Deresistance broadband Wilkinson power divider and design method

Abstract

The invention provides a deblocking type broadband Wilkinson power divider and a design method, and belongs to the technical field of microwave radio frequency passive circuit devices. The power divider provided by the invention comprises a metal microstrip line structure, a dielectric substrate and a defected ground structure, the metal microstrip line structure comprises a shunt structure and a T-shaped resonant structure, and the metal structure is located at the top layer of the power divider; the dielectric substrate is used for placing the metal structure and the defected ground structure; the defected ground structure comprises a slot line structure, a slot line circle and a slot line circular ring; when an odd mode is excited, the central surface of the micro-strip slot line mixed structure is equivalent to an electric wall, the slot line structure is excited, and an electromagnetic field is divided into two paths of signals with equal amplitude and opposite phases after entering the defected ground structure, so that superposition cancellation is realized, and the effect is equivalent to an isolation resistor effect. According to the deblocking type broadband Wilkinson power divider and the design method provided by the invention, the processing cost is reduced, the circuit power capacity is improved, and the integration level of a system is improved.

Description

A de-blocking broadband Wilkinson power divider and its design method Technical Field

[0001] This application relates to the field of Wilkinson power divider technology, and more particularly to a de-blocking broadband Wilkinson power divider and its design method. Background Technology

[0002] In the field of microwave and radio frequency (RF) technology, power distribution and combining are crucial components supporting the operation of core electronic systems such as communications, radar, electronic warfare, and satellite navigation. With the rapid development of technologies such as low-Earth orbit (LEO) satellite communication, 5G millimeter-wave communication, and phased-array radar, RF front-end systems face higher demands on signal transmission stability, bandwidth coverage, power capacity, and integration. They not only need to achieve efficient signal distribution and combining but also adapt to the trend of miniaturized and high-density integrated equipment design, while simultaneously meeting the long-term reliable operation requirements in high-power scenarios. As the core passive device for signal distribution in the RF front-end, the performance of the power divider directly determines the signal quality and operational stability of the entire system, making it one of the key research directions in the current RF technology field.

[0003] Among various power divider types, Wilkinson power dividers are among the most widely used devices in microwave and radio frequency systems due to their clear principles, simple structure, high port isolation, and ease of engineering implementation. The core design concept of traditional Wilkinson power dividers is based on a quarter-wavelength transmission line combined with an isolation resistor topology. Impedance matching and power sharing are achieved through a quarter-wavelength transmission line with a characteristic impedance of √2Z0. A 2Z0 isolation resistor connected between the two output ports absorbs reflected signals and suppresses mutual interference between the output ports. With the evolution of microelectronics fabrication technology, Wilkinson power dividers have gradually transitioned from early waveguide and coaxial transmission line structures to planar structures based on microstrip lines and striplines, making them compatible with printed circuit board processes and meeting the integration needs of miniaturized devices. Furthermore, to increase power capacity, the industry has developed Gysel power dividers, which replace the single-path isolation resistor of the Wilkinson power divider with two ground-based isolation resistors to achieve power dissipation and heat dissipation, further adapting to the application requirements of medium- and high-power scenarios.

[0004] However, existing power divider designs based on isolation resistors still have significant drawbacks and cannot fully meet the development needs of current RF systems. On the one hand, traditional Wilkinson and Gysel power dividers rely on isolation resistors for port isolation. In high-power transmission or multi-stage cascaded applications, the isolation resistors are prone to overheating due to heat accumulation, which not only reduces device performance stability but may also cause resistor burnout and system failure. On the other hand, to achieve the integration of multi-layer power divider networks, the industry often uses buried resistor PCB hybrid bonding technology to embed the isolation resistors inside the PCB. This is not only limited by the number of integration layers and cannot meet the requirements of high-density integration, but the processing cost also increases sharply with the increase of the number of buried resistor layers, which is not conducive to the construction of low-cost RF systems. At the same time, the buried resistor process will further aggravate the heat accumulation problem, leading to increased system heat dissipation pressure and seriously affecting the long-term reliable operation of the devices. Summary of the Invention

[0005] In view of this, this application provides a de-blocking broadband Wilkinson power divider and a design method to reduce manufacturing costs and improve system integration.

