A band-stop filter based on a printed ridge gap waveguide

Abstract

The present invention discloses a band-stop filter based on a printed ridge gap waveguide, comprising: a bottom dielectric substrate; periodic mushroom units; a metal top plate; a microstrip transmission line placed on the upper surface of the bottom dielectric substrate; on both sides of the feeding network, the periodic mushroom units are uniformly arranged, with M columns on each side in the wide side direction of the dielectric substrate and N rows in the long side direction, where M and N are integers, and M≥2, N≥5. The energy in the band-stop filter of the present invention is transmitted in the air gap, so it can effectively reduce dielectric loss and improve transmission efficiency, especially in the millimeter-wave band, and has a simple structure and low processing difficulty, which is conducive to realizing the miniaturization and high-efficiency design of millimeter-wave systems.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency and microwave technologies, and particularly to a band-stop filter based on a printed ridge gap waveguide. Background Art

[0002] As an important electronic device or circuit, a filter plays a crucial role in electronic signal processing and communication systems. During signal transmission, signals are often affected by various noises and interferences, which can seriously reduce the quality and accuracy of the signals. The filter improves the signal quality by selectively filtering out these noise and interference signals. For example, in a radio communication system, the filter can filter out interference signals in different frequency bands, thereby improving the communication quality and reliability. In radar and radio systems, the filter is used for tasks such as suppressing spurious signals and filtering out interferences, which helps to improve the signal resolution and reliability and ensure the normal operation of the system.

[0003] In the related art, during the transmission of the microstrip gap waveguide, due to the influence of structural characteristics and dielectric materials, certain electromagnetic energy losses will occur. Such losses will not only reduce the signal transmission efficiency but may also affect the overall performance of the system. Or the gap waveguide with a metal structure has a relatively large overall weight because it uses all-metal or metal as the main constituent material, which is not conducive to high-density integration and miniaturization design. Therefore, a band-stop filter that can solve both the loss problem and is miniaturized and easy to integrate is needed to better be applied in various fields. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to some extent. To this end, the first object of the present invention is to propose a band-stop filter based on a printed ridge gap waveguide.

[0005] To achieve the above object, a band-stop filter based on a printed ridge gap waveguide according to the first aspect embodiment of the present invention includes: a substrate; a metal bottom plate, the metal bottom plate being attached to the lower surface of the substrate; a plurality of pads, the plurality of pads being attached to the upper surface of the substrate; metal columns, the metal columns connecting the plurality of pads to the metal bottom plate; a metal top plate, the metal top plate being disposed parallel to the plurality of pads at a preset distance directly above; a feeding portion, the feeding portion using a printed ridge gap waveguide for feeding, the feeding portion being a metal microstrip line, the metal microstrip line dividing the plurality of pads into two equal parts on average, the plurality of pads having M columns on each of the left and right sides along the wide side direction of the substrate, N rows along the long side direction of the substrate, and being arranged on both sides of the metal microstrip line at a preset period, the metal microstrip line being connected to the metal bottom plate through the metal columns, where M and N are integers, and M≥2, N≥5.

[0006] The band-stop filter based on a printed ridge gap waveguide according to an embodiment of the present invention forms an equivalent ideal magnetic conductor through the periodic combination of a substrate, a metal bottom plate, pads, and metal posts. The metal top plate is an ideal electric conductor. The two conductors are placed in parallel without contact, thus forming an electromagnetic bandgap structure. Electromagnetic waves are confined in the region between the electric conductor and the magnetic conductor and can only propagate along the metal ridge, that is, the electromagnetic waves propagate in the air gap between the metal top plate and the metal microstrip line. Therefore, this band-stop filter can enable energy or electromagnetic waves to be transmitted in the air gap between a PEC (Perfect Electrical Conductor) and a PMC (Perfect Magnetic Conductor). This propagation mode can reduce dielectric loss and improve transmission efficiency, which is more significant in the millimeter-wave band or even in the terahertz band. Moreover, the structure is simple and the processing difficulty is low, which is conducive to the miniaturization and high-density integration of the system.

