Four-band band-pass filter and communication chip

Abstract

The invention relates to the technical field of filters, in particular to a four-frequency-band band-pass filter and a communication chip, the four-frequency-band band-pass filter comprises a square SIW resonant cavity with four working modes, the similarity of electric field distribution of a mode 2 and a mode 1 is high, and the similarity of electric field distribution of a mode 4 and a mode 3 is high; two triangular SIW cavities, wherein each triangular SIW cavity has two working modes; the coupling window is positioned between the two triangular SIW cavities and the square SIW resonant cavity and is used for coupling an electromagnetic wave signal into the triangular SIW cavities from the square SIW resonant cavity; wherein the mode 1 and the mode 2 of the square SIW resonant cavity are respectively coupled with the first TE mode of the triangular SIW cavity to form two resonant units, and the mode 3 and the mode 4 of the square SIW resonant cavity are respectively coupled with the second TE mode of the triangular SIW cavity to form another two resonant units. According to the technical scheme, the four-band band-pass filter which is small in size and low in cost can be provided.

Description

Technical Field

[0001] The present disclosure relates to the technical field of filters, and in particular to a quad-band bandpass filter and a communication chip. Background Art

[0002] With the continuous development of modern communication technology, the demand for spectrum resources of many wireless communication devices is increasing, which poses a higher challenge to the effective utilization of spectrum resources. Multi-band communication devices are gradually being widely used, and filters as typical RF devices are no exception. However, traditional filters usually have defects and shortcomings such as a single operating frequency band, large size, and high production cost. Summary of the invention

[0003] In order to solve the problems in the related art, the embodiments of the present disclosure provide a quad-band bandpass filter and a communication chip.

[0004] In a first aspect, an embodiment of the present disclosure provides a four-band bandpass filter, comprising: A square SIW resonant cavity, wherein the square SIW resonant cavity has four working modes, namely mode 1, mode 2, mode 3 and mode 4, wherein, among the similarities of the electric field distributions of mode 1 with mode 2, mode 3 and mode 4, respectively, the similarity of the electric field distributions of mode 1 with mode 2 is the greatest, and among the similarities of the electric field distributions of mode 3 with mode 1, mode 2 and mode 4, respectively, the similarity of the electric field distributions of mode 3 with mode 4 is the greatest; Two triangular SIW cavities, wherein the triangular SIW cavities are dual-mode band-stop resonant cavities, and each triangular SIW cavity includes two working modes, namely a first TE mode and a second TE mode; A coupling window, located between the lower surface of the layer where the square SIW resonant cavity is located and the upper surface of the layer where the two triangular SIW cavities are located, for coupling the electromagnetic wave signal from the square SIW resonant cavity to the triangular SIW cavity; Among them, mode 1 and mode 2 of the square SIW resonant cavity are respectively coupled with the first TE mode of the triangular SIW cavity to form two resonance units, and mode 3 and mode 4 of the square SIW resonant cavity are respectively coupled with the second TE mode of the triangular SIW cavity to form another two resonance units.

[0005] In a possible implementation, it includes: A first dielectric substrate, wherein a plurality of metal through holes are provided on the first dielectric substrate to form the square SIW resonant cavity; a second dielectric substrate, wherein a plurality of metal through holes are disposed on the second dielectric substrate to form two triangular SIW cavities; A coupling layer is provided with a plurality of metal through holes to form the coupling window, and the coupling layer is located between the lower surface of the first dielectric substrate and the upper surface of the second dielectric substrate.

[0006] In a possible implementation, it further includes: A feeding layer, wherein the feeding layer adopts a diagonal feeding mode and the feeding layer is located above the upper surface of the first dielectric substrate; The ground layer is located below the lower surface of the second dielectric substrate.

[0007] In a possible implementation manner, the feed layer includes: A microstrip surface, wherein the microstrip surface has two notches, the two notches are respectively located above two target areas of the square SIW resonant cavity, and the electric field strength of the two target areas of the square SIW resonant cavity is greater than a predetermined value in four working modes; Two microstrip lines are respectively connected to two notches of the microstrip surface, and there are gaps between the two sides of the microstrip line and the microstrip surface.

[0008] In a possible implementation manner, the plurality of metal through holes on the first dielectric substrate avoids a region below the notch on the first dielectric substrate.

