A three-way dual-passband filtering power divider

Abstract

This invention discloses a three-channel dual-passband filter power divider, comprising three stacked metal layers and a dielectric substrate. The dielectric substrate contains four isosceles right-angled triangular substrate integrated waveguide resonant cavities enclosed by metallized vias. First and second resonant cavities of the same size are connected by their right-angled sides to form a first triangular unit; third and fourth resonant cavities of the same size but larger are also connected by their right-angled sides to form a second triangular unit, with the hypotenuses of the two units adjacent. By setting coupling windows between specific cavities and metallized via isolation walls between the third and fourth cavities, the first and second cavities collaboratively generate a first passband, and the third and fourth cavities collaboratively generate a second passband. The input port is located on the right-angled side of the first cavity, and the three output ports are located on the right-angled side of the second cavity, with isolation resistors connecting the ports. This invention highly integrates dual-passband filtering and three-channel power division functions, offering advantages such as compact structure, low insertion loss, and good output consistency.

Description

Technical Field

[0001] This invention relates to the field of microwave passive device technology, specifically to a three-channel dual-passband filter power divider. Background Technology

[0002] In modern wireless communication systems, such as Wi-Fi 6E / 7 and 5G, devices often need to operate simultaneously on multiple separate frequency bands. Therefore, the RF front-end needs to be able to distribute a single signal to multiple channels and perform multi-band selection for the signal in each channel. Traditional solutions use a cascaded dual-passband filter and a three-way power divider, but this approach suffers from problems such as large size, high insertion loss, and difficulty in ensuring consistency across channels, failing to meet the urgent demands of modern communication equipment for high integration and high performance.

[0003] As a functionally integrated device, the power divider filter has become an effective way to solve the above problems. Among them, the design based on substrate integrated waveguide (SIW) technology has been widely studied due to its advantages such as low loss, high power capacity, and easy integration. However, existing SIW power divider designs often have complex structures and limited design freedom when realizing the combined functions of dual-passband filtering and three-way equal-amplitude in-phase power division, or it is difficult to ensure good passband performance and port isolation in a compact size.

[0004] Therefore, there is an urgent need for a novel, ingeniously designed, and easily manufactured three-way dual-passband filter power divider to efficiently achieve the above functions within a single planar structure, thereby improving the performance and integration of the RF front end. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a compact, high-performance, and easy-to-manufacture three-channel dual-passband filter power divider. This device achieves dual-passband filtering and three-channel equal-amplitude, in-phase power distribution simultaneously within a single device through a specific combination and connection of two sets of isosceles right-angled triangular SIW resonant cavities of different sizes.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A three-way dual-passband filter power divider includes an upper metal surface, a middle dielectric substrate and a lower metal surface stacked together. The middle dielectric substrate has four substrate integrated waveguide resonant cavities surrounded by metallized vias.

[0008] The four substrate integrated waveguide resonant cavities include a first substrate integrated waveguide resonant cavity, a second substrate integrated waveguide resonant cavity, a third substrate integrated waveguide resonant cavity, and a fourth substrate integrated waveguide resonant cavity; wherein, the first substrate integrated waveguide resonant cavity and the second substrate integrated waveguide resonant cavity have the same size, the third substrate integrated waveguide resonant cavity and the fourth substrate integrated waveguide resonant cavity have the same size, and the third substrate integrated waveguide resonant cavity has a larger size than the first substrate integrated waveguide resonant cavity and the second substrate integrated waveguide resonant cavity;

[0009] The four substrate integrated waveguide resonant cavities are connected through coupling windows and metallized via isolation structures, so that the first substrate integrated waveguide resonant cavity and the second substrate integrated waveguide resonant cavity work together to form a first filter passband, and the third substrate integrated waveguide resonant cavity and the fourth substrate integrated waveguide resonant cavity work together to form a second filter passband.