[0007] In addition, the band-stop filter based on a printed ridge gap waveguide according to the above embodiment of the present invention may further have the following additional technical features:

[0008] According to an embodiment of the present invention, the substrate is rectangular, and the thickness of the substrate is 0.8 - 1.2 mm.

[0009] According to an embodiment of the present invention, the material of the substrate is a ceramic-filled reinforcing material, and the relative dielectric constant of the ceramic-filled reinforcing material is 3 and the relative permeability is 1.

[0010] According to an embodiment of the present invention, the length and width dimensions of the metal bottom plate and the metal top plate are the same as those of the substrate, the height of the metal post is the same as the thickness of the substrate, and the length of the metal microstrip line is the same as the length of the substrate.

[0011] According to an embodiment of the present invention, the materials of the metal bottom plate, the metal top plate, the pads, the metal posts, and the metal microstrip line are all copper, silver, or gold for printed circuits.

[0012] According to an embodiment of the present invention, the shape of the pad is a rectangle with equal length and width, the length and width of the pad are less than the preset period, and the horizontal and vertical distances between adjacent pads are the difference between the preset period and the length or width of the pad.

[0013] According to an embodiment of the present invention, the band-stop filter further includes a resonant unit. The resonant unit replaces at least one of the multiple pads. The resonant unit is a circular pad, and the diameter of the resonant unit is less than the length of the pad.

[0014] According to an embodiment of the present invention, the resonant unit is adjacent to the metal microstrip line, and when there are multiple resonant units, the multiple resonant units are arranged on the same side of the metal microstrip line.

[0015] According to an embodiment of the present invention, the equivalent inductance between the resonant unit, the metal bottom plate and the metal column is determined according to the following formula:

[0016]

[0017] Wherein, L is the equivalent inductance, u0 is the magnetic permeability of vacuum, h1 is the distance between the resonant unit and the metal bottom plate, p is the period of the pad, d is the diameter of the metal column, and a is the radius of the metal column.

[0018] According to an embodiment of the present invention, the equivalent capacitance between the resonant unit and the metal top plate is determined according to the following formula:

[0019] C = kC0

[0020]

[0021] Wherein, C is the equivalent capacitance considering the edge effect, C0 is the ideal parallel plate capacitance, ε0 is the permittivity of vacuum, hair is the distance between the resonant unit and the metal top plate, S is the area of the resonant unit, r is the radius of the resonant unit, b is the aspect ratio, which is the ratio of the distance hair between the resonant unit and the metal top plate to the radius r of the resonant unit.

[0022] Compared with the prior art, the present invention has the following technical effects:

[0023] The currently widely used microstrip gap waveguide structure or metal structure has high loss or low integration. The present invention adopts a printed ridge gap waveguide structure. Since the printed ridge gap waveguide is completely shielded by metal, the radiation leakage of electromagnetic waves is reduced. There is no need for any electrical contact between the two parallel plates, so it has low transmission loss and also reduces the possibility of internal interference; the structure of the printed ridge gap waveguide is simpler and the processing difficulty is low, and it can be well integrated with other planar circuit structures (such as microstrip lines, substrate integrated waveguides, etc.), which is beneficial to the miniaturization and high-density integration of the system; in the present invention, while keeping the rest of the structure unchanged, the shape and size of the pads on the upper surface of the substrate are adjusted, and a resonant cavity is introduced to form a defect resonance, thereby realizing filtering. Each pad corresponds to a resonant point, thus increasing the filtering band. Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of a band-stop filter based on a printed ridge gap waveguide according to an embodiment of the present invention;

[0025] Figure 2 Schematic diagram of the basic unit according to an embodiment of the present invention;

[0026] Figure 3 Top view schematic diagram of the metal-free top plate of the band-stop filter according to an embodiment of the present invention;

[0027] Figure 4 is Figure 3 S-parameter diagram of the corresponding band-stop filter;

[0028] Figure 5 Top view schematic diagram of the metal-free top plate of the band-stop filter with one resonant unit according to an embodiment of the present invention;

[0029] Figure 6 is Figure 5 S-parameter diagram of the corresponding band-stop filter;

[0030] Figure 7 Top view schematic diagram of the metal-free top plate of the band-stop filter with two resonant units according to an embodiment of the present invention;

[0031] Figure 8 is Figure 7 S-parameter diagram of the corresponding band-stop filter.