[0006] Specifically, this application is achieved through the following technical solution: The first aspect of this application provides a de-blocking broadband Wilkinson power divider, the power divider comprising: a metal microstrip line structure, a dielectric substrate, and a defect ground structure; the metal microstrip line structure includes a shunt structure and a T-shaped resonant structure, the metal microstrip line structure being located at the top layer of the power divider; the dielectric substrate is used to place the metal microstrip line structure and the defect ground structure, the dielectric substrate being located below the metal microstrip line structure and above the defect ground structure; the defect ground structure includes a slotted line structure, a slotted line circle... The structure includes a microstrip line and a slotted ring; the metal microstrip line structure and the defect ground structure constitute a microstrip-slotted line hybrid transmission structure. The microstrip-slotted line hybrid structure supports even-mode signal transmission. When even-mode is excited, the center surface of the microstrip-slotted line hybrid structure is equivalent to a magnetic wall, and the slotted line structure is not excited, while the metal microstrip line structure transmits even-mode signals. When odd-mode is excited, the center surface of the microstrip-slotted line hybrid structure is equivalent to an electric wall, and the slotted line structure is excited. After entering the defect ground structure, the electromagnetic field is divided into two signals with equal amplitude and opposite phase. The two signals cancel each other out and are superimposed, achieving port isolation.

[0007] The second aspect of this application provides a design method for a de-impedanced broadband Wilkinson power divider. The method includes: designing initial parameters of a microstrip line splitter structure based on the standard impedance and power distribution requirements of the RF system; designing an initial shape of a resonant structure based on bandwidth adjustment and coupling requirements of odd-mode signals in the microstrip slot; designing an initial layout of a defective ground structure based on bandwidth and isolation improvement targets and odd-mode signal amplitude and phase modulation requirements; and optimizing the parameters of the initial layout to obtain the Wilkinson power divider.

[0008] This application provides a resistor-free broadband Wilkinson power divider and its design method. By replacing the isolation resistor in traditional Wilkinson power dividers with a defective ground structure, it solves the heat accumulation problem caused by the isolation resistor while ensuring the core performance of broadband, high isolation, and low loss. It also reduces manufacturing costs and integration complexity. Specifically, by removing the isolation resistor, which easily accumulates heat, heat can be rapidly dissipated through the large-area metal defective ground structure and the larger metal region, greatly improving heat dissipation efficiency and meeting the long-term reliable operation requirements of high-power scenarios. Combined with the synergistic effect of the upper T-shaped resonant structure and the lower defective ground structure, odd-mode signals are guided to form a 180° phase difference and cancel each other out, achieving high isolation. Furthermore, since the isolation resistor is eliminated, the problem of heat accumulation on the resistor is fundamentally solved, making this application suitable for high-power applications. Simultaneously, the multi-layer splitter / combiner network constructed based on this application does not require complex buried resistor processes; high-density integration can be achieved using only conventional PCB mixed-pressing processes, significantly reducing manufacturing costs and integration limitations. Attached Figure Description

[0009] Figure 1 is a schematic diagram of the structure of a first embodiment of the de-blocking broadband Wilkinson power divider provided in this application; Figure 2 is a schematic diagram of the structure of the branch structure shown in an exemplary embodiment of this application; Figure 3 is a schematic diagram of the structure of the T-shaped resonant structure shown in an exemplary embodiment of this application; Figure 3(a) is a schematic diagram of the structure of the first structure shown in an exemplary embodiment of this application; Figure 3(b) is a schematic diagram of the structure of the second structure shown in an exemplary embodiment of this application; Figure 4 is a schematic diagram of the structure of the defective ground structure shown in an exemplary embodiment of this application; Figure 5 is a flowchart of a second embodiment of the design method of the de-blocking broadband Wilkinson power divider provided in this application; Explanation of reference numerals: 1: metal microstrip line structure; 2: dielectric substrate; 3: defective ground structure; 11: signal input port; 12: impedance transformation stub; 13: two branch output ports; 31: slot line structure; 32: slot line circle; 33: slot line ring. Detailed Implementation

[0010] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0011] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used herein are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0012] It should be understood that although the terms first, second, third, etc., may be used in this application to describe various information, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0013] The following specific embodiments are given to illustrate the technical solution of this application in detail.

[0014] Figure 1 is a structural schematic diagram of Embodiment 1 provided in this application. Referring to Figure 1, the power divider provided in this embodiment includes a metal microstrip line structure 1, a dielectric substrate 2, and a defect ground structure 3; the metal microstrip line structure 1 includes a shunt structure and a T-shaped resonant structure, and the metal microstrip line structure is located on the top layer of the power divider; the dielectric substrate 2 is used to place the metal microstrip line structure 1 and the defect ground structure 3, and the dielectric substrate 2 is located below the metal microstrip line structure 1 and above the defect ground structure 3; the defect ground structure 3 includes a slot line structure 31, a slot line circle 32, and a slot line ring 33; the metal microstrip line structure 1 includes a metal microstrip line structure 1, a dielectric substrate 2, and a defect ground structure ... The line structure 1 and the defective ground structure 3 constitute a microstrip slot-line hybrid transmission structure. The microstrip slot-line hybrid structure supports even-mode signal transmission. When even-mode is excited, the center surface of the microstrip slot-line hybrid structure is equivalent to a magnetic wall, and the slot-line structure is not excited. The microstrip line branch structure transmits even-mode signals. When odd-mode is excited, the center surface of the microstrip slot-line hybrid structure is equivalent to an electric wall, and the slot-line structure is excited. After entering the defective ground structure, the electromagnetic field is divided into two signals with equal amplitude and opposite phase. The two signals cancel each other out and are superimposed, achieving port isolation.

