A one-to-four power divider
By employing a two-stage transmission structure and an underlying microstrip isolation resistor network, the implementation challenge of a 1-to-4 power divider on a PCB was solved, achieving stable and efficient power distribution and isolation on the PCB.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- UNIV OF ELECTRONICS SCI & TECH OF CHINA
- Filing Date
- 2026-03-20
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies make it difficult to implement a 1-to-4 power divider on planar structures such as PCBs, mainly because the characteristic impedance of microstrip transmission lines is too high, causing the linewidth to exceed the processing limit, and the arrangement of isolation resistors makes it difficult to maintain the consistency of the four output ports.
A two-stage transmission structure is adopted, with an impedance transformation performed through the first and second transmission lines, and a second impedance transformation performed through the third transmission line. An isolation resistor network is arranged on the bottom microstrip in combination with vias and the bottom layer microstrip. Polytetrafluoroethylene glass fiber reinforced material is used as the dielectric to reduce the requirement for the characteristic impedance of a single transmission line, and an isolation resistor network is arranged on the bottom layer microstrip to achieve symmetry.
The requirement for transmission line characteristic impedance is significantly reduced, enabling the 1-to-4 power divider to be stably implemented on conventional PCB processes, and improving the isolation and amplitude/phase consistency of the output ports.
Smart Images
Figure CN122136600A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of radio frequency wireless technology, and in particular to a 1-to-4 power divider. Background Technology
[0002] Power dividers in radio frequency systems primarily distribute power, splitting a single signal into several signals according to a specific ratio to achieve different functionalities. Most existing power dividers are microstrip Wilkins structures, mainly composed of several quarter-wavelength (λ / 4) microstrip transmission lines. One end of these transmission lines is connected together to the signal input port, and the other end is connected to separate output ports. Each port also has a resistor connected to it, and the other ends of all these resistors are connected together, enabling power distribution and output port isolation.
[0003] However, a 1-to-4 power divider requires microstrip transmission lines with high characteristic impedance. If implemented on planar structures such as PCBs, the physical linewidth exceeds the limits of conventional PCB manufacturing processes, leading to design failure. Furthermore, maintaining consistency among the four output ports in the isolation resistor arrangement of a 1-to-4 power divider is difficult on a planar structure. Based on these two points, it is extremely difficult to implement a 1-to-4 power divider on planar structures such as PCBs. Summary of the Invention
[0004] The purpose of this invention is to provide a 1-to-4 power divider that can solve the problem of the difficulty in implementing a 1-to-4 power divider on planar structures such as PCBs.
[0005] To solve the above technical problems, embodiments of the present invention provide a 1-to-4 power divider, comprising: a top microstrip, a ground metal, and a bottom microstrip arranged from top to bottom, a first dielectric layer between the top microstrip and the ground metal, a second dielectric layer and a third dielectric layer between the ground metal and the bottom microstrip, and metal vias provided on the first dielectric layer, the second dielectric layer and the third dielectric layer. The top microstrip includes a first transmission line that connects to the input port. The first transmission line is routed in a serpentine pattern and its ends are connected to two second transmission lines and four third transmission lines. The two second transmission lines extend outward and their ends are suspended. The ends of the four third transmission lines are respectively connected to four output ports. The underlying microstrip contains four fourth transmission lines, and the first ends of the four fourth transmission lines are connected to the ends of the four third transmission lines through metal vias. The ends of the four fourth transmission lines are connected to one end of four resistors, and the other ends of the four resistors are connected to a common node.
[0006] Furthermore, the first layer, the second layer, and the third layer are all made of polytetrafluoroethylene glass fiber reinforced material.
[0007] Furthermore, the thickness of the first medium layer, the second medium layer, and the third medium layer is all 0.203 mm.
[0008] Furthermore, the width of the first transmission line is 0.66 mm, the width of the second and third transmission lines is 0.16 mm, and the width of the fourth transmission line is 0.38 mm.
[0009] The 1-to-4 power divider provided by this invention has at least the following beneficial effects: This invention utilizes a top-layer microstrip to complete power distribution and signal transmission. It employs a two-stage transmission structure (power distribution structure). The first and second transmission lines constitute the first-stage transmission structure, and the third transmission line constitutes the second-stage transmission structure. An impedance transformation is first performed through the first and second transmission lines, and then another impedance transformation is performed through the third transmission line. This distributes the impedance transformation required for the 1-to-4 power divider across two stages. Compared with a single-stage transformation, this significantly reduces the requirement for the characteristic impedance of a single transmission line segment, ensuring that the impedance of each transmission line segment falls within the range achievable by existing PCB processes. Simultaneously, the isolation resistor network is arranged on the bottom layer using vias and a bottom-layer microstrip (fourth transmission line), making the isolation resistor paths of the four output ports geometrically symmetrical. This is beneficial for improving the isolation and amplitude / phase consistency between the output ports.