[0032] Reference numerals:

[0033] Substrate 1; Metal bottom plate 2; Pad 3; Metal column 4; Metal microstrip line 5; Metal top plate 6; Resonant unit 7. Detailed description of the specific implementation

[0034] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where 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 by referring to the drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] The gap waveguide technology is a technology that uses an electromagnetic bandgap structure to achieve electromagnetic wave transmission. It forms a bandgap for electromagnetic waves in a specific frequency band by introducing a specific periodic structure (such as a metal column array) into the waveguide structure, thereby achieving effective control of the propagation of electromagnetic waves.

[0036] In a commonly used microstrip gap waveguide structure, during the transmission process, due to the influence of structural characteristics and dielectric materials, certain electromagnetic energy losses will occur. Such losses not only reduce the signal transmission efficiency but may also affect the overall performance of the system. Once the structure of the microstrip gap waveguide is determined and processed into a finished product, it is very difficult to fine-tune its electrical properties (such as resonant frequency, bandwidth, etc.), which limits its use in application scenarios that require high precision and flexible tuning. For an excellent metal gap waveguide structure, the processing accuracy requirements are relatively high. Especially in high-frequency applications, strict requirements are imposed on the surface finish, parallelism of the metal surface, and uniformity of the gap, etc. This increases the difficulty and complexity of processing. At the same time, due to the limitations of its volume and weight, as well as the compatibility issues with other circuit structures, the metal structure gap waveguide may face certain difficulties during system integration, which reduces the overall integration and design flexibility of the system.

[0037] To solve the above technical problems, the band-stop filter based on a printed ridge gap waveguide according to an embodiment of the present invention adopts a printed ridge gap waveguide structure and is completely shielded by metal, reducing the radiation leakage of electromagnetic waves. Therefore, it has lower transmission losses and enables high energy transmission efficiency. Compared with the traditional pin-type slot gap waveguide, the structure of the ridge gap waveguide is simpler, the processing difficulty is lower, and its assembly process is relatively convenient, which is beneficial to reducing production costs and improving production efficiency, and realizing miniaturization and high-density integration of the system.

[0038] The following describes the band-stop filter based on a printed ridge gap waveguide proposed by an embodiment of the present invention with reference to the accompanying drawings.

[0039] As Figure 1 shown, the band-stop filter based on a printed ridge gap waveguide according to an embodiment of the present invention includes: a substrate 1, a metal bottom plate 2, a plurality of pads 3, metal posts 4, a metal top plate 6, and a feeding part.

[0040] Among them, the substrate 1 is a bottom dielectric substrate, the metal bottom plate 2 is attached to the lower surface of the substrate 1, a plurality of pads 3 are attached to the upper surface of the substrate 1, and the metal posts 4 connect the plurality of pads 3 and the metal bottom plate 2. The metal top plate 6 is arranged parallel to the plurality of pads 3 at a preset distance. Among them, the preset distance is set according to the wavelength of electromagnetic waves. For example, the range of the preset distance can be 0.22 - 0.42 mm, and the medium between the plurality of pads 3 and the metal top plate 6 is air.

[0041] The feeding part adopts printed ridged gap waveguide feeding. The feeding part is a metal microstrip line 5. The metal microstrip line 5 divides multiple pads 3 into two equal parts on average. The multiple pads 3 are arranged in M columns on each side along the wide side direction of the substrate 1, N rows along the long side direction of the substrate 1, and are arranged on both sides of the metal microstrip line 5 at a preset period. The metal microstrip line 5 is connected to the metal bottom plate 2 through metal posts 4, where M and N are integers, and M≥2, N≥5. Among them, the preset period can be calibrated according to the actual situation, and M and N can be set according to the size of the band-stop filter. Exemplarily, in Figure 3 the shown band-stop filter, M is 3 and N is 11.