[0015] Optionally, the microstrip line splitter structure includes a signal input port 11, an impedance transformation stub 12, and two splitter output ports 13, wherein the impedance transformation stub 12 is located between the signal input port 11 and the two splitter ports 13.

[0016] Optionally, the T-shaped resonant structure is located between the two branch output ports, the first structure of the T-shaped resonant structure is used to close the impedance transformation stub, and the second structure of the T-shaped resonant structure is parallel to the two branch output ports.

[0017] Optionally, the input port is used to input radio frequency electrical signals, and the two branch ports are used to output radio frequency electrical signals with equal amplitude and in phase.

[0018] Optionally, the dielectric substrate is an insulating support carrier, and the dielectric substrate, the metal microstrip line structure, and the defect ground structure enable impedance matching of the Wilkinson power divider.

[0019] Optionally, the dielectric substrate is an insulating support carrier. By selecting a suitable dielectric constant and substrate thickness, and coordinating the microstrip line width and length with the slot line width and length, a specific impedance matching circuit is formed.

[0020] Optionally, according to broadband design requirements, the initial parameter of the slot line circle radius is equal to the radius of the arc formed by the microstrip impedance transformation stub; to ensure high microstrip slot line coupling efficiency, the first structure closes the impedance transformation stub, and the initial linewidth of the second structure is the same as the input and output microstrip line width; the initial width of the slot line is set to be the same as the input and output microstrip line width, and the initial length is equivalent to a quarter wavelength of the center frequency; to meet broadband isolation requirements, the initial linewidth of the annular slot line is set to twice the microstrip linewidth, and the initial radius of the annular slot line is set to twice the radius of the arc formed by the slot line circle and the microstrip impedance transformation stub.

[0021] Furthermore, impedance matching refers to ensuring that the input ports, transmission paths, and output ports connected to upstream and downstream devices of the power divider maintain consistent impedance values. When the impedance of the entire signal transmission link is uniform, the input RF signal can be transmitted from the input end to the output end to the maximum extent, without signal reflection, power waste, or waveform distortion caused by impedance inconsistencies. The dielectric constant and thickness of the substrate determine the signal propagation characteristics within the substrate, directly affecting the impedance performance of the metal microstrip line and the defect ground structure. The linewidth and length of the metal microstrip line structure, as well as the slot width and ring size of the defect ground structure, further precisely adjust the impedance values ​​of each part. Through mutual matching and synergistic optimization, the overall impedance of the power divider is made consistent with the standard impedance of the RF system, forming a reflection-free and low-loss transmission path.

[0022] Optionally, the slotted structure is used to connect the slotted circle and the slotted ring. The slotted structure is excited during odd-mode excitation. After entering the slotted ring, the electromagnetic field is divided into two signals with equal amplitude and opposite phase, achieving superposition and cancellation.

[0023] Specifically, the superposition and cancellation mechanism means that two signals that would normally be transmitted to their respective ports cancel each other out after superposition, thus improving port isolation. Further improvements in power and heat dissipation stem from the fact that traditional Wilkinson power dividers require isolation resistors, which absorb reflected signals and generate heat. At higher power levels, these resistors are less effective at dissipating heat, limiting the circuit's power capacity. Because this structure replaces the traditional isolation resistors, heat does not accumulate, resulting in higher power capacity and better heat dissipation than previous devices.

[0024] Specifically, Figure 2 is a schematic diagram of the shunt structure shown in an exemplary embodiment of this application, Figure 3 is a schematic diagram of the T-shaped resonant structure shown in an exemplary embodiment of this application, Figure 3(a) is a schematic diagram of the first structure shown in an exemplary embodiment of this application, Figure 3(b) is a schematic diagram of the second structure shown in an exemplary embodiment of this application, and Figure 4 is a schematic diagram of the defective ground structure shown in an exemplary embodiment of this application. Please refer to Figures 1, 2, 3 and 4 simultaneously.

[0025] Furthermore, the radio frequency signal is input from the input port of the metal microstrip line structure 1 branch structure, and after impedance matching is completed through the impedance transformation stub, it is evenly distributed to the two branch ports.

