A dual-passband millimeter-wave filter power divider based on gap waveguide

Abstract

This invention belongs to the field of microwave passive device technology and discloses a dual-passband millimeter-wave filter power divider based on a gap waveguide, comprising a metal bottom cover layer and a metal top cover layer arranged from bottom to top; wherein, the metal top cover layer includes a top cover and a top cover frequency division structure disposed on the top cover; the metal bottom cover layer includes a bottom cover and a bottom cover frequency division structure, a filtering structure, and a power divider network structure disposed on the bottom cover. The dual-passband millimeter-wave filter power divider based on a gap waveguide provided by this invention solves the technical problems of existing dual-passband filter power dividers, such as high design optimization requirements, narrow dual-frequency bands, difficulty in flexibly changing frequency bands, and high processing requirements.

Description

Technical Field

[0001] This invention belongs to the field of microwave passive device technology, and specifically relates to a dual-passband millimeter-wave filter power divider based on a gap waveguide. Background Technology

[0002] Millimeter-wave technology is a key technology for the electronic systems supporting spacecraft. With the rapid development of aerospace technology and the official commercialization of fifth-generation mobile communication systems, space millimeter-wave technology is generally showing a trend of high power, high frequency, and high integration. Compared with microwave devices, millimeter-wave devices are much smaller in size, making them easier to miniaturize and integrate; however, millimeter waves also have the characteristics of weak penetration, high transmission loss, and susceptibility to environmental interference.

[0003] In communication systems, filters primarily function to remove unwanted frequency components and interference noise, reducing system sensitivity and improving interference immunity; power dividers primarily function to divide a single signal into multiple signals, thus distributing power evenly. In practice, filters and power dividers are usually used simultaneously, therefore, filter-power dividers that integrate filtering and power distribution have been extensively studied.

[0004] Traditional filter and power divider designs are primarily based on planar printed circuit board technology, which offers high design precision and small size. However, microstrip transmission lines suffer from high losses and low power capacity in the millimeter-wave band. In contrast, air-filled metal waveguide transmission line structures are widely used in the communications field due to their advantages of low loss, high power capacity, and high mechanical strength. Rectangular waveguide structures are simple and technologically mature; however, as frequencies increase and device dimensions decrease, the requirements for welding between metal walls during manufacturing become more stringent, significantly increasing the manufacturing cost of rectangular waveguides.

[0005] Gap waveguides consist of two metal plates and periodic electromagnetic band gaps on both sides, effectively preventing electromagnetic waves from radiating to both sides without requiring complete sealing, which greatly reduces manufacturing costs. Existing dual-frequency filters based on gap waveguides mainly consist of resonant-coupled dual-frequency filters obtained by coupling dual-mode / multi-mode resonant cavities. This design structure is simple, and the resonant coupling theory is relatively mature. However, its disadvantages include the fact that the coupling degree of different modes is usually different when dual-mode / multi-mode resonant cavities are coupled, which leads to high requirements for optimization during the design process. In addition, the resulting dual-frequency filters usually have a narrow bandwidth, and the frequency band is difficult to change according to different needs. Furthermore, due to the physical structure of the resonant cavity based on gap waveguides, it is not convenient to design corresponding power divider structures and integrate them. Summary of the Invention

[0006] The purpose of this invention is to provide a dual-passband millimeter-wave filter power divider based on a gap waveguide, in order to solve the technical problems of existing dual-passband filter power dividers, such as high design optimization requirements, narrow dual-frequency bands, difficulty in flexibly changing frequency bands, and high processing requirements.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a dual-passband millimeter-wave filter power divider based on a gap waveguide, comprising a metal bottom cover layer and a metal top cover layer arranged from bottom to top; wherein,

[0009] The metal top cover layer includes a top cover and a top cover frequency division structure disposed on the top cover; wherein, the top cover frequency division structure is a resonant structure composed of defective metal blocks;

[0010] The metal bottom cover layer includes a bottom cover and a bottom cover frequency division structure, a filter structure, and a power divider network structure disposed on the bottom cover; wherein, the bottom cover frequency division structure, the filter structure, and the power divider network structure are arranged sequentially along the direction of electromagnetic wave transmission, forming a T-shaped structure; the bottom cover frequency division structure is composed of rectangular walls, the top layer of which is used to fit with the top cover, accommodating the resonant structure in the rectangular waveguide formed by the rectangular walls, the top cover, and the bottom cover; the filter structure is composed of a slot gap waveguide structure and an artificial surface plasmon structure; the power divider network structure is a one-to-two in-phase power distribution network composed of slot gap waveguides.