[0042] Specifically, the printed ridged gap waveguide technology is based on a parallel plate waveguide, where one is an ideal electric conductor and the other is designed as a periodically textured surface that behaves as an ideal magnetic conductor. Therefore, it can achieve no conductive contact between the two surfaces, that is, a cost-effective manufacturing process and a completely open structure. In addition, since the signal is transmitted in the air gap between the ideal electric conductor and the guiding structure introducing the ideal magnetic conductor, the dielectric loss can be ignored. That is to say, when the distance between the two plates is equal to or less than one-quarter wavelength, the space between the parallel plates behaves as a high-impedance region, which can suppress the propagation of parallel plate waves within the desired frequency range. The waveguide structure in the gap waveguide technology is realized by introducing ridges, slots or microstrip lines into the ideal magnetic conductor. In this way, the propagating wave is confined in the air gap between the PEC and the introduced guiding element.

[0043] Specifically, as Figure 2 shown, the mushroom-shaped structure unit composed of the metal bottom plate 2, pads 3, and metal posts 4 is embedded in the substrate. The mushroom-shaped structure unit can form an equivalent ideal magnetic conductor through periodic combination. The metal top plate 6 is an ideal electric conductor. The two conductors are placed in parallel and do not touch. At this time, an electromagnetic bandgap structure is formed. The electromagnetic wave is confined in the region between the electric conductor and the magnetic conductor and can only propagate along the metal ridge. That is, the electromagnetic wave propagates in the air gap between the metal top plate 6 and the metal microstrip line 5. This non-contact propagation method reduces the dielectric loss and improves the transmission efficiency, and can be applied to various fields such as microwave millimeter wave or 5G.

[0044] According to an embodiment of the present invention, the substrate 1 is rectangular, and the thickness of the substrate 1 is 0.8 - 1.2 mm. Preferably, the thickness of the substrate 1 can be 1 mm. Among them, the length and width of the substrate 1 can be set according to the size of the device. For example, the length L of the substrate 1 can be 16.5 mm, and the width W of the substrate 1 can be 10.5 mm.

[0045] According to an embodiment of the present invention, the material of the substrate 1 is a ceramic-filled reinforcing material, and the relative dielectric constant of the ceramic-filled reinforcing material is 3 and the relative permeability is 1.

[0046] According to an embodiment of the present invention, the length and width dimensions of the metal bottom plate 2 and the metal top plate 6 are the same as those of the substrate 1, the height of the metal column 4 is the same as the thickness of the substrate 1, and the length of the metal microstrip line 5 is the same as the length of the substrate 1.

[0047] For example, as Figure 3 shown in the band-stop filter, the thickness h1 of the substrate 1 is 1 mm, the length L of the substrate 1 is 16.5 mm, and the width W of the substrate 1 is 10.5 mm. Then, the length of the metal bottom plate 2 and the metal top plate 6 is 16.5 mm, the width is 10.5 mm, the height of the metal column 4 is 1 mm, the diameter of the metal column 4 is 0.25 mm, the length of the metal microstrip line 5 is 16.5 mm, and the width W1 of the metal microstrip line 5 is 1.18 mm.

[0048] According to an embodiment of the present invention, the materials of the metal bottom plate 2, the metal top plate 6, the pad 3, the metal column 4, and the metal microstrip line 5 are all copper, silver, or gold for printed circuits.

[0049] For cost considerations, the materials of the metal bottom plate 2, the metal top plate 6, the pad 3, the metal column 4, and the metal microstrip line 5 are preferably copper foils for printed circuits, and the thickness of the copper foil is usually 0.035 mm. That is to say, the thicknesses of the metal bottom plate 2, the metal top plate 6, the pad 3, and the metal microstrip line 5 are 0.035 mm.

[0050] According to an embodiment of the present invention, the shape of the pad 3 is a rectangle with equal length and width, the length and width of the pad 3 are less than a preset period, and the horizontal and vertical distances between adjacent pads 3 are the difference between the preset period and the length or width of the pad 3.

