A fin-line circuit and space power combiner suitable for high-frequency broadband

Abstract

This invention discloses a finline circuit and a spatial power combiner suitable for high-frequency broadband applications, belonging to the field of microwave technology. The finline circuit includes: a PCB board; fins disposed in the middle portion of the PCB board; two ground vias arranged on the PCB board, with the two ground vias located on opposite sides of the fins; and two electromagnetic bandgap structures disposed on the PCB board, with the two electromagnetic bandgap structures located outside the two ground via arrangements. This invention avoids resonance points within the operating frequency band by placing ground via arrangements and electromagnetic bandgap structures on both sides of the fins, thereby preventing cavity resonance effects from affecting the fins.

Description

Technical Field

[0001] This invention relates to the field of microwave technology, and in particular to a finline circuit and a space power combiner suitable for high-frequency broadband applications. Background Technology

[0002] Fin wires, as a commonly used microwave circuit structure, are often implemented using PCBs and are generally used in rectangular waveguides to realize waveguide TE. 10 Mode conversion from TEM mode to microstrip TEM mode.

[0003] In practical engineering applications, fins implemented using PCBs cannot float within the waveguide cavity; the fins themselves must rely on a certain amount of redundancy for support. For example... Figure 1 and Figure 2 As shown, Figure 1 This describes the implementation of fins in practical engineering applications. Existing methods involve adding ground holes on both sides of the fin as redundancy, with grooves in the structural base shell to secure the fins. To prevent leakage, the structural top cover must be tightly pressed against the structural base shell. Figure 3 As shown, the groove depth and PCB thickness are products of two different materials processed using different techniques; therefore, the groove depth and thickness cannot be equal. Figure 4 As shown Figure 3 In the cross-section of AA', to ensure the closure of the upper and lower shells, the groove depth needs to be greater than the PCB thickness. The specific value depends on the CNC machining accuracy of the lower shell and the PCB manufacturer's machining accuracy for the PCB thickness. The groove depth must be greater than the PCB thickness to ensure the closure of the upper and lower shells, which will result in a gap between the redundant ground holes and the upper shell. This gap causes cavity resonance, and the minimum resonant frequency depends on the gap length. The greater the length, the lower the minimum resonant frequency. Higher operating frequencies result in larger operating bandwidths and require longer fins. This will cause the resonant frequency to fall within the band. Figure 5 As shown, when the minimum resonant frequency is lower than the upper limit of the operating frequency, the resonant frequency will fall into the band, causing the collapse of S21. The width of the gap is limited by the machining accuracy and cannot be eliminated. Therefore, as the operating frequency increases, the resonant effect of the gap cannot be ignored in high-frequency, high-bandwidth scenarios, and existing technologies will no longer be applicable. Summary of the Invention

[0004] In order to at least partially solve one of the technical problems existing in the prior art, the present invention aims to provide a finline circuit and a space power combiner suitable for high frequency broadband.

[0005] The technical solution adopted in this invention is:

[0006] A finned-wire circuit suitable for high-frequency broadband, comprising:

[0007] PCB board;

[0008] Fins are located in the middle part of the PCB board;

[0009] Two ground holes are arranged on the PCB board, and the two ground holes are respectively located on both sides of the fin line;

[0010] Two electromagnetic bandgap structures are disposed on the PCB board, and the two electromagnetic bandgap structures are respectively located on the outer side of the two ground hole arrangements.

[0011] Furthermore, the fin line structure can be a single-sided fin line structure, a double-sided fin line structure, or a counterpolar fin line structure.

[0012] Furthermore, the two holes have the same structure, and the length of the holes is greater than or equal to the length of the fin.

[0013] Furthermore, the arrangement of the ground holes consists of several columns of redundant ground holes, and the spacing between adjacent redundant ground holes is less than or equal to a preset distance.

[0014] Furthermore, the preset distance is 2-3 times the diameter of the redundant ground hole to ensure that the redundant ground hole effectively shields the electromagnetic field within the fin.

[0015] Furthermore, the distance between the redundant ground hole and the edge of the fin is less than a preset value.