[0011] A further improvement of the present invention is that,

[0012] The bottom cover frequency division structure is specifically composed of two rectangular walls, which are symmetrical about the center line of the T-shaped structure and are located at the input port at the bottom of the T-shaped structure.

[0013] A further improvement of the present invention is that,

[0014] The filtering structure is specifically composed of a slot gap waveguide structure formed by pin units set on the bottom cover and an artificial surface plasmon structure; wherein, each side of the pin unit is provided with n layers and is symmetrical about the center line of the T-shaped structure; the artificial surface plasmon structure is set on the center line of the T-shaped structure and is symmetrical about the center line of the T-shaped structure.

[0015] A further improvement of the present invention is that,

[0016] The slot gap waveguide structure includes a transition section structure and a straight waveguide structure. The transition section structure consists of the first m rows of pins viewed from the input port. The spacing between the pin units in each row is the same, and the width of the slot gap waveguide formed between each row of pins gradually decreases by an equal amount. The straight waveguide structure consists of pins located after the transition section structure. The spacing between the pin units in each row is the same, and the width of the slot gap waveguide formed between each row of pins remains constant.

[0017] A further improvement of the present invention is that,

[0018] All pin units are identical in shape and size.

[0019] A further improvement of the present invention is that,

[0020] The artificial surface plasmon structure includes a front transition section SSPP, a filter section SSPP, and a rear transition section SSPP; wherein the front transition section SSPP and the rear transition section SSPP are respectively disposed before and after the filter section SSPP; the front transition section SSPP and the rear transition section SSPP are respectively composed of a first preset number of SSPP units with successively increasing and decreasing heights, the height curves being approximately exponential functions and symmetrical about the filter section SSPP; the filter section SSPP is composed of a second preset number of SSPP units with fixed heights.

[0021] A further improvement of the present invention is that,

[0022] The thickness, width, and spacing of the SSPP units are all the same.

[0023] A further improvement of the present invention is that,

[0024] The power distribution network structure is specifically composed of a T-arm formed by a slot gap waveguide consisting of a tuning structure and pin units, forming an in-phase power distribution network; wherein, the two ports of the T-arm branch are output ports; the tuning structure is composed of a frustum and an inductive metal column, and the center point of the tuning structure is on the center line of the main arm of the T-arm and at a certain distance above the center line of the T-arm branch.

[0025] A further improvement of the present invention is that,

[0026] The top radius of the frustum is the same as the radius of the inductive metal column, and their center points coincide.

[0027] A further improvement of the present invention is that,

[0028] In the T-arm, a row of pins with respect to the adjustment structure is set on the center line of the main arm of the T-arm, and k rows of pins extend to each of the two branches of the T-arm; according to the width of the main arm of the T-arm, pin structures are set at the positions of the two branches of the T-arm aligned with the width of the main arm of the T-arm, and extend outward; wherein, in the branch of the T-arm, the first m rows of pins seen from the output port form a transition section, the spacing of each pin unit in each row of pins is the same, and the width of the slot gap waveguide formed between each row of pins gradually decreases by an equal amount.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The dual-passband millimeter-wave filter power divider based on gap waveguides provided by this invention employs a bottom-up metal bottom cover layer and a top metal cover layer. Electromagnetic waves first pass through a frequency division structure formed by the top and bottom metal cover layers, creating a stopband for frequency division. Then, they pass through a filtering structure formed by SSPP (Self-Slotted Polymer Port) and pin-type slot gap waveguides, achieving high and low frequency cutoff frequencies respectively. Finally, power distribution is achieved through a power divider network structure, ultimately realizing a well-performing dual-frequency filtering and power divider function. This invention uses an all-metal structure, featuring high power capacity and strong heat dissipation. Furthermore, the use of slot gap waveguides eliminates the need for interlayer welding, effectively reducing overall processing difficulty and assembly precision. In summary, this invention achieves wide-band filtering with flexible adjustment through the combination of SSPP and slot gap waveguides; dual-band filtering is achieved through a frequency division resonant structure; processing difficulty and assembly requirements are reduced through gap waveguide technology; the all-metal structure improves power capacity and enhances the heat dissipation capacity of the slot waveguides; and the filter power divider has a wide operating bandwidth and low return loss. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below; obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the three-dimensional structure of a dual-passband millimeter-wave filter power divider based on a gap waveguide in an embodiment of the present invention;

[0033] Figure 2 This is a top view schematic diagram of the metal bottom cover layer of a dual-passband millimeter-wave filter power divider based on a gap waveguide in an embodiment of the present invention.