[0009] In a possible implementation, the coupling layer is square, and two metal through holes of the same size are provided on the coupling layer, and the two metal through holes are located on the target center line of the coupling layer and are spaced a predetermined distance from the center point of the coupling layer; wherein the target center line is parallel to a line connecting the center points of the two notches, and the target point on the coupling layer is in a straight line with the center point of the square SIW resonant cavity and the center points of the two triangular SIW cavities.

[0010] In a possible implementation manner, the metal through hole provided on the first dielectric substrate includes: The first metal through holes are arranged in a square shape and the second metal through holes have a perturbation function. The second metal through holes enable the square SIW resonant cavity formed by the first metal through holes to have four working modes.

[0011] In a possible implementation manner, the second metal through hole includes: a central metal through hole located at the center of the area surrounded by the first metal through holes; Four metal through holes whose centers are aligned with the center of the central metal through hole; Among them, two of the four metal through holes are located on one side of the central metal through hole, and the other two metal through holes are located on the other side of the central metal through hole, and the straight line is perpendicular to the line connecting the center points of the two notches.

[0012] In a possible implementation manner, the metal through hole on the second dielectric substrate includes: a third metal via arranged in a square pattern; The fourth metal through holes are arranged in a straight line, wherein the straight line formed by the fourth metal through holes is a diagonal line of a square area surrounded by the third metal through holes, and the diagonal line is perpendicular to a line connecting the center points of the two notches.

[0013] In a second aspect, an embodiment of the present disclosure provides a communication chip, the chip comprising a quad-band bandpass filter as described in any one of the first aspects.

[0014] According to the technical solution provided by the embodiment of the present disclosure, the four-band bandpass filter includes a square SIW resonant cavity with four working modes and two triangular SIW cavities, the triangular SIW cavity is a dual-mode band-stop resonant cavity, and each triangular SIW cavity has two working modes. A coupling window is set between the lower surface of the layer where the square SIW resonant cavity is located and the upper surface of the layer where the two triangular SIW cavities are located, so that the electromagnetic wave signal is coupled from the square SIW resonant cavity to the triangular SIW cavity; wherein, mode 1 and mode 2 of the square SIW resonant cavity are respectively coupled with the first TE mode of the triangular SIW cavity to form two resonant units, and mode 3 and mode 4 of the square SIW resonant cavity are respectively coupled with the second TE mode of the triangular SIW cavity to form another two resonant units, so that four resonant units are formed to achieve four-band working characteristics. The square SIW resonant cavity, the triangular SIW cavity and the coupling window in the four-band bandpass filter have simple structures and low processing costs. The four-band bandpass filter can be coupled by a layer of square SIW resonant cavity and a layer of triangular SIW cavity, thereby realizing the miniaturization of the four-band bandpass filter.

[0015] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features, objectives and advantages of the present disclosure will become more apparent through the following detailed description of non-limiting embodiments in conjunction with the accompanying drawings. In the accompanying drawings:

[0017] Figure 1 A schematic diagram of a four-band bandpass filter provided by an embodiment of the present disclosure is shown.

[0018] Figure 2A The electric field distribution diagrams of four working modes of the square SIW resonant cavity provided by the embodiments of the present disclosure are shown.

[0019] Figure 2BA schematic diagram of an S-parameter simulation curve of a diagonally fed bandpass filter formed by the square SIW resonant cavity provided by an embodiment of the present disclosure is shown.

[0020] Figure 3A A schematic diagram of a quad-band bandpass filter provided by an embodiment of the present disclosure is shown.

[0021] Figure 3B A schematic diagram of the layered structure of a four-band bandpass filter provided by an embodiment of the present disclosure is shown.

[0022] Figure 4A A schematic diagram showing a partial structure of a quad-band bandpass filter provided by an embodiment of the present disclosure is shown.

[0023] Figure 4B A schematic diagram of a feeding layer of a quad-band bandpass filter provided by this embodiment is shown.

[0024] Figure 5 A schematic diagram of an S-parameter simulation curve of a four-band bandpass filter provided by an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0025] Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement them. In addition, for the sake of clarity, parts not related to the description of the exemplary embodiments are omitted in the accompanying drawings.

[0026] In the present disclosure, it should be understood that terms such as "include" or "have" are intended to indicate the presence of features, numbers, steps, behaviors, components, parts, or a combination thereof disclosed in the present specification, and are not intended to exclude the possibility that one or more other features, numbers, steps, behaviors, components, parts, or a combination thereof exist or are added.

