Band-pass filter

Abstract

The utility model discloses a band-pass filter, comprising a medium main body comprising an open surface and a short-circuit surface which are oppositely arranged, and side surfaces arranged at the peripheries of the open surface and the short-circuit surface; the side surface comprises a main electrode surface and a top surface opposite to the main electrode surface; the plurality of resonance through holes are formed in the dielectric main body and penetrate through the dielectric main body along the open surface and the short circuit surface; and the tuning hole penetrates through the dielectric main body along the main electrode surface and the top surface and is located between the resonance through holes, a metal layer is arranged in the tuning hole, and an open circuit is formed at one end of the tuning hole. According to the utility model, the tuning hole is arranged on the medium main body, meanwhile, the open-circuit pattern is arranged at one end of the tuning hole, and a zero point is formed at a far-end place where harmonic waves originally exist, so that the far-end suppression capability of the filter is remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of filters, specifically to a bandpass filter. Background Technology

[0002] Dielectric filters are constructed by coupling between dielectric resonant cavities. Dielectric resonator filters have high Q values, low insertion loss, small size, and light weight, and are widely used in routers, wireless base stations, satellite communications, navigation systems, electronic countermeasures and other systems.

[0003] In communication systems, there is often a requirement for mutual signal isolation and suppression between different frequency bands. Current ceramic dielectric filters have poor far-end suppression capabilities, and harmonics are generally generated at twice the center frequency.

[0004] To improve far-end suppression capability, the common approach is to manufacture a split filter, add an external shield, or add a low-pass filter to push harmonics further away. However, this approach has limited pushing capability and may also have problems such as complex manufacturing process or deterioration of insertion loss performance. Utility Model Content

[0005] In view of the background technology, the purpose of this utility model is to provide a bandpass filter that forms a zero at the far end, thereby significantly improving the far-end suppression capability, so as to improve the above-mentioned problems.

[0006] This utility model embodiment provides a bandpass filter, which includes:

[0007] The medium body includes an open surface and a short surface disposed opposite to each other, and a side surface disposed around the periphery of the open surface and the short surface; the side surface includes a main electrode surface and a top surface opposite to the main electrode surface;

[0008] Multiple resonant through holes are disposed within the dielectric body and penetrate the dielectric body along the open surface and short path.

[0009] A tuning hole extends through the dielectric body along the main electrode surface and the top surface, and is located between the resonant through-hole. A metal layer is provided inside the tuning hole, and an open circuit is formed at the top surface.

[0010] Preferably, the surface of the dielectric body is covered with a metal covering layer; a metal layer is provided inside the resonant through hole, and a metal loading layer of a specific shape is provided at the open end of the resonant through hole.

[0011] Preferably, the side surface further includes a side electrode surface, the main electrode surface and the side electrode surface are provided with input and output electrodes, the top surface is provided with a metal loading layer, the input and output electrodes are connected to the metal loading layer and form capacitive coupling with the metal layer of the adjacent resonant via.

[0012] Preferably, the dielectric material is a dielectric material with a dielectric constant ranging from 3 to 150.

[0013] Preferably, the metal coating layer is applied to the substrate by a metallization process, which may be an immersion silver process, a printing process, or a spray silver process.

[0014] Preferably, the metal loading layer is made by laser engraving a metallic silver overlay or printing a metal layer.

[0015] Preferably, the cross-sectional shape of the tuning hole is circular, square, hexagonal, or other shapes.

[0016] Preferably, the tuning hole penetrates the medium body vertically or obliquely.

[0017] Preferably, the open circuit is in the shape of a circular ring pattern.

[0018] The bandpass filter proposed in this invention creates a zero point at the far end where harmonics would normally exist by setting a tuning hole on the dielectric body and setting one end of the tuning hole to be open-circuited, thereby significantly improving the filter's far-end suppression capability. Attached Figure Description

[0019] Figure 1 This is a first isometric view of the bandpass filter provided in this embodiment of the present invention;

[0020] Figure 2 This is a second isometric view of the bandpass filter provided in this embodiment of the present invention;

[0021] Figure 3 This is a third axonometric view of the bandpass filter provided in this embodiment of the present invention;

[0022] Figure 4 This is the electrical waveform diagram of an existing bandpass filter;

[0023] Figure 5 This is an electrical waveform diagram of the improved far-end suppression of the bandpass filter provided in this embodiment of the present invention;

[0024] The markings in the attached diagram are as follows: 1. Dielectric body; 2. Open surface; 3. Short surface; 4. Metal cover layer; 5. Main electrode surface; 6. Side electrode surface; 7. Top surface; 8. Metal loading layer; 9. Input and output electrodes; 10. Resonant via; 11. Tuning hole; 12. Open circuit. Detailed Implementation

[0025] To make the technical problem to be solved, the technical solution, and the beneficial effects of this utility model clearer and more understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0026] Please see Figures 1 to 3 This utility model embodiment provides a bandpass filter, which includes:

[0027] The medium body 1 includes an open surface 2 and a short surface 3 disposed opposite to each other, and a side surface disposed around the periphery of the open surface 2 and the short surface 3; the side surface includes a main electrode surface 5 and a top surface 7 opposite to the main electrode surface 5.

[0028] In this embodiment, the dielectric body 1 is a dielectric material with a dielectric constant ranging from 3 to 150, and can be obtained by dry pressing or injection molding followed by firing.

[0029] In particular, in this embodiment, the ceramic of the medium body 1 has a dielectric constant of 45 and is obtained by dry pressing and firing.

[0030] In this embodiment, the surface of the medium body 1 is covered with a metal coating layer 4; the metal coating layer 4 can be applied to the medium body by a metallization process, which can be an immersion silver process, a printing process, or a spray silver process.