[0034] Figure 3 This is a side view schematic diagram of the metal bottom cover layer of a dual-passband millimeter-wave filter power divider based on a gap waveguide in an embodiment of the present invention.

[0035] Figure 4 This is a front view schematic diagram of the metal top cover layer of a dual-passband millimeter-wave filter power divider based on a gap waveguide in an embodiment of the present invention.

[0036] Figure 5 This is a side view schematic diagram of the metal top cover layer of a dual-passband millimeter-wave filter power divider based on a gap waveguide in an embodiment of the present invention.

[0037] Figure 6 This is a schematic diagram of the scattering parameter curves of a dual-passband millimeter-wave filter power divider based on a gap waveguide in an embodiment of the present invention;

[0038] Figure 7 This is a schematic diagram of the output phase of a dual-passband millimeter-wave filter power divider based on a gap waveguide in an embodiment of the present invention;

[0039] In the diagram, 1 represents the metal bottom cover layer; 2 represents the metal top cover layer.

[0040] 11. Rectangular wall; 12. Slot gap waveguide structure; 13. Artificial surface plasmon structure; 14. Frustum; 15. Inductive metal column;

[0041] 121. First layer pin unit of transition section; 122. Second layer pin unit of transition section; 123. Third layer pin unit of transition section; 124. Fourth layer pin unit of transition section; 125. Pin unit of straight waveguide section; 126. Pin unit of power divider structure section; 127. Pin unit of adjustment structure.

[0042] 131. First SSPP unit of transition section; 132. Second SSPP unit of transition section; 133. Third SSPP unit of transition section; 134. Fourth SSPP unit of transition section; 135. Fifth SSPP unit of transition section; 136. Sixth SSPP unit of transition section;

[0043] 21. Defective metal block. Detailed Implementation

[0044] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0045] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0046] The present invention will now be described in further detail with reference to the accompanying drawings:

[0047] Please see Figures 1 to 5 This invention provides a dual-passband millimeter-wave filter power divider based on a gap waveguide, comprising a metal bottom cover layer 1 and a metal top cover layer 2 arranged from bottom to top; wherein,

[0048] The metal top cover layer 2 includes a top cover and a top cover frequency division structure disposed on the top cover; wherein, the top cover frequency division structure is a defect metal block resonant structure (coupling structure) composed of two defect metal blocks 21 on the same straight line, which plays the role of constructing a stopband to achieve frequency division;

[0049] The metal bottom cover layer 1 includes a bottom cover and a bottom cover frequency division structure, a filtering structure, and a power divider network structure disposed on the bottom cover. The bottom cover frequency division structure is composed of a rectangular wall 11, which confines the top cover frequency division structure on the metal top cover layer 2 within the rectangular wall 11 of the bottom cover frequency division structure. The filtering structure consists of a slot gap waveguide structure 12 and an artificial surface plasmon structure 13, serving to construct a bandpass filter. The power divider network structure is a one-to-two in-phase power distribution network composed of pin-type slot gap waveguides. More specifically, the bottom cover frequency division structure, filtering structure, and power divider network structure are fixedly disposed on the bottom cover.

[0050] In the technical solution of this invention embodiment, electromagnetic waves are fed in through the central input port, and first pass through a frequency division structure composed of the resonant structure of the metal top cover layer 2 and the rectangular wall 11 of the metal bottom cover layer 1 to achieve frequency division; then pass through a filtering structure to obtain a dual-passband filtering effect; and finally pass through a power divider network structure to achieve dual-passband filtering power division function.

