Radio frequency packaging module and active phased array radar

Abstract

The embodiment of the utility model provides a radio frequency packaging module and an active phased array radar, and relates to the technical field of active phased arrays. The radio frequency packaging module comprises a top surface lead-out structure, a first substrate module, a metal cavity frame, a second substrate module and a bottom surface lead-out structure which are connected layer by layer. A space is formed among the first substrate module, the metal cavity frame and the second substrate module to accommodate a chip. The top surface lead-out structure is used for connecting an antenna, the bottom surface lead-out structure is used for leading out a chip to an external circuit board, double-sided lead-out is adopted, the contact path with an antenna end is short, and compared with a traditional T / R assembly, the T / R assembly is smaller in size and lower in loss.

Description

Technical Field

[0001] This application relates to the field of active phased array technology, and particularly to radio frequency packaging modules and active phased array radars. Background Art

[0002] The wide application of active phased array technology has enabled the rapid development of missile guidance, satellite communication, and radar fields. Therefore, higher requirements are put forward for the size, performance, integration, reliability, and cost of T / R (Transmit / Receive) components.

[0003] When T / R components are used in an array, the size, loss, and even cost of T / R components are particularly important. All pins of traditional T / R components need to be led out from the bottom surface, resulting in a large area, high radio frequency line loss, and low working efficiency.

[0004] How to make T / R components have the characteristics of high integration and low loss is the technical problem to be solved in this application. Utility Model Content

[0005] The purpose of this application is to provide a radio frequency packaging module and an active phased array radar, so that T / R components have the characteristics of high integration and low loss.

[0006] To achieve the above purpose, the embodiments of this application adopt the following technical solutions.

[0007] In a first aspect, the embodiments of this application provide a radio frequency packaging module, including a top surface lead-out structure, a first substrate module, a metal cavity frame, a second substrate module, and a bottom surface lead-out structure.

[0008] The top surface lead-out structure, the first substrate module, the metal cavity frame, the second substrate module, and the bottom surface lead-out structure are connected layer by layer;

[0009] A space is formed between the first substrate module, the metal cavity frame, and the second substrate module to accommodate chips;

[0010] The top surface lead-out structure is used to connect to an antenna;

[0011] The bottom surface lead-out structure is used to lead out the chips to an external circuit board.

[0012] Optionally, the cavity formed by the metal cavity frame includes an antenna channel cavity and a chip cavity, and the antenna channel cavity and the chip cavity are isolated by the metal cavity frame.

[0013] Optionally, the radio frequency packaging module has 4 radio frequency channels, the number of antenna channel cavities is 4, and the 4 antenna channel cavities are distributed at the four corners.

[0014] Optionally, the chip cavity includes two power cavities and an intermediate cavity; the power cavities are used to accommodate power modulation chips; the two power cavities are located on both sides of the intermediate cavity, and the metal cavity frame has axial symmetry.

[0015] Optionally, the top surface lead-out structure and / or the bottom surface lead-out structure is a BGA ball.

[0016] Optionally, the top surface lead-out structure includes a ground BGA ball and a radio frequency BGA ball; the radio frequency packaging module has four radio frequency channels, the number of antenna channel cavities is four, and the four antenna channel cavities are distributed at the four corners;

[0017] The first substrate module includes a first metal layer, a first ceramic substrate, and a second metal layer;

[0018] The first metal layer is provided with four first holes, and the four radio frequency BGA balls are located in the four first holes, and the ground BGA ball is connected to the first metal layer;

[0019] The second metal layer is provided with four second holes, and pads are arranged in the second holes;

[0020] The first ceramic substrate has first connection posts and second connection posts;

[0021] Each radio frequency BGA ball is connected to a pad in one of the second holes through the second connection post;

[0022] The first metal layer is connected to the second metal layer through the first connection post.

[0023] Optionally, the second substrate module includes a chip arrangement metal layer, a second ceramic substrate, and a metal lead layer;

[0024] The chip is disposed on the chip arrangement metal layer;

[0025] The second ceramic substrate has a plurality of lead connection posts; the chip arrangement metal layer is connected to the metal lead layer through the lead connection posts; the metal lead layer is connected to the bottom surface lead-out structure.

[0026] Optionally, the first substrate module is integrally formed by a direct copper plating on ceramic process, and the second substrate module and the metal cavity frame are integrally formed by a direct copper plating on ceramic process.

[0027] Optionally, the radio frequency packaging module is a Ku-band radio frequency packaging module.