[0031] Specifically, the metal overlay 4 is a silver layer coated onto the medium body 1 by an immersion silver metallization process.

[0032] Multiple resonant through holes 10 are disposed within the dielectric body 1 and penetrate the dielectric body 1 along the open surface 2 and the short surface 2.

[0033] In this embodiment, the number of resonant through holes 10 is at least two. The resonant through holes 10 penetrate the medium body 1 along the open surface 2 and the short surface 2, and are provided with a metal layer inside. A metal loading layer 8 of a specific shape is provided at the end of the open surface 2.

[0034] The metal layer is formed within the resonant via 10 using a metallization process. The metal loading layer 8 can be fabricated by laser engraving a silver overlay or printing a metal layer.

[0035] Specifically, in this embodiment, the number of resonant through-holes 10 is two.

[0036] Tuning hole 11 extends through the dielectric body along the main electrode surface 5 and the top surface 7, and is located between the resonant through hole 10. The tuning hole 11 has a metal layer inside and an open circuit 12 is formed at one end.

[0037] In this embodiment, the tuning hole 11 is located between multiple resonant through holes 10. For example, if it is located between two resonant through holes 10, its cross-sectional shape can be circular, square, hexagonal, or other shapes. This utility model does not make any specific limitations.

[0038] Furthermore, the tuning hole 11 can penetrate the medium body 1 vertically or obliquely, and these solutions are all within the protection scope of this utility model.

[0039] In this embodiment, the shape of the open circuit is a circular pattern or other open circuit pattern, and this utility model does not make any specific limitation.

[0040] In this embodiment, the side surface further includes a side electrode surface 6. The main electrode surface 5 and the side electrode surface 6 are provided with input and output electrodes 9. The top surface 7 is provided with a metal loading layer 8. The input and output electrodes 9 are connected to the metal loading layer 8 and form capacitive coupling with the metal layer of the adjacent resonant via 10.

[0041] The bandpass filter proposed in this utility model significantly improves the filter's far-end suppression capability by setting a tuning hole 11 on the dielectric body 1 and setting one end of the tuning hole 11 to be open-circuited. This creates a zero point where there were originally harmonics at the far end.

[0042] The following examples will illustrate the effects of this utility model.

[0043] like Figure 4 As shown, Figure 4 This is a waveform diagram of a conventionally designed bandpass filter, from... Figure 4 As can be seen, the insertion loss (absolute value) within the 2460MHz-2540MHz passband ranges from 0.9dB to 1.1dB. The rejection (absolute value) at the near-high frequency end of 3000MHz is 23.23dB, and the rejection (absolute value) at the far-high frequency end of 3600MHz is 22.62dB. At the far-high frequency end of 5000MHz, due to the generation of harmonics, such as... Figure 4 As shown, its suppression (absolute value) is 0.4dB, close to 0dB.

[0044] like Figure 5 As shown, Figure 5 This is a waveform diagram of the bandpass filter according to an embodiment of this utility model. Figure 5As can be seen, the insertion loss (absolute value) in the 2460MHz-2540MHz passband ranges from 0.9dB to 1.1dB, the rejection (absolute value) at the near end of the high frequency 3000MHz is 35.33dB, the rejection (absolute value) at the far end of the high frequency 3600MHz is 41.18dB, and the rejection (absolute value) at the far end of the high frequency 5000MHz is 40.19dB.

[0045] according to Figure 5 and Figure 4 Waveform comparison shows that, due to the additional zero point generated at the far end in this embodiment, the suppression (absolute value) at the far end of 5000MHz is improved by about 40dB compared to the far end of 5000MHz suppression of a conventional bandpass filter. The suppression in the frequency range of 3000MHz-6800MHz is also better than that of a conventional bandpass filter.

[0046] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A bandpass filter, characterized in that, include: The medium body includes an open surface and a short surface disposed opposite to each other, and a side surface disposed around the periphery of the open surface and the short surface; the side surface includes a main electrode surface and a top surface opposite to the main electrode surface; Multiple resonant through holes are disposed within the dielectric body and penetrate the dielectric body along the open surface and short path. A tuning hole extends through the dielectric body along the main electrode surface and the top surface, and is located between the resonant through-hole. A metal layer is provided inside the tuning hole, and an open circuit is formed at one end.

2. The bandpass filter according to claim 1, characterized in that: The surface of the medium body is covered with a metal covering layer; a metal layer is provided inside the resonant through hole, and a metal loading layer of a specific shape is provided at the open end of the resonant through hole.

3. The bandpass filter according to claim 2, characterized in that: The side surface also includes a side electrode surface. The main electrode surface and the side electrode surface are provided with input and output electrodes. The top surface is provided with a metal loading layer. The input and output electrodes are connected to the metal loading layer and are capacitively coupled with the metal layer of the adjacent resonant via.

4. The bandpass filter according to claim 1, characterized in that: The medium is a dielectric material with a dielectric constant ranging from 3 to 150.

5. The bandpass filter according to claim 2, characterized in that: The metal coating layer is applied to the substrate through a metallization process, which may be an immersion silver process, a printing process, or a spray silver process.

6. The bandpass filter according to claim 3, characterized in that: The metal loading layer is made by laser engraving a metallic silver overlay or printing a metal layer.

7. The bandpass filter according to claim 1, characterized in that: The cross-sectional shape of the tuning hole is circular, square, or hexagonal.

8. The bandpass filter according to claim 1, characterized in that: The tuning hole penetrates the medium body vertically or at an angle.

9. The bandpass filter according to claim 1, characterized in that: The open circuit is in the shape of a circular ring pattern.

10. The bandpass filter according to any one of claims 1-9, characterized in that: The open circuit is located on the top surface.

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