[0051] In this embodiment of the invention, the bottom cover frequency division structure is composed of two rectangular walls 11, which are disposed at the input port of the metal bottom cover layer 1. The bottom cover can be a T-shaped structure, and the two rectangular walls 11 are symmetrical about the center line of the bottom cover. Explained, during assembly, the top of the rectangular wall 11 is attached to the top cover, and the resonant structure does not make electrical contact with the inner side of the rectangular wall 11. This means that the resonant structure is contained within the rectangular waveguide formed by the rectangular wall 11, the top cover, and the bottom cover. There is a certain distance between the defective metal blocks 21 in the resonant structure, which constitutes resonant coupling and forms a frequency division stopband. Further explained, the frequency division structure of the present invention adopts a combination assembly of the top cover frequency division structure and the bottom cover frequency division structure. Specifically, the resonant structure composed of the defective metal blocks 21 is completely contained within the rectangular wall 11. During electromagnetic wave transmission, the resonant electric field induced on the resonant structure is completely contained within the rectangular wall 11 and does not affect the subsequent gap waveguide, thereby improving matching performance and reducing in-band return loss. Furthermore, the resonant frequency can be adjusted by adjusting the size of the resonant structure and its distance from the center line, and the coupling degree can be adjusted by adjusting the spacing of the resonant structure of the defective metal block 21. Therefore, the technical solution of this embodiment can achieve flexible adjustment of the center frequency and bandwidth of the frequency division stopband, and the optimization requirements are relatively simple.

[0052] In this embodiment of the invention, the filtering structure is set after the bottom cover frequency division structure, and is composed of a slot gap waveguide structure 12 formed by pin units set on the bottom cover and an artificial surface plasmon structure 13 formed by SSPP units; specifically, the pin units are arranged in three layers on each side and are symmetrical about the center line of the bottom cover to prevent electromagnetic waves from propagating to both sides; the artificial surface plasmon structure 13 is set on the center line of the bottom cover and is symmetrical about the center line of the bottom cover.

[0053] In a further preferred embodiment of the present invention, the slot gap waveguide structure 12 is divided into a transition section structure and a straight waveguide structure; wherein, the transition section structure consists of the first four rows of pins viewed from the input port (specifically exemplified, such as...). Figure 2 , Figure 3 As shown, the filter structure comprises a first-layer pin unit 121, a second-layer pin unit 122, a third-layer pin unit 123, and a fourth-layer pin unit 124. The pin units in each row of pins have the same spacing, and the width of the slot gap waveguide formed between each row of pins gradually decreases by an equal amount, thereby improving the matching performance of the filter structure. The straight waveguide structure consists of straight waveguide pin units 125 placed after the transition section structure at the input port. The pin units in each row of pins in this section have the same spacing, and the width of the slot gap waveguide formed remains constant, thus limiting the low-frequency cutoff frequency of the filter structure. The low-frequency cutoff frequency of the filter structure can be adjusted by adjusting the width of the straight waveguide section. Further illustratively, the technical solution of this embodiment improves the matching performance at the port and reduces return loss by setting a transition structure at the port of the filter structure.

[0054] In this embodiment of the invention, the artificial surface plasmon structure 13 is divided into a transition section SSPP and a filter section SSPP; wherein, there is a section before and after the transition section SSPP, and each section consists of six SSPPs with successively increasing or decreasing heights (for specific examples, please refer to...). Figure 2 , Figure 3 The filter structure comprises six SSPP units (131, 132, 133, 134, 135, and 136) in a transition section. The height curve approximates an exponential function. A transition structure is provided at both ends and is symmetrical about the middle filter section SSPP to improve the matching performance of the filter structure. The filter section SSPP consists of five SSPP units of fixed height, used to limit the high-frequency cutoff frequency of the filter structure. In a further preferred embodiment of the invention, all SSPP units in the filter structure have the same thickness, width, and spacing. Further illustratively, embodiments of the present invention limit the high-frequency cutoff frequency of the power divider by using SSPP (Sectional Surface Mount Power Divider) and limit the low-frequency cutoff frequency of the power divider by using slot gap waveguides. The high-frequency cutoff frequency can be flexibly adjusted by adjusting the height, width, and spacing of the SSPP; the low-frequency cutoff frequency can be flexibly adjusted by adjusting the slot width of the slot gap waveguide. This method, combined with a frequency division structure, ultimately achieves flexible adjustment of the center frequency and bandwidth of the dual-band. This method can simultaneously achieve a large bandwidth for both bands and has low optimization requirements.