[0010] The above double-layer layout avoids the need to forcibly arrange the isolation resistor network in the top plane, which alleviates the limitation of the planar layout on "four-output consistency" and is conducive to the stable implementation of the one-to-four power divider on conventional PCB processes. Attached Figure Description
[0011] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:
[0012] Figure 1 This is a schematic diagram of the structure of a 1-to-4 power divider provided by the present invention; Figure 2 This is a 3D view structural diagram of a 1-to-4 power divider provided by the present invention; Figure 3 This invention provides a schematic diagram of a 1-to-4 power divider. Figure 4 A schematic diagram of an even-mode power divider for a 1-to-4 power splitter provided by the present invention; Figure 5 The performance response diagram of a 1-to-4 power divider provided by the present invention. Detailed Implementation
[0013] 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 corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.
[0014] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
[0015] One embodiment of the present invention relates to a 1-to-4 power divider. The implementation details of the 1-to-4 power divider of this embodiment are described in detail below. The following implementation details are provided for ease of understanding and are not necessary for implementing this solution.
[0016] The specific structure of the 1-to-4 power divider in this embodiment can be as follows: Figure 1 As shown, it includes: a top microstrip, a ground metal, and a bottom microstrip arranged from top to bottom. A first dielectric layer is provided between the top microstrip and the ground metal, and a second dielectric layer and a third dielectric layer are provided between the ground metal and the bottom microstrip. Metal vias are provided on the first, second, and third dielectric layers (these metal vias serve to connect the top microstrip and the bottom microstrip and are not connected to the ground metal). The top microstrip includes a first transmission line that connects to the input port. The first transmission line is routed in a serpentine pattern and its ends are connected to two second transmission lines and four third transmission lines. The two second transmission lines extend outward and their ends are suspended. The ends of the four third transmission lines are respectively connected to four output ports. The underlying microstrip contains four fourth transmission lines, and the first ends of the four fourth transmission lines are connected to the ends of the four third transmission lines through metal vias. The ends of the four fourth transmission lines are connected to one end of four resistors, and the other ends of the four resistors are connected to a common node.
[0017] The first, second, and third dielectric layers are all made of polytetrafluoroethylene glass fiber reinforced material, and each has a thickness of 0.203 mm.
[0018] The width of the first transmission line is 0.66 mm, the width of the second and third transmission lines is 0.16 mm, and the width of the fourth transmission line is 0.38 mm.
[0019] Figure 2 A 3D view layout of the 1-to-4 power divider in this embodiment is provided. Figure 3The design principle of a 1-to-4 power divider is provided. The top microstrip includes a first transmission line Z1 connected to the input port Port1, which uses a serpentine routing pattern to reduce its footprint. Z1 connects to six transmission lines: two second transmission lines Z2 and Z3, and four third transmission lines Z4, Z5, Z6, and Z7. Z2 and Z3 extend outwards with their ends suspended. Z3, Z4, Z5, and Z6 connect to the output ports Port2, Port3, Port4, and Port5, respectively. Z4, Z5, Z6, and Z7 also connect to the bottom microstrip via metal vias, designated V1, V2, V3, and V4. The bottom microstrip has four fourth transmission lines Z8, Z9, Z10, and Z11. The beginnings of Z8, Z9, Z10, and Z11 connect to metal vias V1, V2, V3, and V4, respectively, and their ends connect to four resistors R1, R2, R3, and R4, with all four resistors connected together. Therefore, the top microstrip contains transmission lines Z1-Z7, and the bottom microstrip contains Z8-Z11. Among them, the top microstrip is the core of the 1-to-4 power divider and is the core component for realizing the function of the power divider.
[0020] In principle, a power divider functions as an impedance converter through transmission lines. For a 1-to-4 power divider, an impedance transformation from 50 ohms to 200 (4*50) ohms is required. Therefore, the characteristic impedance of the transmission lines needs to be 100 ohms (sqrt(50*4*50)). Since the characteristic impedance of a transmission line is inversely proportional to its physical linewidth, such a high characteristic impedance requires a physical linewidth that is less than the manufacturing capacity limit of the foundry. To solve this technical challenge, this embodiment uses a two-stage transmission structure to implement a 1-to-4 power divider. First, a transformation from 50 ohms to 25 ohms is achieved, and then a transformation from 25 ohms to 200 ohms is achieved. Z1, Z2, and Z3 satisfy the impedance change from 50 ohms to 25 ohms, requiring an impedance of 35.4 ohms. Z4, Z5, Z6, and Z7 achieve the impedance transformation from 25 ohms to 200 ohms, with each transmission line having an impedance of 70.7 ohms. The transmission line widths corresponding to these characteristic impedances meet the fabrication requirements, solving the difficulties of traditional structures, specifically addressing the problem of traditional 1-to-4 power dividers being unworkable on PCBs. Furthermore, to address the difficulty of resistor placement on the PCB, half-wavelength transmission lines are added at the ends of transmission lines Z4, Z5, Z6, and Z7 to increase resistor placement space. Additionally, to enhance bandwidth, two half-wavelength transmission lines are added at the end of Z1, one connected to the end of Z1 and the other open-circuited, ultimately forming the overall 1-to-4 power divider structure.