[0026] Specifically, the core function of power distribution is achieved by the branching structure within the metallic microstrip line structure. This branching structure evolved from the traditional Wilkinson power divider, employing an axisymmetric design of input port – impedance transformation stub – branch port. The initial impedance of both the input port and the two branch ports is designed to be 50Ω, conforming to RF system standard impedances and ensuring no reflection loss during signal input and output. The impedance transformation stub connecting the input port and the branch ports has an impedance of 70.7Ω and a length equivalent to a quarter wavelength, enabling distortion-free transmission and uniform distribution of the input signal, ensuring consistent amplitude between the two output signals. Simultaneously, the axisymmetric layout of the branching structure ensures phase synchronization between the two output signals, with their phase curves essentially overlapping, meeting the RF system's requirements for signal phase consistency. When even-mode excitation occurs, the structure center acts as a magnetic wall, equivalent to an open circuit. The defective ground structure is not excited, and the microstrip line branching structure is responsible for transmitting the even-mode signal, achieving equal-amplitude and in-phase power distribution.

[0027] Furthermore, the upper metal microstrip line structure and the lower defect ground structure work together to form a hybrid structure that combines the transmission characteristics of microstrip lines and slot lines, adapting to different signal transmission modes. To broaden the operating bandwidth of the power divider, a circular stub is set at the end of the slot line in the hybrid structure. As a conventional topology for terminating a quarter-wavelength slot line, the circular stub has uniform impedance and a fixed length, which can adjust the impedance characteristics and resonant frequency of the slot line, allowing the structure to maintain good signal transmission performance over a wider frequency band and avoiding performance degradation caused by frequency band changes. The hybrid structure can support both odd and even signal transmission modes, and exhibits different operating states in the two modes, respectively realizing signal distribution and isolation functions. When encountering even-mode excitation, the center of the structure acts like a magnetic wall, and the slot lines are not activated. The signal is mainly transmitted through the upper microstrip line splitting structure, ensuring that the even-mode signal can be stably and distortion-free distributed to the output port. When encountering odd-mode excitation, the center of the structure acts like an electric wall, and the slot lines are activated. The electromagnetic field enters the annular slot and splits into two paths. The amplitudes of these two electromagnetic fields are exactly the same, but their phases are opposite, and they cancel each other out during propagation. This effectively suppresses port crosstalk caused by odd-mode signals, thereby significantly improving the isolation between output ports. Its effect is equivalent to that of the isolation resistor in a traditional Wilkinson power divider, but it does not rely on physical resistors, fundamentally solving the problems of resistor heat dissipation and integration.

[0028] Furthermore, during power distribution, if there is no effective isolation between the two branch ports, when the load on one branch port changes (e.g., open circuit, short circuit, or impedance mismatch), the reflected signal will interfere with the normal signal output of the other branch port through electromagnetic coupling between the ports. This results in amplitude distortion and phase shift of the output signal, affecting the stability of the system signal transmission. Moreover, crosstalk between branch ports reduces the signal-to-noise ratio, especially in multi-stage cascaded or high-power transmission scenarios, where accumulated crosstalk can lead to the performance collapse of the entire RF front-end system. Therefore, signal isolation between the two branch ports is necessary to ensure that load changes or interference signals on a single port do not affect the normal operation of other ports, guaranteeing the reliability of power distribution and signal integrity.

[0029] Furthermore, referring to Figure 3(a), in the T-shaped resonant structure of the metallic microstrip line structure, the I-shaped portion of the first structure encloses two impedance transformation stubs. When odd-mode excitation occurs, the center of the structure acts as an electric wall, and the shunt port is grounded through the first structure. The first structure couples the electromagnetic signal transmitted on the microstrip line to the slot line; after the slot line structure is excited, the electromagnetic signal is fed into the annular slot and split into two, with equal amplitudes and opposite phases, thus canceling each other out and improving port isolation.

[0030] Furthermore, please continue to refer to FIG. 4. The defected ground structure replaces the isolation resistor in the traditional Wilkinson power divider through the logic of guiding odd-mode signals + phase regulation + superposition cancellation, achieving resistor-free isolation. The defected ground structure 3 consists of an integrated layout of a slot line structure 31, a slot line circle 32, and a slot line ring 33, which is organically combined with the T-shaped structure to provide a specific propagation path for odd-mode signals. The T-shaped first structure, as a microstrip line and slot line mode coupling structure, guides the fed odd-mode signals to the slot line structure 31. The length, width of the slot line structure 31, and the radius of the slot line circle, as well as the width and radius of the slot line ring 33, can be optimized through pre-modeling, enabling the odd-mode signals to propagate in the slot line structure 31, enter the slot line ring, and split into two with equal amplitudes and opposite phases. The slot width of the slot line ring needs to be wider than that of the slot line, and the radius of the ring is also larger than the radius of the slot line stub, so as to cancel the superposition of wider-band signals, thereby completely suppressing the signal crosstalk between the shunt ports and achieving broadband and efficient isolation. In addition, the slot line circle structure, as the topology of a conventional terminal short-circuited quarter-wave slot line, can be regarded as a terminal short-circuited stub with uniform impedance and a determined length, which can improve the working bandwidth of the device.

