SIW dual-mode band-pass filter

Abstract

The invention discloses an SIW dual-mode band-pass filter which comprises at least three stacked SIW cavities, first coupling slots or second coupling slots are formed in the positions, attached to metal substrates, of the adjacent SIW cavities, the first coupling slots and the second coupling slots are located at the strongest magnetic field positions of a TE102 mode and a TE201 mode, and the first coupling slots and the second coupling slots are distributed in the stacking direction. And the types of the coupling slots between the adjacent SIW cavities are alternately distributed. According to the SIW dual-mode band-pass filter, the first coupling slot or the second coupling slot is formed in the attaching metal substrates of the adjacent SIW cavities, the first coupling slot and the second coupling slot are located at the strongest magnetic field positions of the TE102 mode and the TE201 mode, coupling of the TE102 mode and the TE201 mode can be independently controlled, and the SIW dual-mode band-pass filter with independent coupling control is achieved.

Description

Technical Field

[0001] The invention relates to a SIW dual-mode bandpass filter, belonging to the technical field of microwaves. Background Art

[0002] With the continuous development of communication systems, filters are also evolving towards miniaturization, low cost, low loss, high reliability, and ease of integration. Substrate-integrated waveguides combine microstrip and waveguide structures, offering the advantages of low loss, compact size, high Q, and easy integration. With the continuous advancement of wireless communication technology, a single filter is no longer sufficient for the application requirements of integrating multiple modes into a single system. In the design of dual-mode filters, independently controlling the coupling of the two modes remains a major challenge. Summary of the Invention

[0003] The present invention provides a SIW dual-mode bandpass filter, which solves the problems disclosed in the background technology.

[0004] According to one aspect of the present application, a SIW dual-mode bandpass filter is provided, comprising at least three stacked SIW cavities, wherein adjacent SIW cavities are provided with a first coupling slot or a second coupling slot on the adjacent metal substrates, and the first coupling slot and the second coupling slot are both located at TE 102 Mould and TE 201 At the point where the magnetic field of the mode is the strongest, the types of coupling slots between adjacent SIW cavities are distributed alternately along the stacking direction.

[0005] Furthermore, the first coupling slot is a cross slot, and the TE is controlled by adjusting the length and width of the first direction slot in the cross slot. 102 The magnetic coupling of the mode is controlled by adjusting the length and width of the second direction slot in the cross slot. 201 The magnetic coupling of the mode.

[0006] Furthermore, the cross slot is located at the center of the SIW cavity, the first direction slot is parallel to the first direction edge of the SIW cavity, and the second direction slot is parallel to the second direction edge of the SIW cavity.

[0007] Furthermore, the second coupling slot includes a first direction slot and a second direction slot, the first direction slot and the second direction slot are respectively close to the adjacent edges of the SIW cavity, and the TE is controlled by adjusting the length, width and distance of the first direction slot from the corresponding SIW cavity edge. 102 The magnetic coupling of the mode is controlled by adjusting the length and width of the second direction slot and the distance from the edge of the corresponding SIW cavity. 201 The magnetic coupling of the mode.

[0008] Furthermore, the midpoint of the first-direction slot is located on the second-direction centerline of the SIW cavity, and the first-direction slot is parallel to the first-direction edge of the SIW cavity; The midpoint of the second-direction slot is located on the first-direction center line of the SIW cavity, and the second-direction slot is parallel to the second-direction edge of the SIW cavity.

[0009] Furthermore, except for the SIW cavity where the feeding port is located, a pair of metal perturbation through holes are opened at the diagonals of the metal substrates of the other SIW cavities; the directions of the diagonals of the metal perturbation through holes of the same SIW cavity are consistent, and the directions of the diagonals of the metal perturbation through holes of adjacent SIW cavities are perpendicular.

[0010] Furthermore, the two feeding ports of the filter are both located on the metal substrate of the bottom SIW cavity, and both feeding ports adopt a transition structure from a microstrip line to a coplanar waveguide.

[0011] Furthermore, the feeding port is connected to the SIW cavity through a SIW transmission line.

[0012] The beneficial effects achieved by the present invention are as follows: the present invention provides the first coupling slot or the second coupling slot on the adjacent metal substrates of the SIW cavities, and the first coupling slot and the second coupling slot are both located at the TE 102 Mould and TE 201 The strongest magnetic field of the die can independently control TE 102 With TE 201 The SIW dual-mode bandpass filter with independent coupling control is realized by coupling the modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The exploded diagram of the SIW dual-mode bandpass filter; Figure 2 It is a top view of the SIW dual-mode bandpass filter; Figure 3 This is the S-parameter diagram of the SIW dual-mode bandpass filter. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. It is obvious that the embodiments described are only part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0015] Unless specifically stated otherwise, the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0016] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0017] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0018] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0019] It should be noted that like symbols and letters refer to like items in the following figures, so once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0020] At the same time, in the description of the embodiments of this application, the terms "first" and "second" are used only to distinguish the description and should not be understood as indicating or implying relative importance. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0021] An embodiment of the present application provides a SIW dual-mode bandpass filter, specifically a SIW dual-mode bandpass filter with independent coupling control, the filter includes at least three stacked SIW cavities, adjacent SIW cavities are provided with a first coupling slot or a second coupling slot on the adjacent metal substrate, the first coupling slot and the second coupling slot are both located at TE 102 Mould and TE 201 At the point where the magnetic field of the mode is the strongest, the types of coupling slots between adjacent SIW cavities are distributed alternately along the stacking direction.