[0010] An input port is provided on the first substrate integrated waveguide resonant cavity;

[0011] A first output port, a second output port, and a third output port are provided on the second substrate integrated waveguide resonant cavity;

[0012] Isolation resistors are connected between each of the first output port, the second output port, and the third output port.

[0013] Furthermore, the right-angled side of the first substrate integrated waveguide resonant cavity is connected to the right-angled side of the second substrate integrated waveguide resonant cavity, and the right-angled side of the third substrate integrated waveguide resonant cavity is connected to the right-angled side of the fourth substrate integrated waveguide resonant cavity, each forming two isosceles right-angled triangular units, and the hypotenuses of the two isosceles right-angled triangular units are connected to each other.

[0014] Furthermore, coupling windows are provided between the first substrate integrated waveguide resonator and the second substrate integrated waveguide resonator, between the first substrate integrated waveguide resonator and the third substrate integrated waveguide resonator, and between the second substrate integrated waveguide resonator and the fourth substrate integrated waveguide resonator; the third substrate integrated waveguide resonator and the fourth substrate integrated waveguide resonator are electromagnetically isolated by densely arranged metallized vias, and no coupling window is provided.

[0015] Furthermore, the electromagnetic field modes excited in all of the aforementioned substrate-integrated waveguide resonant cavities are half-TE. 101 mold.

[0016] Furthermore, the input port is vertically positioned at the center of a right-angled side of the first substrate integrated waveguide resonant cavity; the first output port, the second output port, and the third output port are vertically positioned on a right-angled side of the second substrate integrated waveguide resonant cavity.

[0017] Furthermore, the input port is fed with a signal via an input microstrip line, and an input slot extending into the cavity is provided at the connection between the input microstrip line and the first substrate integrated waveguide resonant cavity; the first output port, the second output port, and the third output port are respectively connected to the second substrate integrated waveguide resonant cavity via output microstrip lines, and output slots extending into the cavity are respectively provided at the connection.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. High Functional Integration and Structural Innovation: Successfully integrates dual-passband filtering and three-way power distribution functions into a compact planar structure containing only four resonant cavities. Through the innovative combination of "large and small cavity pairs" (the first substrate integrated waveguide resonant cavity and the second substrate integrated waveguide resonant cavity form one pair, and the third substrate integrated waveguide resonant cavity and the fourth substrate integrated waveguide resonant cavity form another pair), and by utilizing their size difference to directly determine the center frequency of the two passbands, the design principle is clear and the structure is simple.

[0020] 2. Excellent performance and high consistency: Based on SIW technology, it has low intrinsic loss. The input port is located in the integrated waveguide resonator of the first substrate, and the three output ports are concentrated in the integrated waveguide resonator of the second substrate. This symmetrical feeding and power extraction method, combined with the isolation resistor between the output ports, ensures that the three output channels have good amplitude consistency, phase consistency and port isolation in both passbands.

[0021] 3. Compact layout and simple processing: All resonant cavities are isosceles right triangles, formed by cascading the right-angled sides and hypotenuses to create a neat layout that effectively utilizes the circuit board area. The entire structure can be fabricated in one go using standard PCB technology. All metallized vias, coupling windows, and fine slots can be implemented simultaneously, with mature technology and controllable costs.

[0022] 4. Clear coupling path and flexible design: By carefully arranging coupling windows and isolating them with metallized vias, the energy coupling path is clearly defined, allowing the bandwidth, out-of-band suppression, and other characteristics of the two passbands to be independently and flexibly controlled by adjusting the size of the coupling window, the size of the resonant cavity, and the parameters of the input and output slots. Attached Figure Description

[0023] Figure 1 This is a three-dimensional structural schematic diagram of the three-way dual-passband filter power divider of the present invention.

[0024] Figure 2 This is a top-view planar structural diagram of the three-channel dual-passband filter power divider of the present invention.