[0031] Furthermore, in addition to achieving isolation, the defected ground structure also cooperates with the metal microstrip line structure to greatly improve the heat dissipation capacity of the power divider. The traditional power divider relies on an isolation resistor to achieve isolation, and the resistor itself is the core component for heat accumulation. Especially in high-power or multi-stage cascaded scenarios, it is difficult to dissipate heat, which easily leads to device damage. In this embodiment, the isolation resistor is removed, and the heat is no longer concentrated on a single component. Instead, it is quickly conducted and diffused through the large-area metal transmission lines of the metal microstrip line structure and the metal ground plane of the underlying defected ground structure. The heat dissipation area is much larger than that of the traditional isolation resistor, ultimately meeting the long-term reliable use requirements of high-power scenarios.

[0032] Furthermore, please refer to FIG. 3(b). The second structure shown is an E-shaped resonant structure formed by the T-shaped resonant structure and partial branches of two output ports. It achieves bandwidth expansion, odd-mode signal guiding, and isolation optimization through structural cooperation. On the one hand, the "|" - shaped part parallel to the output port branch in the second structure has a length that can be flexibly adjusted to change the structural resonance frequency, thereby broadening the working frequency band of the power divider and ensuring good impedance matching and low-loss characteristics within a wide frequency band. On the other hand, the second structure cooperates with the straight-shaped part of the first structure to accurately guide the odd-mode signals between the shunt ports, creating conditions for feeding them into the underlying defected ground structure. At the same time, through the multi-branch resonance effect of the E-shaped structure, the ability to constrain and regulate odd-mode signals is further enhanced, ultimately improving the isolation between the shunt ports and ensuring the stability of power distribution and signal integrity.

[0033] Optionally, the metal microstrip line structure and the defective ground structure constitute a microstrip slotted line hybrid transmission structure; the slotted line ends of the defective ground structure are circular stubs, and the operating bandwidth is improved by adjusting the slotted line width, length and circular radius; the structural resonance is adjusted by adjusting the line width and line length of the T-shaped resonant structure; and the bandwidth and isolation are optimized by adjusting the slotted line width and the size of the slotted line ring.

[0034] Specifically, to broaden the operating bandwidth of the power divider, the ends of the slot lines in the defective structure are designed with circular stubs. By adjusting the width of the slot lines, the smoothness of current transmission and impedance matching effect are affected; by adjusting the length of the slot lines, the path and phase characteristics of the signal propagation in the slot lines are determined; by adjusting the radius of the circular stubs at the ends of the slot lines, the resonant characteristics are changed, allowing the structure to maintain stable transmission over a wider frequency band and avoiding signal reflection or increased loss due to frequency changes, thereby improving the operating bandwidth of the Wilkinson power divider.

[0035] Furthermore, changes in the linewidth of the T-shaped resonant structure affect its equivalent impedance, while adjustments to the line length directly alter the resonant frequency. By optimizing the linewidth and line length of the T-shaped resonant structure, the resonant frequency band of the T-shaped resonant structure can be precisely matched with the target operating frequency band of the power divider, further broadening the effective operating bandwidth and enhancing the coupling capability for odd-mode signals.

[0036] Furthermore, by adjusting the width of the slot line itself, in conjunction with the aforementioned bandwidth optimization, the impedance matching effect is further refined. By adjusting the parameters of the slot line ring in the defective ground structure, including the width of the slot line and the overall size of the ring, the parameters of the slot line ring affect the propagation path and phase modulation accuracy of odd-mode signals. Optimization allows odd-mode signals to form a stable reverse phase superposition within the ring, more thoroughly canceling interference signals, improving port isolation, and ensuring good signal transmission quality across a wide frequency band, ultimately achieving dual optimization of bandwidth and isolation.

[0037] Furthermore, the dielectric substrate needs to meet the fabrication requirements of low dielectric constant, low loss tangent, high temperature stability, and good mechanical strength. Rogers 5880 substrate can be used to fabricate the dielectric substrate, with a relative dielectric constant of 2.2 and a loss tangent of 0.0009, and a thickness of 0.127 mm. The microstrip line width and length are calculated to meet the requirements of an input / output characteristic impedance of 50 Ω, a transformation stub characteristic impedance of 70.7 Ω, and a transformation stub length equal to an equivalent quarter-wavelength line length. The radius of the transformation stub is then determined based on this.

[0038] Furthermore, when the power divider is working, the input signal is distributed to the two output ports via the splitting structure. When the even mode is excited, the center of the structure is a magnetic wall, and the microstrip line splitting structure is responsible for transmitting the even mode signal, realizing the function of equal amplitude and in-phase power distribution.

