A dielectric resonator negative coupling structure and a dielectric waveguide filter using the same

Abstract

The present invention provides a dielectric resonator negative coupling structure and a dielectric waveguide filter using the same, which can effectively solve the problem of negative coupling, avoid the influence of resonance peaks, weaken parasitic coupling, and have more symmetrical frequency response characteristics; the dielectric resonator comprises at least two connected dielectric resonators, a coupling structure is provided at the connection between the dielectric resonators, the coupling structure comprises an elongated blind groove, the blind groove is opened at the connection between the dielectric resonators, the length of the blind groove is 40% to 100% of the length of the connection between the dielectric resonators, and the depth of the blind groove is 50% to 95% of the height of the connection between the dielectric resonators.

Description

Technical Field

[0001] The present invention relates to the technical field of communication equipment components, in particular to a dielectric resonator negative coupling structure and a dielectric waveguide filter using the same. Background Art

[0002] With the development of mobile communication technology, miniaturization and integration have become the development trend of communication equipment. Among them, dielectric waveguide filters are based on dielectric resonators and achieve filtering performance through coupling between resonators. Compared with traditional metal cavity filters, they have the advantages of small size, low insertion loss, low cost, and easy integration. In order to achieve increasingly stringent performance requirements, such as having a steep transition band and low insertion loss, negative coupling between resonators is usually required. At present, the negative coupling between dielectric waveguide resonators is mainly achieved by setting blind holes between resonators. For example, an existing dielectric waveguide filter, such as Figure 1 As shown in FIG. 1 , the dielectric resonator includes at least one negative coupling blind hole 3, which is located on the body surface of the dielectric resonator 1 and the dielectric resonator 2 at the connection position, and the two structures require that the depth of the negative coupling blind hole 3 is at least twice the depth of the tuning hole 4 on the dielectric resonator, so the bottom of the negative coupling blind hole is very close to the bottom surface of the resonator, thereby forming a strong capacitance effect to achieve negative coupling; however, due to the deep depth of the negative coupling blind hole, the hole body forms an inductance effect, and the hole bottom forms a capacitance effect, thereby forming a resonance effect similar to a series resonance circuit, which will form a resonance peak on the filter filtering curve and cause the filter's suppression performance to fail to meet the requirements of a specific frequency band. Generally, the position of the resonance peak in the frequency domain is determined by the negative coupling blind hole. The depth of the negative coupling blind hole is determined by the depth of the hole. The deeper the depth, the lower the frequency, and vice versa. The depth of the negative coupling blind hole is determined by the coupling amount designed according to the customer's indicators. That is to say, once the customer's indicators are determined, the depth of the negative coupling blind hole is also determined, and the position of the resonance peak caused by the negative coupling blind hole in the frequency domain cannot be adjusted, which will cause the negative coupling structure to fail to meet the filter performance requirements when the resonance peak falls in the frequency band with higher suppression requirements; in addition, since the axial cross-section of the negative coupling blind hole is small and the connection area between the resonators is large, other dielectric resonators can easily generate parasitic coupling through this connection area, resulting in the frequency response characteristics of the structurally symmetrical dielectric filter being high on one side and low on the other side, and the required symmetrical characteristics cannot be obtained. Summary of the invention

[0003] In view of the above problems, the present invention provides a dielectric resonator negative coupling structure and a dielectric waveguide filter using the same, which can effectively solve the problem of negative coupling, avoid the influence of resonance peaks, weaken parasitic coupling, and have a more symmetrical frequency response characteristic.

[0004] Its technical solution is as follows: A dielectric resonator negative coupling structure includes at least two connected dielectric resonators, and a coupling structure is provided at the connection between the dielectric resonators. It is characterized in that: the coupling structure includes an elongated blind slot, the blind slot is opened at the connection between the dielectric resonators, the length of the blind slot is 40% - 100% of the length of the connection between the dielectric resonators, and the depth of the blind slot is 50% - 95% of the height of the connection between the dielectric resonators.

[0005] It is further characterized in that:

[0006] The material of the dielectric resonator is ceramic dielectric material or polymer material; the shape of the dielectric resonator is circular or polygonal block;

[0007] A resonant blind hole is provided at the center of the surface of each dielectric resonator, and the depth of the resonant blind hole is less than the depth of the blind slot;

[0008] The blind slot extends from one side of the connection between the dielectric resonators and does not penetrate the dielectric resonator. There is a distance between the wall surface of the blind slot and the other side of the connection. The unseparated part on the connection between the dielectric resonators forms a coupling part, and the coupling part is L-shaped;

[0009] The blind slot is opened at the middle position of the connection between the dielectric resonators, and there are distances between the two side walls of the blind slot and both sides of the connection to form a closed slot structure. The unseparated part on the connection between the dielectric resonators forms a coupling part, and the coupling part is 冂-shaped;

[0010] The height of the horizontal part of the coupling part is not greater than half of the height of the connection between the dielectric resonators.

