A radio frequency splitting and monitoring circuit for a multilayer board internal structure

Abstract

This application provides a multilayer PCB-based radio frequency (RF) splitting and monitoring circuit. The RF splitting and monitoring circuit includes: a double-layer RF transmission layer, wherein the first RF transmission layer includes an embedded power divider, an isolation resistor, and a coaxial-like vertical transition structure; the second RF transmission layer includes an embedded power divider, an isolation resistor, a coupler based on a SICL transmission structure, a load resistor, and a 50-ohm coaxial-like vertical transition. This application is applicable to integrated front-ends and tile-type front-ends, where the RF circuitry is distributed within the three-dimensional layers according to different functions for array monitoring and array signal splitting or combining. It is an essential functional component of the RF array front-end, featuring good consistency and high integration. This invention has low manufacturing costs, is easy to integrate within a printed multilayer PCB, and is suitable for broadband integrated RF front-ends.

Description

Technical Field

[0001] This application relates to the field of radio frequency circuit technology, and in particular to a radio frequency splitting and monitoring circuit with a multilayer board structure. Background Technology

[0002] In the microwave array front end, the key functional components located between the transceiver components and the antenna unit are the signal power splitter network and the combining monitoring network. Conventionally, the network components are connected between the antenna and the transceiver components using cables or connectors. However, since the RF channels composed of antennas and components often have phase and amplitude consistency requirements, this primitive design method not only occupies a lot of space but also introduces a large number of human-induced system errors. Therefore, the design of RF splitter and monitoring circuits in a multi-layer board structure is essential. In addition to solving the above problems, it can also greatly reduce hardware costs after the equipment enters mass production.

[0003] Existing literature reports microstrip line-to-microstrip line transition structures, such as: Reference 1 (Research on microstrip power dividers in antenna feed networks, 2019 Master's Thesis); Reference 2 (Design of ultra-wideband RF adapter board based on microstrip multilayer board, Proceedings of the 2023 National Microwave and Millimeter Wave Conference); Reference 3 (Design and implementation of LTCC radar receiver front end, 2008 Master's Thesis).

[0004] Current research still has some problems: Reference 1 introduces a 24-port multilayer power divider network, which uses three layers of RF traces to achieve equal-phase power division of signals. The model has poor reusability and lacks coupling functionality. Reference 2 designs a microstrip multilayer board RF adapter connection method, but does not achieve power division coupling functionality. Reference 3 presents a power divider and coupler solution based on LTCC technology, but it does not form a network; instead, it is an independent RF channel. Furthermore, the product is based on LTCC technology, which inherently has high cost and long processing cycle, making it inflexible for engineering applications. Summary of the Invention

[0005] This application provides a multi-layer board-based radio frequency splitter and monitoring circuit. The compact and planar design of this multi-layer board-based radio frequency splitter and monitoring circuit, placed between the antenna unit and the transceiver assembly, facilitates integration and reduces human error.

[0006] This application is located within a multi-layer RF front-end board for highly integrated RF splitting and monitoring. It includes a dual-layer RF transmission layer, wherein the first RF transmission layer includes an embedded power divider, an isolation resistor, and a coaxial vertical transition structure.

[0007] From top to bottom, it includes RF 1 ground layer 1, substrate, RF 1 layer, adhesive material, substrate, and RF 1 ground layer 2; the first RF transmission layer is used for signal power division, and the branch terminal of the power divider is connected to the transmit input of the TR component;

[0008] The second RF transmission layer includes an embedded power divider, isolation resistors, a coupler based on SICL (substrate integrated coaxial line) transmission structure, a 50-ohm load resistor, and a coaxial-like vertical transition.

[0009] From top to bottom, it includes RF 2 ground layer 1, substrate, RF 2 layer, adhesive material, substrate, and RF 2 ground layer 2; the second RF transmission layer is used for signal monitoring and transmission; one end of the coupler is connected to the transmitter output of the TR component via a coaxial structure, and the other end is connected to the antenna via an external button structure to complete the signal connection.

[0010] The coupling port of the coupler is connected to the branch end of the power divider for signal monitoring;

[0011] Radio frequency transmission layers transmit data via a coaxial-like transition structure.

[0012] The in-layer transmission structure adopts SICL (substrate integrated coaxial cable) to ensure good electromagnetic compatibility of the complete circuit.

[0013] The radio frequency (RF) splitting and monitoring circuits are distributed three-dimensionally within the inner layers of the multilayer board, and consist of an RF network composed of built-in power dividers, couplers, etc.

[0014] Furthermore, the RF splitter and monitoring circuit includes three resistance values, two of which are used as isolation resistors. The resistance values ​​from the power divider's combining end to the branch end are 120Ω and 150Ω.

[0015] One of them is a load resistor, located at the end of the coupler isolation port, with a resistance of 50Ω. Both isolation resistors and the load resistor are made of chip sheet resistors on the inner layer of a multilayer board.

[0016] Furthermore, the RF branch and monitoring circuits consist of eight layers, housed within a multilayer board with more than eight layers;

[0017] If the layer distribution names are named X0 to X7 in order from top to bottom, then the RF branch circuit is arranged on layer X1 and the RF monitoring circuit is arranged on layer X5; among them, X0 to X3 and X4 to X7 can be interchanged.

[0018] Furthermore, the signal transmission transition between RF Layer 1 and RF Layer 2 adopts a quasi-coaxial vertical transition, and the signals between ports with the same function are in phase.