[0028] In a second aspect, an active phased array radar provided by an embodiment of the present application includes the radio frequency packaging module of the first aspect.

[0029] Compared with the background art, the present application has the following beneficial effects:

[0030] For the radio frequency packaging module provided by the embodiment of the present application, since the bottom surface and the top surface are both used for lead-out, all antenna ports can be led out from the top surface. Compared with the way in the background art where the antenna is led out from the bottom surface and requires a long path to reach the antenna, this solution reduces the required area, has a short contact path with the antenna port, low loss, and high integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0032] Figure 1 Schematic diagram of a radio frequency packaging module provided by an embodiment of the present application;

[0033] Figure 2 Schematic diagram of a top surface lead-out structure and a first substrate module provided by an embodiment of the present application;

[0034] Figure 3 Schematic diagram of a metal cavity frame provided by an embodiment of the present application;

[0035] Figure 4 Schematic diagram of a Ku-band four-channel SIP circuit provided by an embodiment of the present application;

[0036] Figure 5 Schematic diagram of a second substrate module and a bottom surface lead-out structure provided by an embodiment of the present application;

[0037] Figure 6 Schematic diagram of a Ku-band radio frequency channel structure provided by an embodiment of the present application;

[0038] Figure 7 Schematic diagram of an S11 curve of a radio frequency channel at the antenna provided by an embodiment of the present application;

[0039] Figure 8 Schematic diagram of an S12 curve of a radio frequency channel at the antenna provided by an embodiment of the present application;

[0040] Figure 9 Schematic diagram of an isolation degree curve between adjacent radio frequency channels provided by an embodiment of the present application.

[0041] Description of the reference numerals:

[0042] 101 Top surface lead-out structure

[0043] 201 First metal layer

[0044] 202 First hole

[0045] 203 First ceramic substrate

[0046] 204 Connecting post

[0047] 205 Second metal layer

[0048] 206 Second hole

[0049] 301 Metal cavity frame

[0050] 302 Antenna channel cavity

[0051] 303 Power supply cavity

[0052] 304 Intermediate cavity

[0053] 401 Chip arrangement metal layer

[0054] 402 Second ceramic substrate

[0055] 403 Metal lead layer

[0056] 501 Bottom surface lead-out structure Detailed implementation manners

[0057] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. The described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Usually, the components of the embodiments of the present application described in the accompanying drawings here can be arranged and designed in various different configurations.

[0058] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the claimed present application, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts fall within the scope of protection of the present application. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0059] In the description of the present application, it should be noted that relative terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. The term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium.

[0060] Reference can be made to Figure 1 , the embodiment of the present application provides a radio frequency packaging module, including a top surface lead-out structure, a first substrate module, a metal cavity frame, a second substrate module, and a bottom surface lead-out structure. The top surface lead-out structure, the first substrate module, the metal cavity frame, the second substrate module, and the bottom surface lead-out structure are connected layer by layer.

[0061] A space is formed between the first substrate module, the metal cavity frame, and the second substrate module, and the space accommodates the chip. The top surface lead-out structure is used to connect the antenna, and the bottom surface lead-out structure is used to lead the chip to an external circuit board.

[0062] Due to the double-sided lead-out method of the bottom surface and the top surface, all antenna ports of the radio frequency packaging module can be led out from the top surface. Compared with the method in the background art that needs a longer path to reach the antenna when leading out from the bottom surface, this solution reduces the required area, has a short contact path with the antenna end, small loss, and high integration.

[0063] The radio frequency packaging module can have 4 radio frequency channels. The radio frequency packaging module can be rectangular, and the 4 radio frequency channels are located at the four corners of the rectangle, having a more compact effect. Taking the 4-channel implementation mode as an example, the structure of the radio frequency packaging module will be introduced layer by layer below.

[0064] The top surface lead-out structure can adopt the form of BGA (Ball Grid Array) balls. The BGA ball mounting process is mature and the cost is controllable. Figure 2 Shows the layer-by-layer schematic of the top surface lead-out structure and the first substrate module. The top surface lead-out structure 101 is a BGA ball, and a position where a BGA ball is missing can be formed in the middle of the top surface lead-out structure 101. Information such as the model of the device can be marked at the position where the BGA ball is missing.

[0065] Such as Figure 2 , the first substrate module includes a first metal layer 201, a first ceramic substrate 203, and a second metal layer 205.