[0016] Furthermore, the electromagnetic bandgap structure is composed of several rows of mushroom-shaped electromagnetic bandgap units.

[0017] Furthermore, the length of the mushroom-shaped electromagnetic bandgap unit is 0.8-1.2 times the length of the fin.

[0018] Another technical solution adopted in this invention is:

[0019] A space power combiner, comprising:

[0020] Several structural covers;

[0021] Several structural base shells, wherein the structural base shells are provided with grooves;

[0022] Several finned circuits, as described above, suitable for high-frequency broadband, are disposed on the groove.

[0023] Furthermore, the groove covers the ground hole arrangement and the electromagnetic bandgap structure on the PCB board, and the PCB board is bonded to the groove by a conductive adhesive material to fix the PCB board to the structural base.

[0024] The beneficial effects of this invention are: by setting ground hole arrangement and electromagnetic bandgap structure on both sides of the fin, this invention avoids the occurrence of resonance points in the operating frequency band, thereby avoiding the influence of cavity resonance effect on the fin. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following description is provided with accompanying drawings of the relevant technical solutions in the embodiments of the present invention or the prior art. It should be understood that the accompanying drawings described below are only for the purpose of clearly illustrating some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a side view of a fin structure in an existing engineering project;

[0027] Figure 2 This is a front view of a fin structure in an existing engineering project;

[0028] Figure 3 This is a three-dimensional schematic diagram of a space power combiner;

[0029] Figure 4 yes Figure 3 A schematic diagram of the AA' section;

[0030] Figure 5 This is a schematic diagram showing how the gap causes cavity resonance;

[0031] Figure 6 This is a schematic diagram of a fin wire circuit suitable for high-frequency broadband in an embodiment of the present invention;

[0032] Figure 7 This is a front view of a finline circuit suitable for high-frequency broadband in an embodiment of the present invention;

[0033] Figure 8 This is the Brillouin plot of CMT-EBG in an embodiment of the present invention;

[0034] Figure 9 These are simulation result diagrams from embodiments of the present invention;

[0035] Figure 10 This is the simulation result of S21 in the embodiment of the present invention;

[0036] Figure 11 This is a schematic diagram of the fin structure in an embodiment of the present invention. Detailed Implementation

[0037] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0038] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0039] In the description of this invention, "several" means one or more, "more than" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0040] Furthermore, in the description of this invention, unless otherwise stated, "multiple" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0041] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0042] like Figure 6 As shown, this embodiment provides a finned wire circuit suitable for high-frequency broadband, including:

[0043] PCB board;

[0044] Fins are located in the middle part of the PCB board;

[0045] Two ground holes are arranged on the PCB board, and the two ground holes are respectively located on both sides of the fin line;

[0046] Two electromagnetic bandgap structures are disposed on the PCB board, and the two electromagnetic bandgap structures are respectively located on the outer side of the two ground hole arrangements.

[0047] The principle block diagram of this embodiment is as follows: Figure 6 As shown, the fins are placed at the center of the printed circuit board (PCB). Redundant ground vias are located on both sides of the fins, and an electromagnetic bandgap (EBG) structure is present on one side of each of these redundant ground vias. Because the bottom shell of the structure has a groove for placing the fin PCB, the groove depth and PCB thickness are products of different materials and different processing techniques; therefore, the groove depth and thickness cannot be equal. To ensure the top cover and bottom shell of the structure close together, the groove depth needs to be greater than the PCB thickness. The specific value depends on the CNC machining accuracy of the bottom shell and the PCB manufacturer's machining accuracy for the PCB thickness. The groove depth being greater than the PCB thickness is intended to ensure the closure of the upper and lower shells of the structure. By setting ground vias and an electromagnetic bandgap structure on both sides of the fins, resonant points within the operating frequency band are avoided, thus preventing the cavity resonance effect from affecting the fins.

[0048] As a further optional implementation, the fin structure can be a single-sided fin structure, a double-sided fin structure, or a counterpolar fin structure. All three types of fins are implemented using a PCB. Figure 11 (a) in the diagram is a schematic diagram of the bilateral fin line structure. Figure 11 (b) is a schematic diagram of a unilateral fin line structure. Figure 11 (c) in the diagram is a schematic diagram of the polar fin structure.