[0011] A dielectric waveguide filter includes the above-mentioned dielectric resonator negative coupling structure.

[0012] The beneficial effect of the present invention is that by opening a blind slot at the connection between the dielectric resonators, the length of the blind slot is 40% - 100% of the length of the connection between the dielectric resonators, and the depth of the blind slot is 50% - 95% of the height of the connection between the dielectric resonators. By correspondingly adjusting the length and depth of the blind slot, it is possible to ensure both the negative coupling amount and the filter performance meet the suppression requirements, avoid the influence of resonant peaks, and since the cross-sectional area of the opened blind slot is larger than the axial cross-sectional area of the negative coupling blind hole on the existing dielectric resonator, it can block the coupling of other dielectric resonators through the connection, thereby weakening the influence of parasitic coupling and obtaining a more symmetric frequency response characteristic. Description of the Drawings

[0013] Figure 1 It is a schematic diagram of the three-dimensional structure of an existing dielectric resonator;

[0014] Figure 2 is a schematic diagram of the three-dimensional structure of the first embodiment of the present invention;

[0015] Figure 3 is a schematic diagram of a top view of the structure of the first embodiment of the present invention;

[0016] Figure 4 It is a schematic diagram of the longitudinal section structure of the first embodiment of the present invention;

[0017] Figure 5 is a schematic cross-sectional structure diagram of the first embodiment of the present invention;

[0018] Figure 6 is a passband frequency response curve of an existing dielectric waveguide filter;

[0019] Figure 7 is a passband frequency response curve of a dielectric waveguide filter according to the first embodiment of the present invention;

[0020] Figure 8 yes Figure 6 and Figure 7 Comparison curve of passband frequency response of dielectric waveguide filters;

[0021] Fig. 9 is a structural diagram of Embodiment 2 of the present invention;

[0022] Fig.10 is a schematic diagram of a top view of the structure of the second embodiment of the present invention;

[0023] Fig.11 is a schematic diagram of the longitudinal structure of the second embodiment of the present invention;

[0024] Fig.12 is a frequency response comparison curve diagram of Embodiment 1 and Embodiment 2 of the present invention;

[0025] Fig.13 It is a frequency response comparison curve diagram of the first embodiment, the second embodiment and the existing dielectric waveguide filter in the present invention. DETAILED DESCRIPTION

[0026] A dielectric resonator coupling structure of the present invention comprises a dielectric resonator 1 and a dielectric resonator 2 connected to each other, that is, the dielectric resonator 1 and the dielectric resonator 2 are connected as a whole, a coupling structure is provided at a connection 5 between the dielectric resonator 1 and the dielectric resonator 2, and the coupling structure comprises an elongated blind groove 6, the blind groove 6 is opened at the connection 5 between the dielectric resonator 1 and the dielectric resonator 2, the length of the blind groove 6 is 40% to 100% of the length of the connection 5 between the dielectric resonator 1 and the dielectric resonator 2, and the depth of the blind groove 6 is 50% to 95% of the height of the connection 5 between the dielectric resonator 1 and the dielectric resonator 2.

[0027] The dielectric resonator 1 and the dielectric resonator 2 are both made of ceramic dielectric materials or polymer materials; the shapes of the dielectric resonator 1 and the dielectric resonator 2 are both circular or polygonal blocks, and square blocks are used in the embodiment of the present invention; a resonant blind hole 7 is provided at the center of the surface of the dielectric resonator 1 and the dielectric resonator 2, and the resonant blind hole 7 can be provided on the upper surface of the dielectric resonator, or on the lower surface of the dielectric resonator, or on the side of the dielectric resonator, and the depth of the resonant blind hole 7 is less than the depth of the blind groove 6.

[0028] A dielectric waveguide filter comprises a dielectric resonator negative coupling structure, which is specifically formed by connecting a plurality of dielectric resonators.