[0025] Explanation of the labels in the diagram:

[0026] 1-Upper metal surface, 2-Middle dielectric substrate, 3-Lower metal surface, 4-Metallized via, 5-Substrate integrated waveguide resonator, 51-First substrate integrated waveguide resonator, 52-Second substrate integrated waveguide resonator, 53-Third substrate integrated waveguide resonator, 54-Fourth substrate integrated waveguide resonator, 6-Coupled window, 7-Input port, 81-First output port, 82-Second output port, 83-Third output port, 9-Isolation resistor, 55-Input slot, 56-Output slot. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0028] Please see Figure 1 and Figure 2 This embodiment provides a three-channel dual-passband filter power divider, fabricated using standard multilayer printed circuit board (PCB) technology, with a three-layer structure. From top to bottom, it consists of: an upper metal surface 1, a middle dielectric substrate 2, and a lower metal surface 3. The upper metal surface 1 and the lower metal surface 3 are complete copper-clad metal layers, together forming the electromagnetic shielding ground plane. The middle dielectric substrate 2 is made of a dielectric material with a uniform dielectric constant (such as Rogers RO4350B), and the required resonant cavity structure is enclosed within it by an array of metallized vias 4.

[0029] Resonant cavity structure and layout: as shown in the appendix Figure 2 As shown, the core of this invention consists of four substrate integrated waveguide resonant cavities 5, namely, a first substrate integrated waveguide resonant cavity 51, a second substrate integrated waveguide resonant cavity 52, a third substrate integrated waveguide resonant cavity 53, and a fourth substrate integrated waveguide resonant cavity 54. The planar shape of these four cavities is an isosceles right triangle. Specifically, the first substrate integrated waveguide resonant cavity 51 and the second substrate integrated waveguide resonant cavity 52 have identical dimensions (let the length of the right angle be L1); the third substrate integrated waveguide resonant cavity 53 and the fourth substrate integrated waveguide resonant cavity 54 have identical dimensions, and their right angle length L2 is greater than L1 (L2 > L1). This dimensional difference is the physical basis for generating two passbands with different center frequencies.

[0030] The connections between these cavities are as follows: One right-angled side of the first substrate integrated waveguide resonant cavity 51 and one right-angled side of the second substrate integrated waveguide resonant cavity 52 are connected side-by-side through a metallized via 4, forming a larger isosceles right-angled triangular unit (which can be considered as virtual cavity A). Similarly, the third substrate integrated waveguide resonant cavity 53 and the fourth substrate integrated waveguide resonant cavity 54 are also connected through their right-angled sides, forming another larger isosceles right-angled triangular unit (virtual cavity B). Subsequently, the hypotenuse of virtual cavity A and the hypotenuse of virtual cavity B share a common side, and energy coupling and distribution between the two units are achieved through a specific coupling window 6 and isolation structure.

[0031] Coupling and Isolation Design: To achieve dual-passband response and control the coupling path, coupling windows 6 are provided at the following locations: the center of the right-angled sides of the first substrate integrated waveguide resonator 51 and the second substrate integrated waveguide resonator 52; and in the region adjacent to the hypotenuses of virtual cavity A and virtual cavity B, specifically between the first substrate integrated waveguide resonator 51 and the third substrate integrated waveguide resonator 53, and between the second substrate integrated waveguide resonator 52 and the fourth substrate integrated waveguide resonator 54. However, between the third substrate integrated waveguide resonator 53 and the fourth substrate integrated waveguide resonator 54, this application uses densely arranged metallized vias 4 (the via spacing is less than a certain multiple of the via diameter to satisfy the electric wall condition) for direct connection, thereby forming an electromagnetic isolation wall, and coupling windows 6 are not provided here. This design prevents direct energy coupling between the third substrate integrated waveguide resonator 53 and the fourth substrate integrated waveguide resonator 54, forcing energy to be transferred and redistributed through the first substrate integrated waveguide resonator 51 and the second substrate integrated waveguide resonator 52. This is crucial for achieving three-way power splitting. All excitations within the resonators operate in a "half-TE" mode. 101 The electric field is strongest at the center of the hypotenuse of the isosceles right-angled triangular cavity.