[0051] For example, as Figure 3 shown, the length W pad of the pad 3 is 1.26 mm, the width W pad of the pad 3 is 1.26 mm, the period P of the pad 3 is 1.5 mm, then the horizontal and vertical distances between adjacent pads 3 are 0.24 mm. There are periodically arranged pads 3 and metal columns 4 on the substrate 1, with 3 columns on each side along the width direction of the substrate 1, 11 rows along the length direction, and located on both sides of the metal microstrip line 5 with a period P of 1.5 mm. Figure 3 The S-parameter diagram corresponding to the band-stop filter based on the printed ridged waveguide shown in Figure 4 is as shown in

[0052] According to an embodiment of the present invention, as Figure 5 and Figure 7As shown, the band-stop filter further includes a resonant unit 7. The resonant unit 7 replaces at least one of the plurality of pads 3. The resonant unit 7 is a circular pad, and the diameter of the resonant unit 7 is smaller than the length of the pad 3.

[0053] For example, when the number of resonant units 7 is 1, as Figure 5 shown, a rectangular pad 3 is replaced by a resonant unit 7. The resonant unit 7 is a circular pad, and the diameter d1 of the resonant unit 7 is 0.65 mm, which is smaller than the length W pad of the pad 3 being 1.26 mm. At this time, the original periodic structure is destroyed, forming a resonant cavity. When electromagnetic waves pass through, the waves at the corresponding frequency points will be restricted at this defect resonance and cannot pass through, thus forming the filtering characteristic. Figure 5 The S-parameter diagram of the band-stop filter based on the printed ridged waveguide shown is as Figure 6 shown. When electromagnetic waves pass through this structure, a resonance point is formed at 26.5 GHz. When electromagnetic waves pass through, the waves at the 26.5 GHz point will be restricted at this defect resonance and cannot pass through, achieving a good filtering effect. It should be understood that the filtering frequency can be changed by adjusting the size of the resonant unit 7, and a corresponding filter can be designed.

[0054] When the number of resonant units 7 is 2, as Figure 7 shown, two rectangular pads 3 are replaced by resonant units 7, and the diameter d2 is 0.6 mm. Similarly, at this time, the original periodic structure changes, and the center resonance frequency is 27.27 GHz. When two co-frequency resonators are close to each other, mutual coupling will occur and split into two resonance points, thereby expanding the stopband width. Therefore, a resonant band can be formed to achieve the filtering of a certain range of electromagnetic wave frequencies. Figure 7 The S-parameter diagram of the band-stop filter based on the printed ridged waveguide shown is as Figure 8 shown. By introducing two defect resonances, good filtering is formed near 27.27 GHz. Since the split resonance points of the two resonant units 7 are used to broaden the stopband, a resonant band is formed, and good filtering characteristics are formed for the electromagnetic waves in the frequency range from 27.1 GHz to 27.3 GHz. It should be understood that the range of the stopband can be changed by adjusting the distance between the two pads 3, and at the same time, a high-order filter can also be formed by adjusting multiple pads 3 into resonant units 7.

[0055] It should be noted that the resonant unit 7 is a pad 3 with a reduced size. Using a circular structure will have better performance at high frequencies. For this through structure, using the resonant unit 7 at any position is equivalent. However, to avoid the port affecting the resonance frequency, the resonant unit 7 is generally placed in the middle.

[0056] It should be understood that the S-parameters, also known as Scatter parameters, are a type of parameter used to describe the characteristics of radio frequency circuit networks and are widely used in the microwave and radio frequency fields. S-parameters can provide information about signal reflection and transmission. In the context of a band-stop filter, Figure 4 、 Figure 6 and Figure 8 the meanings of the S-parameters are as follows:

[0057] S1,1 (input reflection coefficient): It represents the reflection coefficient of port 1 when port 2 is matched; a low S1,1 value means that the signal reflected at port 1 is small and the signal transmission efficiency is high.