[0027] It should also be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0028] Figure 1 FIG. 1 is a schematic diagram of a four-band bandpass filter provided by an embodiment of the present disclosure. Figure 1 As shown, the quad-band bandpass filter includes a square SIW (Substrate integrated waveguide) resonant cavity 11, two triangular SIW cavities 12 and a coupling window 13.

[0029] like Figure 1 As shown, the coupling window 13 is located between the lower surface of the layer where the square SIW resonant cavity 11 is located and the upper surface of the layer where the two triangular SIW cavities 12 are located.

[0030] The square SIW resonant cavity 11 has four operating modes, for example, Figure 2A 1 shows the electric field distribution diagram of four working modes of the square SIW resonant cavity provided by the embodiment of the present disclosure. The electric field distribution here refers to the distribution of the electric field intensity, such as Figure 2A As shown, the four working modes of the square SIW resonant cavity 11 can be recorded as mode 1, mode 2, mode 3 and mode 4. Figure 2A It can be clearly seen that the similarity between the electric field distribution of mode 2 and mode 1 is significantly greater than the similarity between the electric field distribution of mode 3 and mode 1, as well as the similarity between the electric field distribution of mode 4 and mode 1, that is, the similarity between the electric field distribution of mode 2 and mode 1 is the greatest, and the similarity between the electric field distribution of mode 4 and mode 3 is significantly greater than the similarity between the electric field distribution of mode 1 and mode 3, as well as the similarity between the electric field distribution of mode 2 and mode 3, that is, the similarity between the electric field distribution of mode 4 and mode 3 is the greatest. Here, the similarity of the electric field distribution can be determined by calculating the similarity of the electric field distribution diagrams.

[0031] The triangular SIW cavity 12 is a dual-mode band-stop resonant cavity, and each triangular SIW cavity 12 includes two working modes, both of which are TE (transverse electric) modes. The TE mode refers to a propagation mode in which the longitudinal component of the electric field in the propagation direction of the electromagnetic wave is zero, and the longitudinal component of the magnetic field is not zero, which can be recorded as the first TE mode and the second TE mode. By way of example, the two TE modes used by the triangular SIW cavity 12 can be the TE120 mode and the TE230 mode. The TE120 mode and the TE230 mode are working modes that are clear to people in this field and will not be repeated here.

[0032] The coupling window 13 can couple the electromagnetic wave signal from the square SIW resonant cavity 11 to the triangular SIW cavity. Mode 1 and mode 2 of the square SIW resonant cavity 11 can be coupled with the first TE mode of the triangular SIW cavity 12 to form two resonance units, and mode 3 and mode 4 of the square SIW resonant cavity 11 can be coupled with the second TE mode of the triangular SIW cavity 12 to form another two resonance units. In this way, a total of four resonance units are formed to realize a bandpass filter of four frequency bands.

[0033] It should be noted that the square SIW resonant cavity 11 and the two triangular SIW cavities 12 can be formed in a variety of ways, as long as they can form the square SIW resonant cavity 11 and the triangular SIW cavity 12 structures that can realize the above-mentioned four-band bandpass filter, and there is no limitation here.

[0034] The quad-band bandpass filter provided in this embodiment includes a square SIW resonant cavity 11 with four working modes and two triangular SIW cavities 12. The triangular SIW cavity 12 is a dual-mode band-stop resonant cavity. Each triangular SIW cavity 12 includes two working modes. A coupling window 13 is provided between the lower surface of the layer where the square SIW resonant cavity 11 is located and the upper surface of the layer where the two triangular SIW cavities 12 are located, so that the electromagnetic wave signal is coupled from the square SIW resonant cavity 11 to the triangular SIW cavity; wherein the mode 1 and the mode 2 of the square SIW resonant cavity 11 are respectively coupled to the triangular SIW The first TE mode of the cavity 12 is coupled to form two resonance units, and the modes 3 and 4 of the square SIW resonance cavity 11 are respectively coupled with the second TE mode of the triangular SIW cavity 12 to form another two resonance units, so that four resonance units are formed to achieve a four-band working characteristic. The square SIW resonance cavity 11, the triangular SIW cavity 12 and the coupling window 13 in the four-band bandpass filter have simple structures and low processing costs. A four-band bandpass filter can be coupled by a layer of square SIW resonance cavity 11 and a layer of triangular SIW cavity 12, thereby realizing the miniaturization of the four-band bandpass filter.