[0055] In this embodiment of the invention, the power divider network structure consists of a T-arm formed by slot gap waveguides composed of pin units and a matching structure, constituting an in-phase power distribution network. The power divider network structure is positioned after the filter structure, and the pin units 126 of the power divider structure segment of the T-arm main arm have the same width. In a further preferred embodiment, to maintain the symmetry of the overall structure, pins related to the matching structure are set on the central symmetry line of the T-arm, and three layers are set (explanatory, such as...). Figure 2A row of pin units 127, positioned on the centerline and directly opposite the matching structure, extends outwards to each of the two branches of the T-arm. This is to ensure electromagnetic wave leakage at the matching structure and maintain structural symmetry. Based on the width of the main arm of the T-arm, pin structures are also installed at the two branches, aligned with the width of the main arm. Three layers of these pin structures are also installed, extending outwards to maintain alignment between the pins on the main arm and branches of the T-arm power divider, facilitating manufacturing. In this embodiment, the matching structure consists of a frustum 14 and a section of inductive metal column 15, used to adjust the power divider network matching and reduce return loss. Preferably, the center point of the power divider structure is located on the centerline of the main arm of the T-arm, and above the centerline of the branch of the T-arm at a certain distance. By adjusting the distance from the centerline of the branch of the T-arm, the radius of the inductive metal column 15 and the bottom radius of the frustum 14, etc., the optimal power divider effect is achieved, making the power divider structure have a wider power divider bandwidth and lower in-band return loss. The upper radius of the frustum 14 is the same as the radius of the inductive metal column 15, and their center points are the same. Further illustratively, this embodiment of the invention uses a pin-type slot gap waveguide to form a T-arm power divider structure, and introduces the combination of the frustum 14 and the inductive metal column 15 for power divider structure adjustment. The combination of the inductive metal column 15 and the frustum 14 can achieve better impedance matching of the power divider structure, ultimately ensuring that the electromagnetic waves transmitted to the two ports have the same amplitude and phase. In the T-arm branch, the first m rows of pins, viewed from the output port, form a transition section. The spacing between the pin units in each row of pins is the same, and the width of the slot gap waveguide formed between each row of pins gradually decreases by an equal amount. The technical solution of this invention improves the matching performance at the port and reduces return loss by setting a transition structure at the port of the power divider structure.

[0056] In a further preferred embodiment of the present invention, the pins on the metal bottom cover layer 1 are all the same in shape and size. Except for the pins at the adjustment structure, the internal spacing of each row of pins is the same, and the spacing between rows is the same. The spacing between adjacent pins in the three layers of pins at the adjustment structure is the same, and the spacing is the same value.

[0057] In a further preferred embodiment of the present invention, the frequency division structure at the bottom of the metal top cover layer 2 is composed of two defective metal blocks 21 of identical size and shape. There is a certain distance between the center of the metal block and the center symmetry line of the top cover, and the right side of the defective metal block 21 does not contact the rectangular wall 11 of the bottom cover layer. The two defective metal blocks 21 are arranged in a straight line with a certain spacing to form a resonant coupling structure, thereby forming a stopband and realizing frequency division.

[0058] The present invention provides an explanatory principle of the dual-passband millimeter-wave filter power divider based on gap waveguides. In use, electromagnetic waves are fed in from the center port, pass through the frequency division, filtering and power division structure in sequence, and are finally output from the branch ports on both sides.