[0066] There are connection posts 204 in the first ceramic substrate 203. According to functions, the connection posts 204 can be divided into first connection posts and second connection posts. The first connection posts and the second connection posts penetrate the upper and lower surfaces of the first ceramic substrate 203.

[0067] The first metal layer 201 is provided with four first holes 202. In the top surface lead-out structure 101, four BGA balls for connecting the antenna are located in the four first holes 202 and can be directly connected to the antenna, reducing the line loss. The remaining BGA balls are grounded by connecting to the first metal layer 201. The first metal layer 201 is connected to the second metal layer 205 through first connection posts.

[0068] The second metal layer 205 is provided with four second holes 206, and pads 207 are arranged in the second holes 206. Each BGA ball connecting the antenna is connected to one pad 207 through a second connection post. The sizes and spacings of the first holes 202, the second holes 206, and the pads in the holes can be adjusted according to the signal frequency of the radio frequency.

[0069] Below the first substrate module is a metal cavity frame, which can form an antenna channel cavity and a chip cavity. The antenna channel cavity and the chip cavity are isolated by the metal cavity frame, thus ensuring good isolation of the antenna signal.

[0070] The radio frequency packaging module has four radio frequency channels. For example, Figure 3 , the metal cavity frame 301 has four antenna channel cavities 302, and the four antenna channel cavities 302 are distributed at the four corners. A chip can be placed in the middle, which is convenient for layout.

[0071] For example, Figure 4 , taking the circuit of a Ku-band four-channel SIP (System in Package) as an example, there are a transmitting link and a receiving link, and the four antenna connection ports can be arranged at the four corners.

[0072] The chips involved in the transmitting link include a four-channel amplitude-phase multifunctional chip, a multifunctional power modulation chip, a power amplifier, and a switch chip.

[0073] The principle of the transmitting link is as follows: The external control protocol controller (which can be a controller in the form of an FPGA, etc.) inputs a signal to the four-channel amplitude-phase multifunctional chip to control the four-channel amplitude-phase multifunctional chip, so that the logic signal output by the four-channel amplitude-phase multifunctional chip controls the multifunctional power modulation chip, and then the multifunctional power modulation chip controls the on / off of the power amplifier and the switch chip to realize the operation of the transmitting link.

[0074] The chips involved in the receiving link include a four-channel amplitude-phase multifunctional chip, a multifunctional power modulation chip, a power amplifier and a switch chip (the switch is integrated in the power amplifier chip), a limiter chip, and a low-noise amplifier chip (abbreviated as LNA chip).

[0075] The principle is as follows: The external control protocol controller inputs signals to the four-channel amplitude-phase multifunctional chip to control the four-channel amplitude-phase multifunctional chip, so that the logic signals output by the four-channel amplitude-phase multifunctional chip control the multifunctional power modulation chip, and then the multifunctional power modulation chip controls the on / off of the power amplifier, switch chip, and low-noise amplifier chip, realizing the operation of the receiving link.

[0076] For example Figure 3 , the chip cavity can include two power cavities 303 and an intermediate cavity 304; the power cavities 303 are used to accommodate the multifunctional power modulation chips, and the remaining chips can be placed in the intermediate cavity 304. The two power cavities 303 are located on both sides of the intermediate cavity 304, and the metal cavity frame 301 has axial symmetry, so that better isolation can be achieved between the multifunctional power modulation chip and the antenna and other chips.

[0077] For example Figure 3 , the RF connection posts 305 are located in the antenna channel cavity 302. The RF connection posts 305 penetrate the antenna channel cavity 302 and connect the pads in the second hole 206 and the second substrate module. A semi-circular isolation wall can also be provided around the RF connection posts 305 in the antenna channel cavity 302 to better isolate the antenna signal from the power modulation chip.

[0078] Figure 5 Shows the layer-by-layer schematic of the second substrate module and the bottom surface lead-out structure. The second substrate module includes a chip arrangement metal layer 401, a second ceramic substrate 402, and a metal lead layer 403. The bottom surface lead-out structure 501 can be in the form of BGA balls.

[0079] The chips are arranged on the chip arrangement metal layer 401. There are multiple lead connection posts in the second ceramic substrate 402. The chip arrangement metal layer 401 is connected to the metal lead layer 403 through the lead connection posts, and the metal lead layer 403 is connected to the bottom surface lead-out structure 501.