[0019] The advantages of this invention compared to the prior art are:

[0020] (1) This invention overcomes the shortcomings of the traditional RF front-end antenna and transceiver components having a large connection network size and large human system error. It uses a multi-layer board internal structure to realize RF branching and monitoring circuits, which is simple to process, easy to integrate, has small system error and compact structure.

[0021] (2) Compared with traditional circuits with the same function, the present invention has the characteristics of low cost, and the hardware cost is only the processing cost of multilayer boards;

[0022] (3) Compared with traditional circuits with the same function, the present invention has improved reliability and maintainability because it uses a complete multilayer board to connect the antenna and transceiver components, and there is no manual installation process in the later stage. Attached Figure Description

[0023] Figure 1 This is a hierarchical structure diagram;

[0024] Figure 2 This is a diagram of the surface structure of layer X1;

[0025] Figure 3 This is a diagram of the surface structure of layer X5;

[0026] Figure 4 This is a diagram showing the vertical interconnect structure between layers X1 and X5;

[0027] Figure 5 Location diagram of the square block

[0028] Figure 6 It is a coaxial vertical transition structure. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0030] This invention utilizes a multi-layer board internal structure for two-layer radio frequency transmission, and designs and solves the problems of miniaturized, highly integrated radio frequency branching and monitoring circuits according to functions, with a short processing cycle and relatively flexible engineering applications.

[0031] A multilayer board structure for RF splitting and monitoring circuitry utilizes eight printed circuit layers and can be placed within a multilayer board with more than eight layers. If the layers are named sequentially from X0 to X7, the RF splitter is located on layer X1, the RF detection circuit on layer X5, layers X0-3 form a single SICL (Substrate Integrated Coaxial Line) layer, and layers X4-7 form another SICL layer. RF signal transmission between these layers and to the outside is achieved through a coaxial-like structure composed of blind vias, through-vias, and buried vias. The power splitter network has two types of isolation resistors, and the coupling network has one type of load resistor; all resistors are implemented using an embedded sheet resistor design.

[0032] This application provides a multilayer board internal structure radio frequency splitter and monitoring circuit, using TSM-DS3M dielectric material. This material has many domestically produced alternatives. The layering and thickness are as follows... Figure 1 As shown in the figure. This implementation describes an X-band RF splitter and monitoring circuit network for a 16×4 array front end.

[0033] Figure 2 The surface structure is the X1 layer, which is the radio frequency splitter layer; Figure 3 The surface structure is an X5 layer, serving as the monitoring circuit network.

[0034] Figure 4 This is a vertical interconnect structure between layers X1 and X5; Figure 5 This indicates the location of the sheet resistance; the vertical transition uses... Figure 6 The structure shown is a coaxial structure.

[0035] The structure of this invention is suitable for the front end of radio frequency arrays and can be widely used and manufactured.

[0036] The embodiments described above do not constitute a limitation on the scope of protection of this application.

Claims

1. A radio frequency splitter and monitoring circuit with a multilayer board structure, characterized in that, The radio frequency splitter and monitoring circuit includes: It includes a dual-layer radio frequency transmission layer, wherein the first radio frequency transmission layer includes an embedded power divider, an isolation resistor, and a coaxial vertical transition structure. From top to bottom, it includes RF 1 ground layer 1, substrate, RF 1 layer, adhesive material, substrate, and RF 1 ground layer 2; the first RF transmission layer is used for signal power division, and the branch terminal of the power divider is connected to the transmit input of the TR component; The second RF transmission layer includes an embedded power divider, isolation resistors, a coupler based on the SICL transmission structure, a 50-ohm load resistor, and a coaxial vertical transition. From top to bottom, it includes RF 2 ground layer 1, substrate, RF 2 layer, adhesive material, substrate, and RF 2 ground layer 2; the second RF transmission layer is used for signal monitoring and transmission; one end of the coupler is connected to the transmitter output of the TR component via a coaxial structure, and the other end is connected to the antenna via an external button structure to complete the signal connection. The coupling port of the coupler is connected to the branch end of the power divider for signal monitoring; Radio frequency transmission layers transmit data via a coaxial-like transition structure. The intralayer transmission structure uses a substrate-integrated coaxial cable.

2. The radio frequency splitter and monitoring circuit according to claim 1, characterized in that, The RF splitter and monitoring circuit includes three resistance values, two of which are used as isolation resistors. The resistance values ​​from the power divider's combining end to the branch end are 120Ω and 150Ω, respectively. One type is the load resistor, located at the end of the coupler isolation port, with a resistance of 50Ω; both isolation resistors, as well as the load resistor, are made of surface-mount sheet resistors on the inner layer of a multilayer board.

3. The radio frequency splitter and monitoring circuit according to claim 1, characterized in that, The radio frequency branching and monitoring circuits consist of eight layers, housed within a multilayer board with more than eight layers. If the layer distribution names are named X0 to X7 in order from top to bottom, then the RF branch circuit is arranged on layer X1 and the RF monitoring circuit is arranged on layer X5; among them, X0 to X3 and X4 to X7 can be interchanged.

4. The radio frequency splitter and monitoring circuit according to claim 1, characterized in that, The signal transmission transition between RF Layer 1 and RF Layer 2 adopts a coaxial vertical transition, and the signals between ports with the same function are in phase.

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