[0021] This embodiment of a 1-to-4 power divider achieves a planar implementation compared to traditional power dividers. In principle, the core design of a traditional power divider requires an impedance transformer; for a 1-to-4 power divider, this requires a 100 (sqrt(4*Z1*Z2)) ohm power divider. A 200-ohm characteristic impedance is very difficult to implement on a PCB, requiring transmission line widths typically smaller than the limits of foundry manufacturing capabilities, making planar implementation difficult with traditional structures. This embodiment proposes a two-stage transmission structure, using a two-stage impedance transformation structure to achieve the impedance transformation for a 1-to-4 split. Compared to traditional power dividers, this structure requires a significantly wider characteristic impedance for the transmission lines, making it achievable with current PCB manufacturing processes. Furthermore, by introducing a half-wavelength transmission line connection isolation resistor, the planar layout difficulties of the 1-to-4 power divider are avoided, providing greater design freedom. In addition, the 1-to-4 power divider designed in this embodiment was schematically designed and laid out using ADS tools and verified through electromagnetic simulation. It exhibits good 1-to-4 functionality and isolation capabilities, making it widely applicable in RF wireless communication scenarios. Theoretically, a 1-to-4 power divider should be designed using the extended parity-even mode analysis method. In practice, this requires first... Figure 3 The design schematic shown extracts common-mode points, merges branch circuits, and splits odd and even modes, as follows: Figure 4 As shown.
[0022] Therefore, the expression for the relevant quantity can be obtained: ; ; ; ; ; ; ; Then we can obtain the response expression for the 1-to-4 power divider: ; ; In the formula, Y is admittance, Z is impedance, θ is transmission line electrical length, Z0 is port impedance, and R is welding resistance. ae It is the admittance of the output port under odd mode, Y be It is the admittance of Z4 looking in to the right, Y c It is the admittance seen from the right side of Z1, Z ine Y is the impedance seen from the input port. ao It is the even-mode admittance of Z8, Y boIt is the even-mode admittance of Z4, Z ino It is the even-mode impedance of the input port.
[0023] For a 1-to-4 power divider, the required... S parameter S 11 =0; S 11 , S 21 , S 31 , S 41 , S 51 Both are equal to 1 / 4.
[0024] Based on this, the design of the 1-to-4 power divider in this embodiment is obtained.
[0025] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing the present invention, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of the embodiments of the present invention. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the embodiments of the present invention; therefore, the scope of protection of the embodiments of the present invention should be determined by the scope defined in the claims.
Claims
1. A 1-to-4 power divider, characterized in that, include: The top microstrip, ground metal, and bottom microstrip are arranged from top to bottom. A first dielectric layer is provided between the top microstrip and the ground metal, and a second dielectric layer and a third dielectric layer are provided between the ground metal and the bottom microstrip. Metal vias are provided on the first, second, and third dielectric layers. The top microstrip includes a first transmission line that connects to the input port. The first transmission line is routed in a serpentine pattern and its ends are connected to two second transmission lines and four third transmission lines. The two second transmission lines extend outward and their ends are suspended. The ends of the four third transmission lines are respectively connected to four output ports. The underlying microstrip contains four fourth transmission lines, and the first ends of the four fourth transmission lines are connected to the ends of the four third transmission lines through metal vias. The ends of the four fourth transmission lines are connected to one end of four resistors, and the other ends of the four resistors are connected to a common node.
2. The 1-to-4 power divider according to claim 1, characterized in that, The first layer, the second layer, and the third layer are all made of polytetrafluoroethylene glass fiber reinforced material.
3. The 1-to-4 power divider according to claim 2, characterized in that, The thickness of the first medium layer, the second medium layer, and the third medium layer is 0.203 mm.
4. The 1-to-4 power divider according to claim 1, characterized in that, The width of the first transmission line is 0.66 mm, the width of the second and third transmission lines is 0.16 mm, and the width of the fourth transmission line is 0.38 mm.