[0039] Furthermore, if there is no effective isolation between the two branch ports, the reflected signal will interfere with the normal signal output of the other branch port through electromagnetic coupling between the ports, resulting in amplitude distortion and phase shift of the output signal, affecting the stability of the system signal transmission. Odd-mode transmission can be used to analyze port isolation problems. In this case, the first structure of the T-shaped resonant structure, connected to the branch port, guides the odd-mode signal to itself. Then, through the electromagnetic coupling effect of the upper metal-dielectric substrate-bottom trench line, the odd-mode signal is fed into the trench line structure of the bottom defect ground structure, and then enters the trench line circular branch, thus splitting into two, achieving equal amplitude and phase inversion, superposition and cancellation, and improving port isolation.

[0040] Furthermore, the initial parameter of the slot line circle radius is equal to the radius of the arc formed by the microstrip impedance transformation stub; to ensure high microstrip slot line coupling efficiency, the first structure of the "T" structure closes the impedance transformation stub, and the initial linewidth of the second structure is the same as the input and output microstrip line width; the initial width of the slot line is set to be the same as the input and output microstrip line width, and the initial length is equivalent to a quarter wavelength of the center frequency; to meet broadband isolation, the initial linewidth of the annular slot line is set to twice the microstrip linewidth, and the initial radius of the annular slot line is set to twice the radius of the arc formed by the slot line circle and the microstrip impedance transformation stub.

[0041] Furthermore, by optimizing the parameters of each component in the defective structure, such as the length and width of the slot line, the radius of the slot line circle, and the width and radius of the slot line ring, the second structure can expand the bandwidth and optimize the isolation index. At the same time, by adjusting the input and output linewidths and the line length and radius of the impedance transformation structure, it is ensured that the input and output impedances are basically matched with the standard 50Ω characteristic impedance under broadband conditions.

[0042] Furthermore, the design process can be aided by electromagnetic simulation software such as CST and HFSS, and optimization algorithms can be introduced to optimize multiple parameters simultaneously, thereby shortening the design cycle.

[0043] The de-resistance broadband Wilkinson power divider provided in this embodiment replaces the traditional isolation resistor with a defective ground structure, fundamentally solving the heat accumulation problem caused by the reliance on resistors in traditional power dividers. The heat generated during operation can be rapidly dissipated through the large-area metal ground plane at the bottom and the upper metal microstrip line structure, effectively meeting the long-term reliable operation requirements of high-power scenarios. The branching structure in the upper metal microstrip line structure adopts an axisymmetric design, coupled with precise impedance matching, ensuring that the input signal can be evenly distributed into two output signals of equal amplitude and in phase, guaranteeing the integrity and stability of signal transmission. The synergistic effect of the T-shaped resonant structure and the defective ground structure can efficiently guide the odd-mode transmission mode. Through a specific structural layout, the odd-mode signals are made to have equal amplitude and inverse phase and cancel each other out, significantly suppressing signal crosstalk between ports and achieving high isolation performance. Meanwhile, based on the multi-layer splitter / combiner network of this application, high-density integration of the multi-layer splitter / combiner network can be achieved through conventional printed circuit board mixing and bonding processes without the need for complex buried resistor processes, which greatly reduces processing costs and integration difficulty. Moreover, it maintains low loss characteristics over a wide frequency band, providing a solution for RF front-end systems that combines high performance, high reliability and economy, and is suitable for various application needs in high-frequency communication, radar and other fields.

[0044] Corresponding to the aforementioned embodiment of a de-blocking broadband Wilkinson power divider, this application also provides an embodiment of a design method for a de-blocking broadband Wilkinson power divider.

[0045] Figure 5 is a flowchart of Embodiment 2 of the design method for the de-blocking broadband Wilkinson power divider provided in this application. Referring to Figure 5, the method provided in this embodiment includes: S101, designing the initial parameters of the branch structure according to the standard impedance of the RF system and the power distribution requirements.

[0046] Specifically, the core components of the branch structure are determined, including one signal input port, two impedance transformation stubs, and two branch ports. The two branch ports and the two impedance transformation stubs are axially symmetrically distributed with respect to the extension line formed by the signal input port. Based on the standard impedance of the RF system, the initial linewidth of the signal input port and the two branch ports are set to ensure that the impedance of each port matches the standard impedance of the system. According to the power sharing requirements, the initial linewidth and line length of the impedance transformation stubs are set so that the impedance of the impedance transformation stubs meets the impedance matching conditions required for power sharing, and the line length is an equivalent quarter wavelength.

[0047] Furthermore, the power splitting structure is evolved from the traditional Wilkinson power divider. The axisymmetric layout is the basis for ensuring the equal-amplitude and in-phase output of the two power splitting ports. Therefore, the symmetric relationship of each component needs to be determined at the initial stage of design. Based on the central axis of the signal input port, the two impedance transformation branches are symmetrically distributed on both sides. The two power splitting ports are respectively located at one end of the two impedance transformation branches far from the input port to ensure that the signal transmission path lengths are the same. The standard impedance of the RF system is usually a general industry specification. Based on this, the initial line widths of the input port and the power splitting ports are designed. Through the impedance calculation function of the RF circuit design software, combined with parameters such as the dielectric constant and thickness of the selected dielectric substrate, the port impedance is accurately matched to avoid signal reflection loss at the ports and lay a foundation for the efficient transmission of signals.