[0058] S2,1 (forward transmission coefficient): It represents the forward transmission coefficient from port 1 to port 2 when port 2 is matched. This parameter describes the efficiency of signal transmission from port 1 to port 2. The larger the value of S2,1, the better. Ideally, it is 0 dB, indicating lossless transmission.

[0059] According to an embodiment of the present invention, the resonant unit 7 is adjacent to the metal microstrip line 5, and when there are multiple resonant units 7, the multiple resonant units 7 are arranged on the same side of the metal microstrip line 5.

[0060] Specifically, the closer the resonant unit 7 is to the metal microstrip line 5, the better the transmission effect of the electromagnetic wave. Therefore, the resonant unit 7 is arranged in a column adjacent to the metal microstrip line 5. And when there are multiple resonant units 7, they need to be placed on the same side of the microstrip line to facilitate adjusting the resonant band and expanding the stopband range. Placing them on both sides of the transmission line cannot form a resonant band.

[0061] Next, taking Figure 5 the relevant parameters of the corresponding band-stop filter as an example, the calculation process of the center frequency of the resonant unit 7 will be described in detail.

[0062] According to an embodiment of the present invention, the equivalent inductance between the resonant unit 7, the metal bottom plate 2, and the metal column 4 is determined according to the following formula:

[0063]

[0064] where L is the equivalent inductance, u0 is the vacuum permeability, h1 is the distance between the resonant unit 7 and the metal bottom plate 2, p is the period of the pad 3, d is the diameter of the metal column 4, and a is the radius of the metal column 4.

[0065] According to an embodiment of the present invention, the equivalent capacitance between the resonant unit 7 and the metal top plate 6 is determined according to the following formula:

[0066]

[0067] Among them, C is the equivalent capacitance considering the edge effect, C0 is the ideal parallel-plate capacitance, ε0 is the vacuum permittivity, hair is the distance between the resonant unit 7 and the metal top plate 6, S is the area of the resonant unit 7, d1 is the diameter of the resonant unit 7, r is the radius of the resonant unit 7, and b is the aspect ratio, which is the ratio of the distance hair between the resonant unit 7 and the metal top plate 6 to the radius r of the resonant unit 7.

[0068] Specifically, the calculation formula for the center frequency f of the resonant unit 7 is as follows:

[0069]

[0070] Among them, the charged ions between the resonant unit 7 and the metal bottom plate 2 will flow along the metal column 4 and the metal bottom plate 2, and this effect can be equivalent to an inductor L. The space between the resonant unit 7 and the metal top plate 6 can be equivalent to a parallel-plate capacitor. Figure 5 Substitute the relevant parameters of the corresponding band-stop filter: the distance h1 between the resonant unit 7 and the metal bottom plate 2 is 1 mm, the period p of the pad 3 is 1.5 mm, the diameter d of the metal column 4 is 0.25 mm, the distance hair between the resonant unit 7 and the metal top plate 6 is 0.32 mm, and the diameter d1 of the resonant unit 7 is 0.65 mm into the above formulas (1) and (2) respectively, the equivalent inductor L and equivalent capacitance C can be obtained, and then substitute the equivalent inductor L and equivalent capacitance C into the above formula (3) to obtain the center frequency f of the resonant unit 7.

[0071] In summary, through the analysis and design of the band-stop filter based on the printed ridge gap waveguide, and the simulation of the S-parameter curve, the present invention obtains that the filtering characteristics of different frequencies of electromagnetic waves can be changed by changing the pad size of the structure. The band-stop filter structure of the present invention can be equivalent to being composed of an ideal electric conductor and an ideal magnetic conductor. The magnetic conductor can be formed by a periodic electromagnetic structure, and then the electromagnetic wave is propagated through the air gap, which has the characteristics of low loss and low cost.