[0035] In one possible implementation, Figure 3A A schematic diagram of a quad-band bandpass filter provided by an embodiment of the present disclosure is shown. Figure 3B FIG. 2 shows a schematic diagram of a hierarchical structure of a four-band bandpass filter provided by an embodiment of the present disclosure. Figure 3B As shown, the four-band bandpass filter includes:

[0036] A first dielectric substrate 21, wherein a plurality of metal through holes are provided on the first dielectric substrate 21 to form a square SIW resonant cavity; A second dielectric substrate 22, wherein a plurality of metal through holes are provided on the second dielectric substrate 22 to form two triangular SIW cavities; The coupling layer 23 is provided with a plurality of metal through holes to form the coupling window. The coupling layer 23 is located between the lower surface of the first dielectric substrate 21 and the upper surface of the second dielectric substrate 22 .

[0037] Here, if Figure 3B As shown, the quad-band bandpass filter comprises a first dielectric substrate 21 , a coupling layer 23 and a second dielectric substrate 22 , wherein the coupling layer 23 is located between the lower surface of the first dielectric substrate 21 and the upper surface of the second dielectric substrate 22 .

[0038] Figure 4A FIG. 1 is a schematic diagram showing a partial structure of a four-band bandpass filter provided by an embodiment of the present disclosure, such as Figure 4AAs shown, the first dielectric substrate 21 is provided with a plurality of metal through holes, which can be arranged in a rectangular shape to form a square SIW resonant cavity; the second dielectric substrate 22 is provided with a plurality of metal through holes, which can be arranged in two symmetrical isosceles right triangles to form two triangular SIW cavities; and the coupling layer 23 is provided with two metal through holes to form the coupling window.

[0039] It should be noted here that there is no limitation on the number, size, arrangement, etc. of the above-mentioned metal through holes, as long as the above-mentioned four-band bandpass filter can be realized.

[0040] This embodiment uses a double-layer dielectric substrate to realize a four-band bandpass filter, and the overall structure is miniaturized through a double-layer PCB process.

[0041] In a possible implementation, Figure 3B As shown, the four-band bandpass filter also includes: A feeding layer 24, wherein the feeding layer 24 adopts a diagonal feeding mode and is located above the upper surface of the first dielectric substrate 21; The ground layer 25 is located below the lower surface of the second dielectric substrate 22 and is used for grounding to form a loop. The ground layer 25 may be a metal substrate.

[0042] In this way, the electromagnetic wave signal is coupled from the square SIW resonant cavity on the feeding layer 24 and the first dielectric substrate 21 to the triangular SIW cavity on the second dielectric substrate 22 below, and finally reaches the ground layer 25 to form a loop.

[0043] This implementation adopts a diagonal feeding method to realize a bandpass filter with a wide frequency ratio.

[0044] In one possible implementation, Figure 4B FIG. 4 shows a schematic diagram of a feeding layer of a quad-band bandpass filter provided in this embodiment. Figure 4B As shown, the feeding layer 24 includes a microstrip surface 241 and two microstrip lines 242 .

[0045] The feeding layer 24 may be a metal plate. The feeding layer 24 adopts diagonal feeding. Two microstrip lines 242 may be arranged at two notches 2411 at a diagonal of the microstrip surface 241. In this embodiment, for better feeding, the two notches 2411 are respectively located above two target areas of the square SIW resonant cavity on the microstrip surface 241. The electric field strength at the two target areas of the square SIW resonant cavity is greater than a predetermined value in the four working modes. Figure 2AThe red area in the electric field distribution diagram of the four working modes is the area with the strongest electric field distribution in the four working modes of the square SIW resonant cavity. The area where the electric field strength in the four working modes of the square SIW resonant cavity is greater than the predetermined value can be Figure 2A The red areas in the four working modes shown are overlapped in the horizontal diagonal area of ​​the square SIW resonant cavity, which is also the area with the strongest electric field distribution. The area close to the right angle on the vertical diagonal line is the area with the smallest electric field strength, so the filter is fed in a horizontal diagonal form. Figure 3B It can be seen that the notch 2411 is located at the strongest point of the electric field distribution corresponding to the four working modes of the square SIW resonant cavity on the substrate. Figure 4B As shown, two microstrip lines 242 are respectively connected to the two basic gaps 2411 , and there are gaps between the two sides of the microstrip line 242 and the microstrip surface 241 .