[0048] Furthermore, the power equalization requires that the impedance transformation branches need to achieve a smooth transition from the input port impedance to the power splitting port impedance. Its impedance value needs to be calculated and determined by the power distribution principle. This impedance value is the key to evenly distributing one input signal to the two output ports. At the same time, the line length of the impedance transformation branch is designed to be an equivalent quarter wavelength because the quarter wavelength transmission line has impedance transformation characteristics and can convert the impedance of the input port to the impedance adapted to the power splitting port through the transformation branch to ensure distortionless power distribution. The guided wavelength of the signal in the dielectric is calculated through the dielectric constant of the dielectric substrate, and then the physical line length corresponding to the quarter guided wavelength is determined. Combining the impedance value calculation results, the initial line width and line length of the impedance transformation branch are finally determined. Optionally, the characteristic impedance of the input and output is 50Ω, and the impedance transformation branch ensures a characteristic impedance of 70.7Ω and a length of an equivalent quarter wavelength transmission line.

[0049] S102. Design the initial form of the resonant structure according to the coupling requirements of bandwidth adjustment and the odd-mode signal of the microstrip slot line.

[0050] Specifically, determine the installation position of the resonant structure so that it is located between the two power splitting ports and adjacent to the impedance transformation branches of the power splitting structure. Design the resonant structure as a "T" shape. Its first part is set as a "-" shape, spanning and closing the two impedance transformation branches. The second part is set as a "|" shape, vertically connected to the middle of the first part and parallel to the partial branches of the two power splitting ports. According to the bandwidth adjustment requirements, set the initial length of the second part of the "T" - shaped resonant structure so that the first part, the second part and the partial branches of the two power splitting ports form an "E" - shaped resonant unit.

[0051] Furthermore, the adoption of a "T"-shaped structure is based on the dual considerations of odd-mode signal guidance and resonance adjustment. The first part ("I"-shaped) is designed as a horizontal metal strip, the length of which matches the spacing between the two impedance transformation stubs, closing the arcs of the two impedance transformation stubs. Seamless connection with the impedance transformation stubs effectively feeds the odd-mode signal into the slot line. The second part ("|"-shaped) is designed as a vertical metal strip, vertically connected to the middle of the first part. When the stubs of the two branch ports are parallel, the three naturally form an "E"-shaped resonant unit. Its length directly affects the resonant frequency and isolation. Electromagnetic simulation software can be used to optimize its parameters. By adjusting this length, the resonant frequency of the resonant structure can be extended, and the port isolation can be improved.

[0052] Furthermore, according to the broadband design requirements, the initial parameter of the slot line circle radius is equal to the radius of the arc formed by the microstrip impedance transformation stub; to ensure high microstrip slot line coupling efficiency, the first structure in the resonant structure closes the impedance transformation stub, and the initial linewidth of the second structure is the same as the input and output microstrip line width; the initial width of the slot line is set to be the same as the input and output microstrip line width, and the initial length is equivalent to a quarter wavelength of the center frequency; to meet broadband isolation, the initial linewidth of the annular slot line is set to twice the microstrip linewidth, and the initial radius of the annular slot line is set to twice the radius of the arc formed by the slot line circle and the microstrip impedance transformation stub.

[0053] S103. Based on the bandwidth and isolation improvement targets and the amplitude and phase modulation requirements of odd-mode signals, design the initial layout of the defective ground structure, optimize the parameters of the initial layout, and obtain the Wilkinson power divider.

[0054] Specifically, the components of the defect structure are determined, including a circular slotted structure, a slotted structure, and a slotted annular structure, with the slotted structure connecting the circular and annular structures. Based on the odd-mode signal guidance path, the initial position of the circular slotted structure is set so that it is directly below the two impedance transformation stubs, and the center of the circular slotted structure maintains a specific distance from the center of the impedance transformation stubs. According to bandwidth requirements, the radius of the circular slotted structure is kept consistent with the radius of the impedance transformation structure. According to bandwidth and isolation requirements, the initial length and width of the slotted structure, as well as the initial diameter and width of the annular slotted structure, are set.

[0055] Furthermore, the defective ground structure consists of a circular slotted line, a slotted line, and a slotted line ring. The circular slotted line structure is responsible for expanding the operating bandwidth, the slotted line is used to receive electromagnetic signals fed in by the microstrip line, and the slotted line ring structure is responsible for transmitting odd-mode signals with equal amplitude and phase inversion, and superimposing and canceling them on the transmission path. This composition logic is verified through electromagnetic simulation to ensure the functional coordination of each component.