[0059] Specifically, firstly, the electromagnetic wave passes through the frequency division structure: during electromagnetic wave transmission, a time-varying electromagnetic field is loaded within the rectangular wall 11. At this time, the defective metal block 21 is affected by the time-varying electromagnetic field, generating an induced current. This induced current is blocked at the gap and can only pass through the gap as a displacement current, causing the gap to exhibit distributed capacitance characteristics. Simultaneously, the excited defective metal block 21 as a whole generates a self-inductance, thus effectively becoming a resonant circuit structure that resonates at a certain frequency. The intensity of the time-varying electromagnetic field varies depending on the distance of the defective metal block 21 from the centerline, thereby changing the equivalent distributed capacitance and self-inductance, resulting in resonance. The frequency also changes accordingly; different sizes of defective metal blocks 21 will also lead to different resonant frequencies; at this time, the defective metal block 21 is equivalent to a resonant structure. By setting the spacing between two identical defective metal blocks 21, the resonant structures can be coupled to each other, thereby forming a stopband for frequency division; therefore, by adjusting parameters such as the spacing, size and distance from the center line of the resonant metal blocks, the center frequency and bandwidth of the frequency division stopband can be flexibly adjusted; the rectangular wall 11 plays the role of completely confining the electric field during resonance, so as not to affect the subsequent structure; after the electromagnetic wave passes through the frequency division structure, it has been divided by the stopband. After passing through the frequency division structure, the electromagnetic wave first passes through a transition section formed by a pin-shaped slot gap waveguide. This transition section ensures impedance matching and reduces overall return loss. Following the transition section is a straight waveguide section with a constant slot width. Adjusting this slot width allows for adjustment of the low-frequency cutoff frequency of the filter structure. Simultaneously, an SSPP (Surface Plasmon Polarizing Polymer) structure is incorporated within the filter section, with a transition SSPP structure placed before and after it to ensure impedance matching. Under the induction of an external electromagnetic field, the free electrons on the metal surface of surface plasmons collectively resonate, forming surface waves along the metal and dielectric. These electromagnetic waves are confined to the vicinity of the interface, and the SSPP offers stronger field confinement and easier structural optimization. It exhibits low-pass properties, and by placing a SSPP section of uniform height in the middle, the high-frequency cutoff frequency is limited. The specific high-frequency cutoff frequency can be adjusted by modifying parameters such as height. After the stopband frequency division, the electromagnetic wave is split into two bands after passing through the filter section structure, achieving dual-passband filtering. The slot gap waveguide of the power divider adopts an H-plane T-shaped power divider structure. After passing through the H-plane T-shaped power divider structure, the electromagnetic wave is split into two segments with identical amplitude and phase, which are output through the ports. The H-plane T-shaped structure is simple to design, but it requires an impedance adjustment structure to be used; otherwise, it will suffer from high VSWR at the input port, extremely poor passband characteristics, and inability to transmit energy at the output port. The adjustment structure formed by the frustum 14 and the inductive metal pillar 15 can effectively adjust the T-junction. The frustum 14 structure is equivalent to a smooth impedance transformation structure, which plays a role in expanding the power divider bandwidth. Optimized, when the adjustment structure is offset from the centerline of the T-branch, the adjustment effect varies depending on the degree of offset. The best value is obtained through design optimization.Similarly, a transition gap waveguide structure is set at both output ports to ensure impedance matching at the ports.

[0060] In the technical solution provided by this invention, except for the use of a small rectangular structure for the frequency division band, all other layers adopt gap waveguide technology, which eliminates the need for strict electrical contact, effectively reducing losses and simplifying overall assembly. Frequency division is achieved using an all-metal resonant structure, and the division effect can be flexibly adjusted by modifying its parameters. The rectangular walls confine the resonant electric field within the structure, preventing interference with subsequent structures and effectively reducing return loss. The combination of slot gap waveguides and SSPPs achieves a wide-bandwidth bandpass filter with flexibly adjustable upper and lower sidebands. The slot gap waveguides form an H-plane T-shaped power divider structure to achieve equal-amplitude and in-phase power distribution, and the matching structure of the frustum and the metal inductive column ensures a wide power division bandwidth for the H-plane T-shaped structure. A gap waveguide transition structure is provided at each port to ensure impedance matching and reduce return loss. The all-metal structure improves the power capacity and mechanical strength of the dual-frequency filter power divider.

[0061] In a specific exemplary embodiment of the present invention, the electromagnetic wave feed port is a WR-34 standard waveguide port, with a width of 8.64 mm and a height of 4.32 mm; the thickness of both the top and bottom covers is 2 mm; the main arm portion is 23.14 mm wide; the rectangular wall is 10 mm long; the two defective metal blocks are identical and are combined with the top cover, with a length of 2.1 mm, a width of 0.9 mm, and a height of 2.02 mm, and the defective metal opening portion is 0.8 mm long, 0.9 mm wide, and 0.7 mm high, with the edge horizontally 3.5 mm away from the input port and the spacing being 2.8 mm; the distance between the centerline of the resonant structure and the centerline of the T-arm is 3.6 mm.