[0080] Figure 2 、 Figure 4 The first substrate module and the second substrate module shown can be fabricated by the DPC (Direct plating copper) process. The specific steps are as follows: First, drill holes in the ceramic substrate, sputter copper to fill the holes to form connection posts, and the connection posts penetrate the upper and lower surfaces of the ceramic substrate; then copper is plated on both sides of the ceramic substrate with a thickness of dozens of microns, and the required patterns and pads are formed through processes such as photomask development. The substrate of the chip can be fixed to the surface of the second substrate module through conductive adhesive. The chips can be connected to each other and to the pads on the surface of the second substrate module through gold wires.

[0081] The first substrate module is integrally completed by the DPC process. The second substrate module is fabricated by the DPC process. Subsequently, chip micro-assembly and wire bonding are performed on the second substrate module. After that, copper plating is continued on the second substrate module to form a metal cavity frame. Then, the first substrate module and the metal cavity frame are welded, which can be welded by AuSn solder to form a reliable hermetic package.

[0082] In an implementation manner for the Ku band of this solution, the size of the RF packaging module is 14.5 mm × 14.5 mm × 2.8 mm. The cavity division processing of the metal cavity frame avoids cavity resonance generated in the Ku band and improves the isolation degree between channels.

[0083] Due to the strict application requirements of high-power RF front-end modules, when meeting the application requirements, the ceramic substrates used for packaging can be classified into LTCC (Low Temperature Co-fired Ceramic), HTCC (High Temperature Co-fired Ceramic), DPC, and DBC (Direct Copper Bond) according to the preparation technology. Among them, LTCC mainly uses metals such as gold, silver, and copper as conductors, with relatively small losses, but the manufacturing process is difficult, the cycle is long, and the cost is high; HTCC mainly uses metals such as tungsten, molybdenum, and manganese as conductors, with high reliability, corrosion resistance, and high temperature resistance, but large losses, high costs, and poor electrical conductivity of the materials, which will significantly reduce the efficiency of the bare chip when used in high-power RF modules; DBC has high reliability and small losses, but the circuit integration degree is not as good as that of HTCC and LTCC, the metal route is thick, usually 100 - 300 microns, and the flatness of copper is relatively poor compared with DPC, and the process is complex; DPC has good flatness, the metal route is generally dozens of microns, the circuit is more delicate, the loss is small, the cost is low, the processing cycle is shorter, and the heat dissipation performance is good. For the circuit architecture of this application, the DPC process not only realizes miniaturization but also reduces the package loss, saves costs, and has better heat dissipation performance.

[0084] When the DPC process and BGA balls are applied to the RF packaging module, except for the ceramic substrate and BGA balls, other metal layer materials are all copper. To ensure the weldability and reliability of bare chip micro-assembly and wire bonding, a certain thickness of nickel-palladium-gold can be electroplated on the outside of all copper layers.

[0085] From the pads on the upper surface of the first substrate module, through the first substrate module, RF connection posts, and the RF channel structure of the second substrate module as Figure 6 shown, this RF channel is used for both the transmission and reception of RF signals, improving the system integration degree. The simulation of the return loss performance of the RF channel connected to the antenna in the Ku band is as Figure 7As shown, the reflected energy is less than 1%, and the simulation of the radio frequency channel loss at the antenna is as Figure 8 shown, the loss is only 0.06 dB, achieving low loss. The simulation of the isolation between adjacent radio frequency channels is as Figure 9 shown. The solid line represents the isolation between adjacent radio frequency channels inside the module, and the dashed line represents the isolation between adjacent radio frequency channels connected to the antenna. The isolation between ports is all < -55 dB, while the isolation between traditional transceiver channels is basically around -40 dB.

[0086] In summary, the Ku-band four-channel radio frequency packaging module of the present application has low radio frequency port loss and high isolation, and can be used in radio frequency links with higher gain.

[0087] Based on the above embodiments, the embodiments of the present application further provide an active phased array radar, and the active phased array radar includes the above radio frequency packaging module.

[0088] Generally speaking, the present application proposes a radio frequency packaging module and an active phased array radar, which can achieve the following beneficial effects:

[0089] 1. When the solution of the present application is applied to the production of Ku-band four-channel SIP modules, the overall module size is small, only 14.5 mm × 14.5 mm × 2.8 mm, and the weight < 2 g, which is reduced by one or even several orders of magnitude compared with the volume and weight of traditional radio frequency T / R components, meeting the requirements of miniaturized applications.