[0029] Embodiment 1

[0030] like Figure 2 to Figure 8 As shown, the blind groove 6 extends from one side of the connection 5 between the dielectric resonator 1 and the dielectric resonator 2, and does not penetrate the dielectric resonator. A distance is left between the wall of the blind groove 6 and the other side of the connection 5, which is equivalent to the length of the blind groove 6 being 80% of the length of the connection 5 between the dielectric resonator 1 and the dielectric resonator 2. The unseparated part on the connection 5 between the dielectric resonator 1 and the dielectric resonator 2 forms a coupling portion 8, and the coupling portion 8 is L-shaped, or can be said to be 7-shaped; the height of the horizontal portion of the coupling portion 8 is relatively low, and the height of the horizontal portion of the coupling portion 8 is not greater than half of the height of the connection 5 between the dielectric resonator 1 and the dielectric resonator 2, thereby forming a capacitive coupling window; the vertical portion of the L-shaped coupling portion 8 plays the role of a reinforcing rib to enhance the connection strength, which can avoid the problem that when the height of the horizontal portion of the coupling portion 8 is relatively small, the connected dielectric resonator 1 and the dielectric resonator 2 are easily broken at the connection 5.

[0031] Among them, adjusting the height and length of the horizontal part of the coupling part 8 can play a role in adjusting the negative coupling amount. Specifically, the longer the length and the higher the height, the stronger the negative coupling, and vice versa. Adjusting the height and length of the horizontal part of the coupling part 8, that is, adjusting the length and depth of the blind groove 6, the coupling between the dielectric resonator 1 and the dielectric resonator 2 is negative coupling. Adjusting the depth of the blind groove 6 can adjust the negative coupling amount. The deeper the blind groove 6, the weaker the coupling, and vice versa.

[0032] The L-shaped coupling portion 8 will also form a resonance peak on the filter curve of the dielectric waveguide filter, but the position of the resonance peak in the frequency domain can be controlled by adjusting the length of the horizontal portion of the coupling portion 8, and is not greatly affected by the height of the horizontal portion of the coupling portion 8. In addition, the area of ​​the coupling portion 8 is large, and the Q value of the series resonance effect formed is not high. Therefore, the resonance peak wave is low, and the influence on the suppression performance of the dielectric waveguide filter is small. The length of the horizontal portion of the coupling portion 8 can be adjusted first to move the resonance peak caused by the coupling portion 8 to a frequency band with low suppression requirements, and then the negative coupling amount can be adjusted by adjusting the height of the horizontal portion of the coupling portion 8, so as to ensure both the negative coupling amount and the dielectric waveguide filter performance meeting the suppression requirements; and because the blind slot 6 has a large cross-sectional area, it has a blocking effect on the coupling of other dielectric resonators through the connection 5, thereby weakening the parasitic coupling effect, and a more symmetrical frequency response characteristic can be obtained, which can greatly balance the suppression level of the low end and the high end of the passband, ensure the suppression margin, and improve the yield rate.

[0033] It can be seen that Figure 6 , 7 As shown in Figures 8 and 9, the dielectric waveguide filter proposed in the present invention has a lower resonance peak at the low frequency band on the left side of the passband and has better out-of-band suppression performance; near the passband (the passband refers to the frequency band with the smallest attenuation when the signal passes through the filter, that is, the frequency range of the signal allowed to pass by the filter), the frequency response curve of the dielectric waveguide filter proposed in the first embodiment of the present invention is more balanced and has better symmetry, which is conducive to balancing the suppression level of the low and high ends of the passband, ensuring the suppression margin, and improving the yield rate.

[0034] Figure 8 In the figure, the dashed line curve is the frequency response curve of the prior art, and the solid line is the frequency response curve of the first embodiment of the present invention.

[0035] Embodiment 2

[0036] like Fig. 9 , Fig.10 , Fig.11 As shown, the blind groove 6 extends upward from the bottom center of the connection 5 between the dielectric resonator 1 and the dielectric resonator 2, and the walls on both sides of the blind groove 6 are spaced apart from both sides of the connection 5 without lateral penetration to form a closed groove structure, which is equivalent to the length of the blind groove 6 being 80% of the length of the connection 5 between the dielectric resonator 1 and the dielectric resonator 2.

[0037] At the non-separated part on the connection 5 between dielectric resonator 1 and dielectric resonator 2, a coupling part 8 is formed. The coupling part 8 is in a "冂" shape. The height of the horizontal part of the coupling part 8 is relatively low, and the height of the horizontal part of the coupling part 8 is also less than half of the height of the connection 5 between dielectric resonator 1 and dielectric resonator 2, thus forming a capacitive coupling window. This "冂"-shaped coupling part 8 has a similar function to that in the first example. The vertical part of the coupling part 8 acts as a reinforcing rib to enhance the connection strength, which can more easily avoid the problem that when the height of the horizontal part of the coupling part 8 is small, the connected dielectric resonators 1 and 2 are prone to breakage at the connection 5.