[0022] It should be noted that the structures of all SIW cavities are similar, consisting of two metal substrates and an array of metallized through holes on a dielectric substrate between the two metal substrates. Generally, the radius of the metallized through holes on the dielectric substrate is consistent, such as a radius of 0.5 mm.

[0023] It should be noted that, in some embodiments, the first coupling slot may be a cross slot, and the TE can be controlled by adjusting the length and width of the first direction slot in the cross slot. 102 The magnetic coupling of the mode can be controlled by adjusting the length and width of the second direction slot in the cross slot. 201 The magnetic coupling of the modes.

[0024] The cross slot is located at the center of the SIW cavity, the intersection of the cross slot is located at the center of the cavity, the first direction slot is parallel to the first direction edge of the SIW cavity, and the second direction slot is parallel to the second direction edge of the SIW cavity.

[0025] The second coupling slot may include a first direction slot and a second direction slot, wherein the first direction slot and the second direction slot are respectively close to the adjacent edges of the SIW cavity. By adjusting the length, width and distance of the first direction slot from the corresponding SIW cavity edge, the TE can be controlled. 102 The magnetic coupling of the mode can be controlled by adjusting the length and width of the second direction slot and the distance from the edge of the corresponding SIW cavity. 201 The magnetic coupling of the mode.

[0026] The midpoint of the first direction slot is located on the second direction centerline of the SIW cavity, and the first direction slot is parallel to the first direction edge of the SIW cavity; the midpoint of the second direction slot is located on the first direction centerline of the SIW cavity, and the second direction slot is parallel to the second direction edge of the SIW cavity.

[0027] It should be noted that the coupling slots can be located at the edge or the center of the cavity. However, using the same coupling slot may introduce additional, unnecessary cross-coupling, resulting in interference. Therefore, staggering the two coupling slots can reduce this effect and improve the independent controllability of the filter coupling.

[0028] Take three stacked SIW cavities as an example, see Figure 1 The top metal substrate 1, the metallized through hole array on the first dielectric substrate 2 and the middle first metal substrate 3 constitute the top SIW cavity; the middle second metal substrate 4, the metallized through hole array on the second dielectric substrate 5 and the middle third metal substrate 6 constitute the middle SIW cavity; the middle fourth metal substrate 7, the feeding port and SIW microstrip line on the middle fourth metal substrate 7, the metallized through hole array on the third dielectric substrate 8 and the bottom metal substrate 9 constitute the bottom SIW cavity.

[0029] The metal substrates in the top and middle SIW cavities are the first and second metal substrates 3 and 4, respectively. Both have a first type of coupling slot, i.e., a cross slot. The metal substrates in the middle and bottom SIW cavities are the third and fourth metal substrates 6 and 7, respectively. Both have a second type of coupling slot, i.e., two slots located near the edge of the SIW cavity. The distance between the two slots in the second type of coupling slots and the corresponding SIW cavity edge can be 1.02 mm, and the width of all slots can be 0.4 mm.

[0030] definition Figure 1 The X direction is the first direction, and the Y direction is the second direction. The first X direction slot 11 and the first Y direction slot 12 in the cross slot provide TE 102 and TE 201 The magnetic coupling of the mode can be controlled by adjusting the length and width of the first X-direction slot 11 in the cross slot. 102 The magnetic coupling of the mode can be controlled by adjusting the length and width of the first Y-direction slot 12 in the cross slot. 201 Similarly, the second X-direction slot 15 and the second Y-direction slot 14 of the second coupling slot provide TE 102 and TE 201 The magnetic coupling of the mode can be controlled by adjusting the length and width of the second X-direction slot 15 and the distance from the corresponding SIW cavity edge. 102 The magnetic coupling of the mode can be controlled by adjusting the length and width of the second Y-direction slot 14 and the distance from the corresponding SIW cavity edge. 201 The first X-direction slot 11, the first Y-direction slot 12, the second X-direction slot 15 and the second Y-direction slot 14 realize the single coupling TE 102 and TE 201 mode, so that the filter can independently control the coupling of two modes in one resonant cavity.

[0031] It should be noted that in order to make the originally independent and orthogonal TE 102 Mode and TE 201 The mode field intensity is deflected to achieve the desired coupling effect. In some embodiments, except for the SIW cavity where the feeding port is located, a pair of metal perturbation through holes 10 are opened at the diagonals of the metal substrates of the other SIW cavities; the directions of the diagonals of the metal perturbation through holes 10 of the same SIW cavity are consistent, and the directions of the diagonals of the metal perturbation through holes 10 of adjacent SIW cavities are perpendicular.