[0090] 2. The radio frequency packaging module of the present application can realize port lead-out through the form of BGA balls on both sides. The BGA balls on the top surface can be directly connected to the antenna, shortening the path from the radio frequency port of the bare chip to the antenna feed end, thereby reducing the radio frequency loss of the line. And the brick-like connection between the antenna and the radio frequency packaging module is realized, reducing the usage area of the array antenna and the radio frequency packaging module on the PCB and improving the system integration. In addition, when applied to an active phased array radar, a high-density chip area is used for radio frequency port design, which can further reduce the usage area of the antenna and the radio frequency packaging module and improve the overall system integration.

[0091] 3. The radio frequency packaging module of the present application has lower cost, more mature process, shorter cycle and lower loss compared with HTCC and LTCC, and has more market advantages.

[0092] 4. A cavity structure for placing bare chips can be designed inside the radio frequency packaging module of the present application, avoiding cavity resonance when the bare chips work in the Ku band, improving the working efficiency of the bare chips. At the same time, the isolation between each channel is improved, and the radio frequency port has low loss, high isolation and can be used in radio frequency links with higher gain.

[0093] The device and system embodiments described above are merely illustrative. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement it without creative efforts.

[0094] The above is only a preferred specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A radio frequency packaging module, characterized in that: It includes a top surface lead-out structure, a first substrate module, a metal cavity frame, a second substrate module and a bottom surface lead-out structure; The top surface lead-out structure, the first substrate module, the metal cavity frame, the second substrate module and the bottom surface lead-out structure are connected layer by layer; A space is formed between the first substrate module, the metal cavity frame and the second substrate module to accommodate a chip; The top surface lead-out structure is used to connect the antenna; The bottom lead-out structure is used to lead the chip out to an external circuit board.

2. The radio frequency packaging module according to claim 1, characterized in that: The cavity formed by the metal cavity frame includes an antenna channel cavity and a chip cavity, and the antenna channel cavity and the chip cavity are isolated by the metal cavity frame.

3. The radio frequency packaging module according to claim 2, characterized in that: The RF packaging module has 4 RF channels, the number of the antenna channel cavities is 4, and the 4 antenna channel cavities are distributed at 4 corners.

4. The radio frequency packaging module according to claim 2, characterized in that: The chip cavity comprises two power supply cavities and a middle cavity; the power supply cavity is used to accommodate a power supply modulation chip; the two power supply cavities are located on both sides of the middle cavity, and the metal cavity frame has axial symmetry.

5. The radio frequency packaging module according to claim 1, characterized in that: The top surface lead-out structure and / or the bottom surface lead-out structure is a BGA ball.

6. The radio frequency packaging module according to claim 5, characterized in that: The top surface lead-out structure includes a ground BGA ball and a radio frequency BGA ball; The cavity formed by the metal cavity frame includes an antenna channel cavity and a chip cavity, and the antenna channel cavity and the chip cavity are isolated by the metal cavity frame; the RF packaging module has 4 RF channels, the number of the antenna channel cavities is 4, and the 4 antenna channel cavities are distributed at 4 corners; The first substrate module includes a first metal layer, a first ceramic substrate and a second metal layer; The first metal layer is provided with four first holes, the four RF BGA balls are located in the four first holes, and the grounding BGA ball is connected to the first metal layer; The second metal layer is provided with four second holes, and pads are provided in the second holes; The first ceramic substrate has a first connecting column and a second connecting column; Each of the RF BGA balls is connected to a pad in the second hole through the second connecting column; The first metal layer is connected to the second metal layer through the first connecting column.

7. The radio frequency packaging module according to claim 1, characterized in that: The second substrate module includes a chip arrangement metal layer, a second ceramic substrate and a metal lead layer; The chip is arranged on the chip arrangement metal layer; The second ceramic substrate has a plurality of lead connection columns; The chip arrangement metal layer is connected to the metal lead layer through the lead connection column; the metal lead layer is connected to the bottom lead-out structure.

8. The radio frequency packaging module according to claim 1, characterized in that: The first substrate module is integrally completed by a direct copper-plated ceramic process, and the second substrate module and the metal cavity frame are integrally completed by a direct copper-plated ceramic process.

9. The radio frequency packaging module according to claim 1, characterized in that: The radio frequency packaging module is a Ku-band radio frequency packaging module.

10. An active phased array radar, characterized in that: The active phased array radar comprises the radio frequency packaging module according to any one of claims 1 to 9.

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