[0038] Similar to the first example, the coupling between dielectric resonator 1 and dielectric resonator 2 is negative coupling. The height and length of the horizontal part of the coupling part 8 are both used to adjust the negative coupling amount. Specifically, the longer the length and the higher the height, the stronger the negative coupling, and vice versa. Adjusting the height and length of the horizontal part of the coupling part 8 is equivalent to adjusting the length and depth of the blind slot 6. The deeper the blind slot 6, the weaker the coupling, and vice versa.

[0039] Generally, the blind slot 6 is in the middle position of the connection 5 in the transverse direction. The distances from it to the left and right side walls of the dielectric resonator are equal, and it is in a "冂" shape. This is the difference in structure from the first example. Therefore, the length of the horizontal part of the coupling part 8 determines the transverse position and shape of the blind slot 6, that is, the length of the horizontal part of the coupling part 8. The function of this variable is similar to that in the first example.

[0040] The "冂"-shaped coupling part 8 also inevitably forms a resonance peak on the filtering curve. As mentioned above, similar to the first example, adjusting the length of the horizontal part of the coupling part 8 can adjust the frequency domain position of the resonance peak. The height of the horizontal part of the coupling part 8 has little influence on this. Similarly, the area of the coupling part 8 is relatively large, and the Q value of the formed series resonance effect is small. Therefore, the peak of the resonance peak is relatively low and will not deteriorate the suppression performance of the filter. Adhering to the same design optimization principle, first adjust the length of the horizontal part of the coupling part 8 to move the resonance peak to an irrelevant frequency domain without affecting the suppression index, and then adjust the height of the horizontal part of the coupling part 8 to make the near-end suppression index meet the customer requirements. Such a "冂"-shaped coupling part can expand the cross-sectional area of the blind slot 6, and can also resist the coupling effect between the dielectric resonators at the connection 5, reduce parasitic coupling, obtain a frequency response curve with better symmetry, and make the left and right suppression heights in the passband more balanced.

[0041] From Fig.12 It can be seen that near the passband, the balance and symmetry of the frequency response curves of the second example and the first example are basically the same. However, at the far-end suppression of the passband, the harmonic peak of the second example is farther from the passband, lower in height than the first example, with a better response effect and a larger suppression margin.

[0042] Fig.12In FIG. 1 , the solid line is the frequency response curve of the first embodiment of the present invention, and the dotted line is the frequency response curve of the second embodiment of the present invention.

[0043] Fig.13 The figure is a comparison of the three curves before and after. The solid line is the frequency response curve of Example 1, the dashed line is the frequency response curve of Example 2, and the bold dotted line is the passband frequency response curve of the existing dielectric waveguide filter. As can be seen from the figure, the balance of the frequency response curves of Example 1 and Example 2 of the present invention at the near end of the passband is basically the same, and both are better than the frequency response curves of the existing dielectric filter, and the symmetry is better. As for the resonance peak, the height of Example 1 and Example 2 of the present invention is lower than that of the existing dielectric filter, and the suppression margin is larger. In summary, Example 2 has the largest suppression margin, followed by Example 1.

[0044] In summary, the dielectric resonator coupling structure of the present invention can effectively reduce the influence of the resonance peak and parasitic coupling in the design, ensure the good balance and symmetry of the frequency response curve, solve the problem of insufficient suppression margin, and at the same time bring positive benefits, and can also improve the insertion loss and reduce the power consumption pressure of the communication system.

[0045] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0046] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A dielectric resonator negative coupling structure, comprising at least two connected dielectric resonators, wherein a coupling structure is provided at the connection between the dielectric resonators, characterized in that: The coupling structure includes an elongated blind groove, which is opened at the connection between the dielectric resonators. The length of the blind groove is 80% of the length of the connection between the dielectric resonators, and the depth of the blind groove is 50% - 95% of the height of the connection between the dielectric resonators; the material of the dielectric resonator is a polymer material; the shape of the dielectric resonator is circular or polygonal; the blind groove is opened at the middle position of the connection between the dielectric resonators, and there are distances left between the two side walls of the blind groove and the two sides of the connection to form a closed groove structure. The unseparated part on the connection between the dielectric resonators forms a coupling part, and the coupling part is in a shape of "冂"; the height of the horizontal part of the coupling part is not greater than half of the height of the connection between the dielectric resonators.

2. The dielectric resonator negative coupling structure according to claim 1, characterized in that: A resonant blind hole is provided at the center of the surface of each dielectric resonator, and the depth of the resonant blind hole is less than the depth of the blind groove.

3. The dielectric resonator negative coupling structure according to claim 1, characterized in that: The blind groove extends from one side of the connection between the dielectric resonators and does not penetrate the dielectric resonator. There is a distance left between the wall surface of the blind groove and the other side of the connection. The unseparated part on the connection between the dielectric resonators forms a coupling part, and the coupling part is in an L shape.

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