[0056] Furthermore, the circular slot lines, slot lines, and slot line rings are laid out and integrated according to the above design to ensure a smooth transition at the connection points between the slot lines and the circular and ring lines, avoiding losses and phase shifts caused by abrupt changes in current transmission. Through overall electromagnetic simulation verification, the relative positions and dimensional parameters of each component are adjusted to enable odd-mode signals to propagate effectively along the path of the defect, forming a 180° phase difference during propagation, ultimately canceling each other out, achieving efficient isolation between branch ports and meeting the isolation improvement target.

[0057] Furthermore, based on the bandwidth and isolation targets, simulation software such as CST and HFSS are used to gradually increase the line length of the second structure in the resonant structure to increase structural resonance and improve isolation. Simultaneously, the width and length of the slot line and the radius of the slot line circle are adjusted to expand the bandwidth; the width and radius of the slot line ring are adjusted to further improve the broadband isolation index; and the input and output linewidths and the line length and radius of the impedance transformation structure are fine-tuned to ensure that the input and output impedances are basically matched with the standard 50Ω characteristic impedance under broadband conditions. Moreover, optimization algorithms can be introduced throughout the design process to optimize multiple parameters simultaneously, shortening the design cycle. By optimizing the above parameters, equal-amplitude and in-phase power distribution and high isolation index at the output port can be achieved within the broadband range, resulting in the aforementioned de-resistance broadband Wilkinson power divider.

[0058] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A de-blocking broadband Wilkinson power divider, characterized in that, The power divider includes: a metal microstrip line structure, a dielectric substrate, and a defect ground structure; the metal microstrip line structure includes a shunt structure and a T-shaped resonant structure, and is located on the top layer of the power divider; the dielectric substrate is used to place the metal microstrip line structure and the defect ground structure, and is located below the metal microstrip line structure and above the defect ground structure; the defect ground structure includes a slot line structure, a slot line circle, and a slot line ring; the metal microstrip line structure and the defect ground structure constitute a microstrip-slot line hybrid transmission structure, which supports even-mode signal transmission. When even-mode is excited, the center surface of the microstrip-slot line hybrid structure is equivalent to a magnetic wall, the slot line structure is not excited, and the metal microstrip line structure transmits even-mode signals; when odd-mode is excited, the center surface of the microstrip-slot line hybrid structure is equivalent to an electric wall, the slot line structure is excited, and the electromagnetic field is split into two signals with equal amplitude and opposite phase after entering the defect ground structure. The two signals cancel each other out and are superimposed, achieving port isolation.

2. The power divider according to claim 1, characterized in that, The branch structure includes a signal input port, an impedance transformation stub, and two branch output ports, with the impedance transformation stub located between the signal input port and the two branch ports.

3. The power divider according to claim 1, characterized in that, The T-shaped resonant structure is located between the two branch output ports. The first structure of the T-shaped resonant structure is used to close the impedance transformation stub, and the second structure of the T-shaped resonant structure is parallel to the two branch output ports.

4. The power divider according to claim 1, characterized in that, The slotted structure is used to connect the slotted circle and the slotted ring. The slotted structure is excited during odd-mode excitation. After entering the slotted ring, the electromagnetic field is split into two signals. The two signals have equal amplitudes and opposite phases, achieving superposition and cancellation.

5. The power divider according to claim 2, characterized in that, The input port is used to input radio frequency electrical signals, and the two branch ports are used to output radio frequency electrical signals with equal amplitude and in phase.

6. The power divider according to claim 1, characterized in that, The dielectric substrate serves as an insulating support carrier, and the dielectric substrate, the metal microstrip line structure, and the defect ground structure enable impedance matching of the Wilkinson power divider.

7. The power divider according to claim 1, characterized in that, The metal microstrip line structure and the defective ground structure constitute a microstrip slot hybrid transmission structure; the slot end of the defective ground structure is a circular stub, and the operating bandwidth is improved by adjusting the slot width, length and circular radius of the slot; the structural resonance is adjusted by adjusting the line width and line length of the T-shaped resonant structure; the bandwidth and isolation are optimized by adjusting the slot width and the size of the slot ring.

8. A design method for a de-blocking broadband Wilkinson power divider, characterized in that, The method includes: designing the initial parameters of the microstrip line splitter structure according to the standard impedance and power distribution requirements of the RF system; designing the initial shape of the resonant structure according to the bandwidth adjustment and coupling requirements of the microstrip slot line odd-mode signal; designing the initial layout of the defective ground structure according to the bandwidth and isolation improvement targets and the amplitude and phase modulation requirements of the odd-mode signal; optimizing the parameters of the initial layout to obtain the Wilkinson power divider.

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