[0046] Here, since the notch 2411 is located at the strongest point of the electric field distribution in the four working modes, and because the resonance modes of mode 1 and mode 2 are relatively close, and the resonance modes of mode 3 and mode 4 are relatively close, there should be two passbands and four transmission poles in the final frequency response. By performing electromagnetic modeling and simulation analysis on the bandpass filter formed by the diagonally fed square SIW resonant cavity, the following is obtained: Figure 2B The S parameter simulation curve shown is Figure 2B In the curve graph shown, the horizontal axis is frequency, the vertical axis is S parameter, the solid line is S11 curve, and the dotted line is S21 curve; Figure 2B It can be seen that the resonant frequencies of the four working modes are 14.3 GHz, 14.9 GHz, 22.5 GHz, and 23.7 GHz, respectively. The simulation results verify the above analysis.

[0047] It should be noted here that the size of the microstrip surface 241, the size of the microstrip line 242 and the size of the gap are not limited here, as long as they can achieve good feeding for the above-mentioned four-band bandpass filter.

[0048] In a possible implementation, Figure 4A As shown, the metal through hole on the first dielectric substrate 21 avoids the area below the notch 2411 on the first dielectric substrate 21, and Figure 3B It can be seen that there is no metal through hole in the area below the notch 2411 on the microstrip surface 241, and the square-arranged metal through holes forming the square SIW resonant cavity have "break points" at the diagonals, so that the metal through holes can be prevented from affecting the feeding of the feeding layer 24, thereby achieving a better feeding effect.

[0049] In a possible implementation, the coupling layer 23 is square, and two metal through holes 231 of the same size are provided on the coupling layer 23. The two metal through holes 231 are located on the target center line of the coupling layer 23, and are spaced a predetermined distance from the target point on the coupling layer 23. The target center line is a center line on the coupling layer 23 parallel to a line connecting the center points of the two notches 2411. The target point on the coupling layer 23 and the center point of the square SIW resonant cavity and a center point corresponding to the combination of two triangular SIW cavities are on a straight line, and the straight line may be perpendicular to the coupling layer 23.

[0050] It should be noted here that the size of the metal through hole 231 on the coupling layer 23 and the predetermined distance are not limited, as long as the coupling function in the above-mentioned four-band bandpass filter can be achieved.

[0051] In a possible implementation, Figure 4A As shown, the metal through holes arranged on the first dielectric substrate 21 include: first metal through holes 211 arranged in a square and second metal through holes 212 with a disturbance function. The second metal through holes 212 enable the square SIW resonant cavity formed by the first metal through holes 211 to work in four working modes.

[0052] In a possible implementation, Figure 4A As shown, the second metal through hole 212 includes a central metal through hole 2121 located at the center of the area surrounded by the first metal through hole 211 and four metal through holes 2122 whose centers are in a straight line with the center of the central metal through hole 2121, two of the four metal through holes 2122 are located on one side of the central metal through hole 2121, and the other two metal through holes are located on the other side of the central metal through hole 2121. Figure 3A and 3B It can be seen that the straight line is perpendicular to the line connecting the center points of the two notches 2411 .

[0053] Here, if Figure 4A As shown, the first metal through hole 211 provided on the first dielectric substrate can form a square resonant cavity. Under the disturbance of the second metal through hole 212, Figure 4B The feed layer pair Figure 4A After the square resonant cavity shown is fed diagonally, it can be determined by actual measurement that the square resonant cavity has Figure 2A Four working modes are shown.

[0054] In a possible implementation, Figure 4A As shown, the metal through hole on the second dielectric substrate 22 includes: The third metal through holes 221 are arranged in a square and the fourth metal through holes 222 are arranged in a straight line. The straight line formed by the fourth metal through holes 222 is the diagonal of the square area surrounded by the third metal through holes 221 , and the diagonal is perpendicular to the line connecting the center points of the two notches 2411 .