[0032] Port and Feed Structure: Input port 7 is vertically positioned at the center of a right-angled side of the first substrate integrated waveguide resonant cavity 51. It introduces a signal from the edge of the intermediate dielectric substrate 2 via an input microstrip line with a characteristic impedance of 50 ohms. To achieve good impedance matching, an input slot 55 extending into the cavity is etched at the connection point between the input microstrip line and the cavity wall of the first substrate integrated waveguide resonant cavity 51. Adjusting the depth and width of the input slot 55 allows for precise control of the external quality factor at the input end and optimization of return loss within the passband.

[0033] The first output port 81, the second output port 82, and the third output port 83 are vertically positioned on a right-angled side of the second substrate integrated waveguide resonant cavity 52. ​​They are connected to the edge of the middle dielectric substrate 2 via three output microstrip lines with a characteristic impedance of 50 ohms. At the connection point between each output microstrip line and the cavity wall of the second substrate integrated waveguide resonant cavity 52, an output slot 56 extending into the cavity is etched. By independently adjusting the size of each output slot 56, the coupling of each output port can be finely adjusted to ensure the balance of the three output signal amplitudes. An isolation resistor 9 is connected between each pair of the microstrip lines of the first output port 81, the second output port 82, and the third output port 83. The isolation resistor 9 is typically a surface-mount resistor, soldered to the upper metal surface 1, used to absorb reflected signals between the output ports, significantly improving the isolation between the output ports and ensuring the stability of the power divider under varying multi-port loads.

[0034] Working principle: Combining Figure 1 and Figure 2 The working principle of this invention is as follows: The radio frequency signal is fed in from the input port 7, coupled into the first substrate integrated waveguide resonant cavity 51 through the input microstrip line structure, and excites half of the TE signal. 101 The energy is then transferred through the preset coupling window 6 in the resonant cavity network.

[0035] Specifically, energy originates from the first substrate integrated waveguide resonator 51 and propagates primarily along two paths: one path directly couples to the second substrate integrated waveguide resonator 52 through the coupling window 6 between the first and second substrate integrated waveguide resonators 51; the other path couples to the third substrate integrated waveguide resonator 53 through the coupling window 6 between the first and third substrate integrated waveguide resonators 51. Furthermore, a coupling window 6 is also provided between the second and fourth substrate integrated waveguide resonators 52 and 54, allowing energy to be transferred between them.

[0036] Dual passband formation mechanism: The first substrate integrated waveguide resonant cavity 51 and the second substrate integrated waveguide resonant cavity 52 are the same size. They are strongly coupled through the coupling window 6 between them and resonate in synergy. Due to their small size, they form the first filter passband at a higher frequency.

[0037] The third substrate integrated waveguide resonator 53 and the fourth substrate integrated waveguide resonator 54 are the same size but larger. Although there is no direct coupling window between them (they are isolated by dense metallized vias 4), they form a cross-coupling loop through the two parallel coupling paths mentioned above ("from the first substrate integrated waveguide resonator 51 to the third substrate integrated waveguide resonator 53" and "from the second substrate integrated waveguide resonator 5 to the fourth substrate integrated waveguide resonator 54"). These two large resonators work together through this cross-coupling mechanism, forming a second filter passband at a lower frequency due to their larger size.

[0038] The three-way power divider works as follows: At the two passband frequencies mentioned above, the energy is effectively converged into the second substrate integrated waveguide resonator 52. Subsequently, the energy converged in the second substrate integrated waveguide resonator 52 is coupled to the connected output microstrip lines, thus outputting equal amplitude and in phase to the first output port 81, the second output port 82, and the third output port 83, completing the three-way power distribution function. Isolation resistors 9 connected between the output ports absorb reflected signals between the ports, thereby significantly improving the isolation between the output ports and ensuring the stability of the power divider under varying multi-port loads.

