate, and the multilayer ceramic substrate is a 22-layer ceramic substrate;

[0045] The multilayer ceramic substrate is a 22-layer alumina ceramic substrate, which is sequentially the 1st, 2nd, ..., 21st, and 22nd ceramic layers, wherein the 1st to 12th ceramic layers have the same appearance; the 13th to 19th ceramic layers have the same appearance; and the 20th to 22nd ceramic layers (i.e., the bottom layer of the multilayer ceramic substrate) have the same appearance. The 1st layer is the upper surface layer, the 22nd layer is the bottom layer, and except for the exposed 1st, 13th, and 22nd layers, the others are all intermediate layers.

[0046] The corresponding metal layers are arranged from top to bottom, with a total of 23 layers, which are the 1st, 2nd, ..., 22nd metal layers, and also include the 23rd metal layer. The 23rd metal layer is a ball pad layer, using BGA packaging, and the ball is welded to the outside. The bottom ball or column is assembled to the printed circuit board to connect with other circuits.

[0047] Eight filters of different types are placed on the upper surface of the 22-layer alumina ceramic substrate, a cavity is dug out from the bottom layer of the 22-layer alumina ceramic substrate, and two eight-to-one switches of the same type are placed in the cavity of the bottom layer of the 22-layer alumina ceramic substrate;

[0048] Arrange circuit interconnection traces on the middle layer of the 22-layer alumina ceramic substrate;

[0049] Spherical pads are placed on the bottom layer of the 22-layer alumina ceramic substrate. The external interfaces of the RF circuit, control circuit and power supply are connected to the pads on the bottom layer of the multilayer ceramic substrate through circuit interconnection traces and are interconnected with the outside.

[0050] A metal frame is welded around the upper surface of the 22-layer alumina ceramic substrate, and a metal cover plate parallel to the upper surface of the 22-layer alumina ceramic substrate is welded perpendicular to the metal frame;

[0051] The bottom layer of the 22-layer alumina ceramic substrate is welded with a single-sided metal ceramic cover to achieve airtight packaging.

[0052] The 22-layer alumina ceramic substrate has an air hole in the middle, which can connect the cavity formed by the upper surface layer of the multi-layer ceramic substrate, the metal cover plate and the metal surrounding frame and the cavity of the bottom layer of the multi-layer ceramic substrate.

[0053] If the eight filters of different types are eight SAW filters of different types, the eight SAW filter bare chips are placed on the upper surface of the 22-layer alumina ceramic substrate by gluing with silicone rubber, two eight-cut-in-one switches of the same type are placed in the cavity of the bottom layer of the 22-layer alumina ceramic substrate, and the capacitors, SAW filters and switches are respectively bonded to the metal layers of the corresponding layers of the alumina ceramic substrate with gold wires.

[0054] If the eight filters of different models are eight gallium arsenide filters of different models, the eight gallium arsenide filter bare chips are placed on the upper surface layer of the 22-layer alumina ceramic substrate by means of conductive adhesive, two eight-cut-in-one switches of the same model are placed in the cavity of the bottom layer of the 22-layer alumina ceramic substrate, and the capacitors, SAW filters and switches are respectively bonded to the metal layers of the corresponding layers of the alumina ceramic substrate with gold wires.

[0055] When working, control instructions are sent to two 8-in-1 switches of the same model at the same time, and the signal passes through the corresponding filter according to the control instructions. It can be applied to various circuit scenarios that require segmented filtering, such as removing the combined spurious generated by the mixer when transmitting the signal; removing the harmonic spurious of the signal when receiving to ensure the signal quality. Various types of switches and filters can be selected according to actual needs during application.

[0056] The present invention provides a universal miniaturized filter group, which not only greatly reduces the types and quantities of component-level components, but also reduces the problem of electromagnetic noise and signal interference caused by the nonlinearity of the device, and improves the electromagnetic compatibility characteristics of the system.

[0057] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. However, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A universal miniaturized filter bank, characterized in that: Includes multi-layer ceramic substrates, filters, switches, capacitors, and circuit interconnection traces; Each layer of the multi-layer ceramic substrate is plated with a metal layer; A plurality of filters are placed on the upper surface of the multilayer ceramic substrate, a cavity is dug out from the bottom layer of the multilayer ceramic substrate, and two switches are placed in the cavity of the bottom layer of the multilayer ceramic substrate; Arranging circuit interconnection traces on the middle layer of the multilayer ceramic substrate; The bottom layer of the multilayer ceramic substrate is provided with soldering pads, and the external interfaces of the radio frequency circuit, control circuit and power supply are connected to the soldering pads on the bottom layer of the multilayer ceramic substrate through circuit interconnection wiring, and are interconnected with the outside.

2. The universal miniaturized filter bank according to claim 1, characterized in that: It also includes a metal cover plate, a metal frame and a ceramic cover plate; A metal frame is welded around the upper surface of the multi-layer ceramic substrate, and a metal cover plate parallel to the upper surface of the multi-layer ceramic substrate is welded perpendicular to the metal frame; The ceramic cover plate is welded to the bottom layer of the multi-layer ceramic substrate.

3. The universal miniaturized filter bank according to claim 1, characterized in that: The filters are SAW filters of different models, the two switches are switches of the same model, the SAW filter bare chip is placed on the upper surface of the multilayer ceramic substrate through silicone rubber bonding, and the two switches of the same model are placed in the cavity of the bottom layer of the multilayer ceramic substrate. The capacitors, SAW filters and switches are respectively bonded to the metal layers of the multilayer ceramic substrates of their corresponding layers with gold wires.

4. The universal miniaturized filter bank according to claim 1, characterized in that: The filters are gallium arsenide filters of different models, the two switches are switches of the same model, the gallium arsenide filter bare chip is placed on the upper surface of the multilayer ceramic substrate by conductive adhesive, and the two switches of the same model are placed in the cavity of the bottom layer of the multilayer ceramic substrate. The capacitors, gallium arsenide filters and switches are respectively bonded to the metal layers of the multilayer ceramic substrates of their corresponding layers with gold wires.

5. The universal miniaturized filter bank according to claim 1, characterized in that: The pads placed on the bottom layer of the multilayer ceramic substrate are spherical pads and are packaged in BGA.

6. The universal miniaturized filter bank according to claim 1, characterized in that: Eight filters of different types are placed on the upper surface of the multilayer ceramic substrate, and two eight-cut-one switches of the same type are placed in the cavity of the bottom layer of the multilayer ceramic substrate. When working, control instructions are sent to the two eight-cut-one switches of the same type at the same time, and the two eight-cut-one switches of the same type make the signal pass through the filter of the signal band according to the control instructions.

7. The universal miniaturized filter bank according to claim 1, characterized in that: The middle of the multilayer ceramic substrate is provided with an air hole which can communicate with the cavity formed by the upper surface layer of the multilayer ceramic substrate, the metal cover plate and the metal surrounding frame and the cavity of the bottom layer of the multilayer ceramic substrate.

8. The universal miniaturized filter bank according to claim 1, characterized in that: The multilayer ceramic substrate is an alumina ceramic substrate.

9. The universal miniaturized filter bank according to claim 2, characterized in that: The ceramic cover plate welded to the bottom layer of the multi-layer ceramic substrate has a single-sided metal layer to achieve airtight packaging.

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