[0055] For example, the four-band bandpass filter provided by the present disclosure may include Figure 3B The hierarchical structure shown in the figure, the quad-band bandpass filter comprises a feed layer 24, a first dielectric substrate 21, a coupling layer 23, a second dielectric substrate 22 and a ground layer 25 from top to bottom, wherein the first dielectric substrate 21 and the second dielectric substrate 22 can be squares of the same shape, and the microstrip surface 241 in the feed layer 24, the coupling layer 23 and the ground layer 25 are also squares; the feed layer 24 comprises: a microstrip surface 241, two notches 2411 and two microstrip lines 242, the first dielectric substrate 21 is provided with first metal through holes 211 arranged in a square and second metal through holes 212 with a perturbation function, the diagonal line of the square formed by the first metal through holes 211 overlaps with the center line of the square first dielectric substrate 21, and the center connecting line of a central metal through hole 2121 in the second metal through hole 212 and four metal through holes 2122 overlaps with the center line of the square first dielectric substrate 21, and the center connecting line of the circle of the first metal through hole 2121 and the first metal through hole 2122 overlaps with the first metal through hole 2121 in the second metal through hole 2121 and the first metal through hole 2122 The center point line of the two notches 2411 is perpendicular, and two metal through holes of the same size are arranged on the coupling layer 23. The two metal through holes are located on the target center line of the coupling layer 23 and are spaced a predetermined distance from the center point of the coupling layer 23. The target center line is parallel to the center point line of the two notches 2411. The metal through holes on the second dielectric substrate 22 include third metal through holes 221 arranged in a square and fourth metal through holes 222 arranged in a straight line. The straight line formed by the fourth metal through holes 222 is the diagonal of the square area surrounded by the third metal through holes 221, so as to form two isosceles triangles. The diagonal line is perpendicular to the center point line of the two notches 2411. The square area formed by the third metal through holes 221 completely overlaps with the square area formed by the first metal through holes 211.

[0056] The materials of the first dielectric substrate 21 and the second dielectric substrate 22 are both Rogers 5880 plates, with a dielectric constant of 2.2, a loss tangent angle tanδ of 0.0009, and a thickness of 0.508 mm. By performing electromagnetic modeling on the above-mentioned four-band bandpass filter structure, after simulation and optimization, the structural parameters of the four-band bandpass filter are finally obtained as shown in Table 1 below. The S parameter simulation results of the four-band bandpass filter are shown in Figure 5 As shown, Figure 5 The horizontal axis is frequency, the vertical axis is S parameter, the solid line is S11 curve, and the dotted line is S21 curve.

[0057]

[0058] like Figure 4A As shown, W0 in Table 1 is the width of the microstrip line 242, L0 is the length of the microstrip line 242, W1 is the side length of the square microstrip surface 241, W2 is the width of the gap between the two sides of the microstrip line 242 and the substrate, L3 is the length of the gap between the two sides of the microstrip line 242 and the substrate, the side length of the square formed by the first metal through holes 211 is W3, the diameter of the first metal through hole 211 is P, the diameter of the central metal through hole 2121 in the second metal through hole 212 is Rc, the diameter of the four metal through holes is rc, the center spacing between two adjacent metal through holes in the four metal through holes is L1, the center spacing between the central metal through hole 2121 and the adjacent metal through holes in the four metal through holes is L2, W4 is the side length of the square formation 25, and the diameter of the third metal through hole 221 is P.

[0059] from Figure 5 It can be seen that the four passband center frequencies of the four-band bandpass filter are 14.88GHz, 15.84GHz, 22.40GHz, and 23.76GHz, and the 3dB relative bandwidths are 2.3%, 1.9%, 4.4%, and 2.9%, respectively. The insertion losses are 1.36dB, 1.62dB, 0.76dB, and 1.09dB, respectively. The return losses of the first two passbands are better than 15dB, and the return losses of the last two passbands are better than 22dB.

[0060] Of course, if the relevant parameters of the first dielectric substrate 21, the second dielectric substrate 22, the coupling layer 23, the feeding layer 24 and the ground layer 25 change, such as the material type changes, the thickness changes such as the dielectric substrate thickness changes, etc. Figure 3B Based on the structure of the four-band bandpass filter shown, the parameters in the above Table 1 can be adjusted accordingly through simulation and optimization, so as to realize the four-band bandpass filter of the required frequency band, which will not be described in detail here.

[0061] The present disclosure also provides a communication chip, which includes the above-mentioned four-band bandpass filter. The four-band bandpass filter has a compact size and a simple structure, is easy to process, can be integrated with other circuits to form a corresponding communication chip, and has broad application prospects in the fields of modern communications, etc. For example, the four-band bandpass filter can be integrated with a radio frequency circuit to form a communication chip.

[0062] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present disclosure is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present disclosure (but not limited to) by each other.