[0032] See also Figure 1and Figure 2 , 10 pairs of metal perturbation through holes are opened in the top-layer SIW cavity and the middle-layer SIW cavity. Specifically, a pair of metal perturbation through holes 10 are opened on the top-layer metal substrate 1 and the middle first metal substrate 3, and the diagonal directions of the pairs of metal perturbation through holes 10 are consistent; a pair of metal perturbation through holes 10 are opened on the middle second metal substrate 4 and the middle third metal substrate 6, and the diagonal directions of the pairs of metal perturbation through holes 10 are consistent, but perpendicular to the diagonal directions of the pairs of metal perturbation through holes 10 in the top-layer SIW cavity.

[0033] In order to facilitate processing, in some embodiments, the two feeding ports (i.e., the input port and the output port) of the filter are set in the bottom SIW cavity. Specifically, the two feeding ports are both located on the metal substrate of the bottom SIW cavity. The two feeding ports both adopt a transition structure from a microstrip line to a coplanar waveguide, and the two feeding ports do not directly act on the SIW cavity. Instead, a section of SIW transmission line 13 is set, that is, the feeding ports are connected to the SIW cavity through the SIW transmission line 13. The cutoff frequency can be set by setting the length and width of the SIW transmission line 13, so as to suppress unnecessary low-order spurious TE 101 model.

[0034] Or Figure 1 For example, an input port 16 and an output port 17 are provided on the fourth metal substrate 7 in the middle of the bottom SIW cavity. Both the input port 16 and the output port 17 adopt a transition structure from a microstrip line to a coplanar waveguide, and are connected to the SIW cavity through a section of SIW transmission line 13.

[0035] See also Figure 3 , Figure 3 for Figure 1 The S parameter curve of the filter shows that the center frequency of the filter is 10 GHz, the 3-dB relative bandwidth is 6.9%, and the in-band return loss S11 is below -18 dB. It can be seen from the S parameter curve of the filter that the above filter can independently control the TE 102 and TE 201 The coupling coefficient of the two modes greatly expands the coupling coefficient control performance.

[0036] The filter has the first coupling slot or the second coupling slot on the adjacent metal substrates of the SIW cavities. The first coupling slot and the second coupling slot are both located at TE 102 Mould and TE 201 The strongest magnetic field of the die can independently control TE 102 With TE 201 The SIW dual-mode bandpass filter with independent coupling control is realized by coupling the modes.

[0037] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A SIW dual-mode bandpass filter, characterized in that: The invention comprises at least three stacked SIW cavities, wherein the adjacent metal substrates of the SIW cavities are provided with a first coupling slot or a second coupling slot, and the first coupling slot and the second coupling slot are both located at TE 102 Mould and TE 201 At the point where the magnetic field of the mode is the strongest, the types of coupling slots between adjacent SIW cavities are distributed alternately along the stacking direction.

2. The filter according to claim 1, wherein The first type of coupling slot is a cross slot. By adjusting the length and width of the first direction slot in the cross slot, the TE 102 The magnetic coupling of the mode is controlled by adjusting the length and width of the second direction slot in the cross slot. 201 The magnetic coupling of the mode.

3. The filter according to claim 2, characterized in that The cross slot is located at the center of the SIW cavity, the first direction slot is parallel to the first direction edge of the SIW cavity, and the second direction slot is parallel to the second direction edge of the SIW cavity.

4. The filter according to claim 1, wherein The second type of coupling slots includes a first direction slot and a second direction slot. The first direction slot and the second direction slot are respectively close to the adjacent edges of the SIW cavity. By adjusting the length, width and distance of the first direction slot from the corresponding SIW cavity edge, the TE 102 The magnetic coupling of the mode is controlled by adjusting the length and width of the second direction slot and the distance from the edge of the corresponding SIW cavity. 201 The magnetic coupling of the modes.

5. The filter according to claim 4, characterized in that The midpoint of the first-direction slot is located on the second-direction centerline of the SIW cavity, and the first-direction slot is parallel to the first-direction edge of the SIW cavity; The midpoint of the second-direction slot is located on the first-direction center line of the SIW cavity, and the second-direction slot is parallel to the second-direction edge of the SIW cavity.

6. The filter according to claim 1, wherein Except for the SIW cavity where the feeding port is located, a pair of metal perturbation through holes are opened at the diagonals of the metal substrates of the other SIW cavities; the diagonal directions of the metal perturbation through hole pairs in the same SIW cavity are consistent, and the diagonal directions of the metal perturbation through hole pairs in adjacent SIW cavities are perpendicular.

7. The filter according to claim 1, wherein The two feeding ports of the filter are both located on the metal substrate of the bottom SIW cavity, and both feeding ports adopt a transition structure from a microstrip line to a coplanar waveguide.

8. The filter according to claim 7, characterized in that The feeding port is connected to the SIW cavity through a SIW transmission line.

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