[0062] In specific exemplary embodiments of the present invention, all pin units are the same size, with a length and width of 1mm and a height of 4mm; the spacing between adjacent pin units within the filter structure is 2.5mm, and the horizontal distance between the edge of the first row of pin units and the rectangular wall is 1.25mm; the widths of the slot gap waveguides formed by the transition section pin units are 8.64mm, 8.44mm, 8.24mm, and 8.04mm respectively; the width of the slot gap waveguides formed by the straight waveguide section pin units is 8.04mm; the SSPP unit is 0.8mm long, 0.8mm wide, and spaced 2.5mm apart; the heights of the transition section SSPP units are 0.3mm, 0.6mm, 0.95mm, 1.2mm, 1.45mm, and 1.65mm respectively; and the height of the filter section SSPP unit is 1.75mm.

[0063] In specific exemplary embodiments of the present invention, the slot width of the waveguide formed by the pin units in the power distribution structure section is 7.84 mm, and the spacing between adjacent pin units is 2.5 mm; the spacing between adjacent pin units in the adjustment structure is 2.5 mm; the slot width of the waveguide formed by the pin units in the transition section is 8.64 mm, 8.44 mm, 8.24 mm, and 8.04 mm respectively; the distance between the frustum and the centerline of the T-arm branch offset from the inductive metal column is 0.8 mm; the lower base radius of the frustum is 2.72 mm, and the upper base radius and the radius of the inductive metal column are both 0.5 mm and 2.5 mm high; the inductive metal column is in contact with the lower base of the top cover.

[0064] Please see Figure 6 , Figure 6 The diagram below shows the simulation results of the scattering parameters of the dual-passband millimeter-wave filter power divider described in the embodiment; from Figure 6 It can be seen that at low frequencies, the -10dB impedance bandwidth is 21.2% (20.60GHz-25.50GHz), and the 3.25dB power divider bandwidth is 20.8% (20.64GHz-25.42GHz); from Figure 6 As can be seen, at high frequencies, the -10dB impedance bandwidth is 12.5% ​​(27.48GHz-31.14GHz), and the 3.25dB power divider bandwidth is 11.7% (27.62GHz-31.04GHz); from the attached... Figure 6 As can be seen, the in-band transmission coefficients between the two output ports remain at the same amplitude.

[0065] Please see Figure 7 , Figure 7 The diagram below shows the simulation results of the output phase of the dual-passband millimeter-wave filter power divider described in the embodiment; from Figure 7 As can be seen, the two output ports remain in phase.

[0066] In a specific and exemplary embodiment of the present invention, the dual-passband millimeter-wave filter power divider based on the gap waveguide can be mechanically processed by CNC milling of metal. The filter power divider has high mechanical strength and good mechanical performance. Generally, microwave devices in the millimeter-wave band mostly adopt an all-metal structure. However, during the assembly process, it is inevitable that the metal cannot be tightly attached due to welding, etc., resulting in air gaps and reduced efficiency. In the technical solution of the present invention, the gap waveguide structure forms an artificial magnetic conductor (AMC) structure through a periodic nail-like structure. By controlling the distance with the top surface of the metal surface, a relatively wide electromagnetic bandgap structure can be formed. Energy with frequencies within the bandgap cannot propagate. This structure can enable low-loss transmission of electromagnetic energy. In this embodiment of the invention, a single power divider can simultaneously perform dual-passband millimeter-wave filtering and power dividing functions, integrating the functions and reducing the complexity of the communication system. It possesses the characteristics of low loss, high efficiency, and high power capacity of an all-metal structure, while reducing the requirements for assembly precision and ideal electrical contact. The structural design allows for flexible adjustment of the frequency range, and the dual-band bandwidth and center frequency can be adjusted according to actual needs. At the same time, the dual-passband obtained by this method generally has a wider bandwidth, overcoming the narrow bandwidth disadvantage of traditional resonant cavity coupled dual-passband filters.