Claims

1. A four-band bandpass filter, characterized in that: include: A square substrate integrated waveguide SIW resonant cavity, wherein the square SIW resonant cavity has four working modes, namely mode 1, mode 2, mode 3 and mode 4, wherein, among the similarities of the electric field distributions of mode 1 with mode 2, mode 3 and mode 4, respectively, the similarity of the electric field distributions of mode 1 with mode 2 is the greatest, and among the similarities of the electric field distributions of mode 3 with mode 1, mode 2 and mode 4, respectively, the similarity of the electric field distributions of mode 3 with mode 4 is the greatest; Two triangular SIW cavities, wherein the triangular SIW cavities are dual-mode band-stop resonant cavities, and each triangular SIW cavity includes two working modes, namely a first transverse electric wave TE mode and a second TE mode; A coupling window, located between the lower surface of the layer where the square SIW resonant cavity is located and the upper surface of the layer where the two triangular SIW cavities are located, for coupling the electromagnetic wave signal from the square SIW resonant cavity to the triangular SIW cavity; Among them, mode 1 and mode 2 of the square SIW resonant cavity are respectively coupled with the first TE mode of the triangular SIW cavity to form two resonance units, and mode 3 and mode 4 of the square SIW resonant cavity are respectively coupled with the second TE mode of the triangular SIW cavity to form another two resonance units.

2. The quad-band bandpass filter according to claim 1, characterized in that: Also includes: A first dielectric substrate, wherein a plurality of metal through holes are provided on the first dielectric substrate to form the square SIW resonant cavity; a second dielectric substrate, wherein a plurality of metal through holes are disposed on the second dielectric substrate to form two triangular SIW cavities; A coupling layer is provided with a plurality of metal through holes to form the coupling window, and the coupling layer is located between the lower surface of the first dielectric substrate and the upper surface of the second dielectric substrate.

3. The quad-band bandpass filter according to claim 2, characterized in that: Also includes: A feeding layer, wherein the feeding layer adopts a diagonal feeding mode and the feeding layer is located above the upper surface of the first dielectric substrate; The ground layer is located below the lower surface of the second dielectric substrate.

4. The quad-band bandpass filter according to claim 3, characterized in that: The feed layer comprises: A microstrip surface, wherein the microstrip surface has two notches, the two notches are respectively located above two target areas of the square SIW resonant cavity, and the electric field strength of the two target areas of the square SIW resonant cavity is greater than a predetermined value in four working modes; Two microstrip lines are respectively connected to two notches of the microstrip surface, and there are gaps between the two sides of the microstrip line and the microstrip surface.

5. The quad-band bandpass filter according to claim 4, characterized in that: The plurality of metal through holes on the first dielectric substrate avoids a region below the notch on the first dielectric substrate.

6. The quad-band bandpass filter according to claim 4, characterized in that: The coupling layer is square, and two metal through holes of the same size are provided on the coupling layer. The two metal through holes are located on the target center line of the coupling layer and are spaced a predetermined distance from the center point of the coupling layer; wherein the target center line is parallel to a line connecting the center points of the two notches, and the target point on the coupling layer is in a straight line with the center point of the square SIW resonant cavity and the center points of the two triangular SIW cavities.

7. The quad-band bandpass filter according to claim 4, characterized in that: The plurality of metal through holes provided on the first dielectric substrate include: The first metal through holes are arranged in a square shape and the second metal through holes have a perturbation function. The second metal through holes enable the square SIW resonant cavity formed by the first metal through holes to have four working modes.

8. The quad-band bandpass filter according to claim 7, characterized in that: The second metal through hole comprises: a central metal via located at the center of the area surrounded by the first metal vias; Four metal through holes whose centers are aligned with the center of the central metal through hole; Among them, two of the four metal through holes are located on one side of the central metal through hole, and the other two metal through holes are located on the other side of the central metal through hole, and the straight line is perpendicular to the line connecting the center points of the two notches.

9. The quad-band bandpass filter according to claim 8, characterized in that: The plurality of metal through holes on the second dielectric substrate include: a third metal via arranged in a square pattern; The fourth metal through holes are arranged in a straight line, wherein the straight line formed by the fourth metal through holes is a diagonal line of a square area surrounded by the third metal through holes, and the diagonal line is perpendicular to a line connecting the center points of the two notches.

10. A communication chip, characterized in that: A four-band bandpass filter comprising any one of claims 1-9.

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