[0049] As a further optional implementation, the two borehole arrangements have identical structures, and the length of the borehole arrangement is greater than or equal to the length of the fin. For example... Figure 6 and Figure 7 As shown, in this embodiment, the length of the borehole arrangement is equal to the length of the fin.

[0050] As a further optional implementation, the ground hole arrangement consists of several rows of redundant ground holes, with the spacing between adjacent redundant ground holes being less than or equal to a preset distance. The preset distance is 2-3 times the diameter of the redundant ground holes to ensure that the redundant ground holes effectively shield the electromagnetic field within the fins.

[0051] In this embodiment, two rows of single-column ground vias are used. The number of rows of ground vias mainly depends on whether the PCB can be effectively fixed after the ground vias are combined with conductive adhesive material. Since this application is for high-frequency applications, two rows of single-column ground vias are sufficient.

[0052] As a further optional implementation, the distance between the redundant ground hole and the edge of the fin is less than a preset value. The redundant ground hole is placed as close as possible to the edge of the fin, which helps to avoid the parasitic effects caused by the redundant portion between the ground hole and the fin.

[0053] See Figure 6 and Figure 7 As a further optional implementation, the electromagnetic bandgap structure is composed of several rows of mushroom-shaped electromagnetic bandgap units. The length of each mushroom-shaped electromagnetic bandgap unit is 0.8-1.2 times the length of the fin.

[0054] The EBG structure on the PCB should be selected to accommodate the gaps in the top cover of the structure within the EBG unit. In this embodiment, a mushroom-shaped electromagnetic bandgap structure (CMT-EBG) is chosen to implement the electromagnetic bandgap structure. The entire EBG structure is composed of a single column of CMT-EBG units. Theoretically, any number of columns of CMT-EBG structures can be used, but in actual engineering, to balance the size and meet the miniaturization requirements of the circuit, a single column of CMT-EBG, i.e., the minimum number of columns, is used in this embodiment. Since an integer multiple of the CMT-EBG unit length is not necessarily exactly equal to the fin length, the total length of the array should be as equal to the fin length as possible, but not necessarily equal to or greater than that length.

[0055] According to Bloch's theorem, the overall CMT-EBG structure exhibits nearly identical bandgap characteristics to its elemental components. The characteristics of the elemental components can be determined by observing their Brillouin plots at periodic boundaries, a process that can be solved using the characteristic modulus solver in simulation software. Figure 8 The diagram shows the Brillouin plot of the CMT-EBG unit in this embodiment, with a bandgap bandwidth of 35.5–83 GHz. The horizontal axis of the Brillouin plot is proportional to the phase constant, and the vertical axis is the frequency, with its slope proportional to the phase velocity. The horizontal axis, from 0 to 180 degrees, represents incident waves at various angles. When the slope is close to 0, the frequency selectivity can be considered to be cut off for incident waves at that frequency point at that incident angle. In the diagram, the group velocity of incident waves at the frequencies of 35.5 GHz and 83 GHz is 0 for all incident angles. Since there are no solutions within the 35.5–83 GHz range, this range is considered an electromagnetic bandgap, and 35.5 GHz and 83 GHz are the upper and lower cutoff frequencies of the electromagnetic bandgap, respectively, meaning there are no field solutions within this electromagnetic bandgap. The PCB containing the CMT-EBG array is assembled into the structural partition. Since the microstrip master mode on the RF PCB is TEM, and the microstrip cannot couple any mode out with the upper cover plate. Therefore, only the TEM mode exists within the structure, thus achieving the suppression effect of the resonant mode.

[0056] Because CMT-EBG provides a sufficiently wide bandgap, there are no resonant points in the operating frequency band of 35.5–83 GHz, meaning that cavity resonance effect does not affect the fins.