[0072] In summary, for the band-stop filter based on the printed ridge gap waveguide according to the embodiment of the present invention, the substrate, the metal bottom plate, the pads, and the metal columns form an equivalent ideal magnetic conductor through periodic combination, and the metal top plate is an ideal electric conductor. The two conductors are placed in parallel and do not contact. At this time, an electromagnetic bandgap structure is formed, and the electromagnetic wave is restricted in the region between the electric conductor and the magnetic conductor and can only propagate along the metal ridge, that is, the electromagnetic wave propagates in the air gap between the metal top plate and the metal microstrip line. Thus, the band-stop filter can enable the energy or electromagnetic wave to be transmitted in the air gap between the PEC and the PMC. This propagation method can reduce the dielectric loss and improve the transmission efficiency, which is more significant in the millimeter-wave band or even in the terahertz band, and has a simple structure and low processing difficulty, which is conducive to the miniaturization and high-density integration of the system.

[0073] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0074] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0075] In the present invention, unless otherwise clearly specified and limited, the terms such as "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0076] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A band-stop filter based on a printed ridge gap waveguide, characterized in that Comprising: A substrate; A metal bottom plate, which is attached to the lower surface of the substrate; Multiple pads, which are attached to the upper surface of the substrate; Metal posts, which connect the multiple pads to the metal bottom plate; A metal top plate, which is arranged parallel to the multiple pads at a preset distance directly above them; A feeding part, which uses printed ridged waveguide feeding. The feeding part is a metal microstrip line. The metal microstrip line divides the multiple pads into two equal parts on average. The multiple pads have M columns on each of the left and right sides along the width direction of the substrate, N rows along the length direction of the substrate, and are arranged on both sides of the metal microstrip line at a preset period. The metal microstrip line is connected to the metal bottom plate through the metal posts. Wherein, M and N are integers, and M≥2, N≥5; The shape of the pad is a rectangle with equal length and width. The length and width of the pad are less than the preset period. The horizontal and vertical distances between adjacent pads are the difference between the preset period and the length or width of the pad; The band-stop filter further includes a resonant unit, which replaces at least one of the multiple pads. The resonant unit is a circular pad, and the diameter of the resonant unit is less than the length of the pad; The resonant unit is adjacent to the metal microstrip line, and in the case where there are multiple resonant units, the multiple resonant units are arranged on the same side of the metal microstrip line.

2. The bandstop filter based on a printed ridge gap waveguide according to claim 1, characterized in that The substrate is rectangular, and the thickness of the substrate is 0.8 - 1.2 mm.

3. The band-stop filter based on a printed ridge gap waveguide according to claim 2, characterized in that, The material of the substrate is a ceramic-filled reinforcing material, and the relative dielectric constant of the ceramic-filled reinforcing material is 3 and the relative magnetic permeability is 1.

4. The band-stop filter based on a printed ridge gap waveguide according to claim 1, wherein, The length and width dimensions of the metal bottom plate and the metal top plate are the same as those of the substrate. The height of the metal post is the same as the thickness of the substrate. The length of the metal microstrip line is the same as the length of the substrate.

5. The band-stop filter based on a printed ridged waveguide according to claim 1, wherein The materials of the metal bottom plate, the metal top plate, the pad, the metal post, and the metal microstrip line are all copper, silver, or gold for printed circuits.

6. The band-stop filter based on a printed ridge gap waveguide according to claim 1, wherein, Determine the equivalent inductance between the resonant unit and the metal bottom plate and the metal post according to the following formula: Wherein, L is the equivalent inductance, u0 is the vacuum permeability, h1 is the distance between the resonant unit and the metal bottom plate, p is the period of the pad, d is the diameter of the metal post, and a is the radius of the metal post.

7. The band-stop filter based on a printed ridge gap waveguide according to claim 1, characterized in that, Determine the equivalent capacitance between the resonant unit and the metal top plate according to the following formula: C = kC0 Wherein, C is the equivalent capacitance considering the edge effect, C0 is the ideal parallel-plate capacitance, ε0 is the vacuum permittivity, hair is the distance between the resonant unit and the metal top plate, S is the area of the resonant unit, r is the radius of the resonant unit, and b is the aspect ratio, which is the ratio of the distance hair between the resonant unit and the metal top plate and the radius r of the resonant unit.

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