[0067] In summary, this invention discloses a dual-passband millimeter-wave filter power divider based on a gap waveguide, comprising a metal bottom cover layer and a metal top cover layer arranged sequentially from bottom to top; the metal top cover layer includes a metal top cover and a top cover frequency division structure; the metal bottom cover layer includes a metal bottom cover and a bottom cover frequency division structure, a filtering structure, and a power divider network structure. This invention features a wide dual-passband bandwidth that is flexibly adjustable, and low in-band return loss; the all-metal structure improves power capacity and the heat dissipation capability of the gap waveguide; and the use of gap waveguide technology reduces processing difficulty and assembly requirements.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A gap waveguide based dual passband millimeter wave filtering power divider, characterized by, It includes a metal bottom cover layer (1) and a metal top cover layer (2) arranged from bottom to top; wherein, The metal top cover layer (2) includes a top cover and a top cover frequency division structure disposed on the top cover; wherein, the top cover frequency division structure is a resonant structure composed of defective metal blocks (21); The metal bottom cover layer (1) includes a bottom cover and a bottom cover frequency division structure, a filter structure and a power divider network structure disposed on the bottom cover; wherein, the bottom cover frequency division structure, the filter structure and the power divider network structure are arranged sequentially along the direction of electromagnetic wave transmission and form a T-shaped structure; the bottom cover frequency division structure is composed of a rectangular wall (11), the top layer of the rectangular wall (11) is used to fit with the top cover and accommodate the resonant structure in the rectangular waveguide formed by the rectangular wall (11), the top cover and the bottom cover; the filter structure is composed of a slot gap waveguide structure (12) and an artificial surface plasmon structure (13); the power divider network structure is a one-to-two in-phase power distribution network composed of slot gap waveguides; in, The bottom cover frequency division structure is specifically composed of two rectangular walls (11). The two rectangular walls (11) are symmetrical about the center line of the T-shaped structure and are located at the input port at the bottom of the T-shaped structure. The filtering structure is specifically composed of a slot gap waveguide structure (12) formed by pin units set on the bottom cover and an artificial surface plasmon structure (13); wherein, each side of the pin unit is provided with n layers and is symmetrical about the center line of the T-shaped structure; the artificial surface plasmon structure (13) is set on the center line of the T-shaped structure and is symmetrical about the center line of the T-shaped structure. The artificial surface plasmon structure (13) includes a front transition section SSPP, a filter section SSPP, and a rear transition section SSPP; wherein the front transition section SSPP and the rear transition section SSPP are respectively disposed before and after the filter section SSPP; the front transition section SSPP and the rear transition section SSPP are respectively composed of a first preset number of SSPP units with successively increasing and decreasing heights, the height curves are approximately exponential functions, and are symmetrical about the filter section SSPP; the filter section SSPP is composed of a second preset number of SSPP units with fixed heights; The power distribution network structure is specifically composed of a T-arm formed by a slot gap waveguide consisting of a tuning structure and a pin unit, forming an in-phase power distribution network; wherein, the two ports of the T-arm branch are output ports; the tuning structure is composed of a frustum (14) and an inductive metal column (15), and the center point of the tuning structure is on the center line of the main arm of the T-arm and at a certain distance above the center line of the T-arm branch.

2. The dual-passband millimeter-wave filter power divider based on a gap waveguide according to claim 1, characterized in that, The slot gap waveguide structure (12) includes a transition section structure and a straight waveguide structure; wherein, the transition section structure is composed of the first m rows of pins viewed from the input port, the spacing between each pin unit in each row of pins is the same, and the width of the slot gap waveguide formed between each row of pins gradually decreases by an equal amount; the straight waveguide structure is composed of pins set after the transition section structure, the spacing between each pin unit in each row of pins is the same, and the width of the slot gap waveguide formed between each row of pins remains unchanged.

3. The gap-waveguide based dual-passband millimeter-wave filtered power divider of claim 2, wherein, All pin units are identical in shape and size.

4. The gap-waveguide based dual-passband millimeter-wave filtering power divider of claim 1, wherein, The thickness, width, and spacing of the SSPP units are all the same.

5. The gap-waveguide based dual-passband millimeter-wave filtering power divider of claim 1, wherein, The top radius of the frustum (14) is the same as the radius of the inductive metal column (15), and their center points coincide.

6. A dual-passband millimeter-wave filter power divider based on a gap waveguide according to claim 1, characterized in that, In the T-arm, a row of pins with respect to the adjustment structure is set on the center line of the main arm of the T-arm, and k rows of pins extend to each of the two branches of the T-arm; according to the width of the main arm of the T-arm, pin structures are set at the positions of the two branches of the T-arm aligned with the width of the main arm of the T-arm, and extend outward; wherein, in the branch of the T-arm, the first m rows of pins seen from the output port form a transition section, the spacing of each pin unit in each row of pins is the same, and the width of the slot gap waveguide formed between each row of pins gradually decreases by an equal amount.

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