[0057] When a gap appears above the redundant ground via and the CMT-EBG, the bandgap suppression effect of the CMT-EBG in the 35.5-83GHz range prevents the presence of resonant modes that could affect the operating frequency band. In other words, the resonant frequency is not within the operating frequency band, thereby widening the application bandwidth of the fin at the high-frequency end. The following figure shows the simulation results of this embodiment. The presence of the CMT-EBG prevents the diffusion of resonant modes, ultimately making S21 smooth and without pits within the operating frequency band.

[0058] In summary, this application improves upon the shortcomings of existing technologies, fundamentally solving the problem that the cavity resonance effect of the slot in finned circuits reduces bandwidth, making them unsuitable for high-frequency, high-bandwidth systems. The application of CMT-EBG eliminates the influence of cavity resonance on finned circuits within their operating frequency band, thereby increasing the application frequency of such circuits. Figure 9 and Figure 10 As shown, the simulation results of the circuit applied in the V band show that, thanks to the suppression of the resonant mode by the CMT-EBG structure, the pits caused by the cavity resonance effect are eliminated, the S21 waveform is smooth, and the fin circuit obtains the large bandwidth it should have, thus solving the bandwidth problem in the high-frequency application of this circuit.

[0059] See Figure 3 Based on the aforementioned finline circuit suitable for high-frequency broadband, this embodiment also provides a spatial power combiner, comprising:

[0060] Several structural covers;

[0061] Several structural base shells, wherein the structural base shells are provided with grooves;

[0062] Several Figure 6 The finned circuit shown is suitable for high-frequency broadband and is disposed on the groove.

[0063] As a further optional implementation, the groove covers the ground hole arrangement and the electromagnetic bandgap structure on the PCB board, and the PCB board is bonded to the groove by a conductive adhesive material to fix the PCB board to the structural base.

[0064] The spatial power synthesizer of this embodiment has the same function as the aforementioned finline circuit suitable for high-frequency broadband, and therefore also has the corresponding beneficial effects.

[0065] In the foregoing description of this specification, references to terms such as "one embodiment," "another embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0066] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

[0067] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A finned-wire circuit suitable for high-frequency broadband, characterized in that, include: PCB board; Fins are located in the middle part of the PCB board; Two ground vias are arranged on the PCB board, and the two ground vias are respectively located on both sides of the fin line; each ground via arrangement consists of several rows of redundant ground vias; Two electromagnetic bandgap structures are disposed on the PCB board, and the two electromagnetic bandgap structures are respectively located on the outer side of the two ground hole arrangements; each electromagnetic bandgap structure is composed of several rows of mushroom-shaped electromagnetic bandgap units.

2. The fin wire circuit suitable for high-frequency broadband according to claim 1, characterized in that, The fin line structure can be a single-sided fin line structure, a double-sided fin line structure, or a counterpolar fin line structure.

3. A finned-wire circuit suitable for high-frequency broadband according to claim 1, characterized in that, The two pore arrangements have the same structure, and the length of the pore arrangement is greater than or equal to the length of the fin.

4. A finned-wire circuit suitable for high-frequency broadband according to claim 1, characterized in that, The spacing between adjacent redundant boreholes is less than or equal to a preset distance.

5. A finned-wire circuit suitable for high-frequency broadband according to claim 4, characterized in that, The preset distance is 2-3 times the diameter of the redundant ground hole to ensure that the redundant ground hole effectively shields the electromagnetic field inside the fin.

6. A finned-wire circuit suitable for high-frequency broadband according to claim 1, characterized in that, The distance between the redundant ground hole and the edge of the fin is less than a preset value.

7. A finned wire circuit suitable for high-frequency broadband according to claim 1, characterized in that, The length of the mushroom-shaped electromagnetic bandgap unit is 0.8-1.2 times the length of the fin.

8. A space power combiner, characterized in that, include: A structural cover; A structural base shell, wherein the structural base shell is provided with a groove; A finned circuit suitable for high-frequency broadband as described in any one of claims 1-7 is disposed on the groove.

9. A space power combiner according to claim 8, characterized in that, The groove covers the ground hole arrangement and the electromagnetic bandgap structure on the PCB board, and the PCB board is bonded to the groove by a conductive adhesive material to fix the PCB board to the bottom shell of the structure.

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