[0039] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A three-channel dual-passband filter power divider, characterized in that, It includes an upper metal surface (1), a middle dielectric substrate (2) and a lower metal surface (3) stacked together. The middle dielectric substrate (2) is provided with four substrate integrated waveguide resonant cavities (5) surrounded by metallized vias (4). The four substrate integrated waveguide resonant cavities (5) include a first substrate integrated waveguide resonant cavity (51), a second substrate integrated waveguide resonant cavity (52), a third substrate integrated waveguide resonant cavity (53), and a fourth substrate integrated waveguide resonant cavity (54); wherein, the first substrate integrated waveguide resonant cavity (51) and the second substrate integrated waveguide resonant cavity (52) have the same size, the third substrate integrated waveguide resonant cavity (53) and the fourth substrate integrated waveguide resonant cavity (54) have the same size, and are larger than the size of the first substrate integrated waveguide resonant cavity (51) and the second substrate integrated waveguide resonant cavity (52); The four substrate integrated waveguide resonators (5) are connected by a coupling window (6) and a metallized via (4) isolation structure, so that the first substrate integrated waveguide resonator (51) and the second substrate integrated waveguide resonator (52) work together to form a first filter passband, and the third substrate integrated waveguide resonator (53) and the fourth substrate integrated waveguide resonator (54) work together to form a second filter passband; An input port (7) is provided on the first substrate integrated waveguide resonant cavity (51); A first output port (81), a second output port (82), and a third output port (83) are provided on the second substrate integrated waveguide resonant cavity (52). Isolation resistors (9) are connected between the first output port (81), the second output port (82), and the third output port (83).

2. A three-channel dual-passband filter power divider according to claim 1, characterized in that, The right-angled side of the first substrate integrated waveguide resonator (51) is connected to the right-angled side of the second substrate integrated waveguide resonator (52), and the right-angled side of the third substrate integrated waveguide resonator (53) is connected to the right-angled side of the fourth substrate integrated waveguide resonator (54), each forming two isosceles right-angled triangle units, and the hypotenuses of the two isosceles right-angled triangle units are connected to each other.

3. A three-channel dual-passband filter power divider according to claim 2, characterized in that, The coupling window (6) is provided between the first substrate integrated waveguide resonator (51) and the second substrate integrated waveguide resonator (52), between the first substrate integrated waveguide resonator (51) and the third substrate integrated waveguide resonator (53), and between the second substrate integrated waveguide resonator (52) and the fourth substrate integrated waveguide resonator (54). The third substrate integrated waveguide resonator (53) and the fourth substrate integrated waveguide resonator (54) are electromagnetically isolated by densely arranged metallized vias (4), and no coupling window is provided.

4. A three-channel dual-passband filter power divider according to claim 1, characterized in that, The electromagnetic field mode excited in all the substrate integrated waveguide resonant cavities (5) is half TE. 101 mold.

5. A three-channel dual-passband filter power divider according to claim 1, characterized in that, The input port (7) is vertically positioned at the center of a right-angled side of the first substrate integrated waveguide resonant cavity (51); the first output port (81), the second output port (82) and the third output port (83) are vertically positioned on a right-angled side of the second substrate integrated waveguide resonant cavity (52).

6. A three-channel dual-passband filter power divider according to claim 5, characterized in that, The input port (7) is fed with a signal through an input microstrip line, and an input slot (55) extending into the cavity is provided at the connection between the input microstrip line and the first substrate integrated waveguide resonant cavity (51); the first output port (81), the second output port (82) and the third output port (83) are respectively connected to the second substrate integrated waveguide resonant cavity (52) through output microstrip lines, and an output slot (56) extending into the cavity is provided at the connection.

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