Band-pass filter

Abstract

The invention discloses a band-pass filter, and the filter comprises a dielectric main body which comprises an open surface and a short-circuit surface which are oppositely disposed, and side surfaces disposed 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 invention, the tuning hole is formed in the dielectric 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] The present invention relates to the field of filters, and in particular to a bandpass filter. Background Art

[0002] Dielectric filters are constructed through coupling between dielectric resonant cavities. Dielectric resonator filters have high Q values, low insertion loss, small size and light weight. They 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 frequency bands. The current ceramic dielectric filter has poor far-end suppression capability and generally generates harmonics at twice the center frequency.

[0004] In order to improve the far-end suppression capability, the general practice is to make a separate filter or add an external shielding cover or a low-pass filter to push the harmonics to the far end, but this method has limited pushing capability. At the same time, this method may also have problems such as complex process or poor insertion loss performance. Summary of the invention

[0005] With regard to the background technology, the present invention aims to provide a bandpass filter which forms a zero point at the far end, thereby significantly improving the far end suppression capability, so as to improve the above-mentioned problem.

[0006] An embodiment of the present invention provides a bandpass filter, comprising:

[0007] The dielectric body comprises an open surface and a short-circuit surface arranged opposite to each other, and side surfaces arranged around the open surface and the short-circuit surface; the side surfaces comprise a main electrode surface and a top surface opposite to the main electrode surface;

[0008] A plurality of resonant through holes are arranged in the dielectric body and penetrate the dielectric body along the open surface and the short-circuit surface;

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

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

[0011] Preferably: the side surface also includes a side electrode surface, the main electrode surface and the side electrode surface are jointly 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 through hole.

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

[0013] Preferably, the metal covering layer is covered on the dielectric body by a metallization process, and the metallization process is a silver immersion process, a printing process or a silver spraying process.

[0014] Preferably, the metal loading layer is made by laser engraving a metal silver covering layer 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 dielectric body vertically or obliquely.

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

[0018] The bandpass filter proposed in the present invention forms a zero point at the far end where harmonics originally existed by arranging a tuning hole on the dielectric body and opening one end of the tuning hole, thereby significantly improving the filter's far end suppression capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a first isometric view of a bandpass filter provided by an embodiment of the present invention;

[0020] Figure 2 is a second isometric view of the bandpass filter provided by an embodiment of the present invention;

[0021] Figure 3 is a third isometric view of the bandpass filter provided by an embodiment of the present invention;

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

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

[0024] The markings in the accompanying drawings are: dielectric body 1, open surface 2, short-circuit surface 3, metal covering layer 4, main electrode surface 5, side electrode surface 6, top surface 7, metal loading layer 8, input and output electrodes 9, resonant through hole 10, tuning hole 11, and open circuit 12. DETAILED DESCRIPTION

[0025] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] See also Figures 1 to 3 , an embodiment of the present invention provides a bandpass filter, comprising:

[0027] The dielectric body 1 includes an open surface 2 and a short-circuit surface 3 arranged opposite to each other, and side surfaces arranged around the open surface 2 and the short-circuit surface 3; the side surfaces include 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 manufactured by dry pressing or injection molding followed by firing.

[0029] Particularly, in this embodiment, the dielectric body 1 is made of ceramic, whose dielectric constant is 45, and is produced by dry pressing and then firing.

[0030] In this embodiment, the surface of the dielectric body 1 is wrapped with a metal covering layer 4; the metal covering layer 4 can be covered on the dielectric body through a metallization process, and the metallization process can be a silver immersion process, a printing process or a silver spraying process.

[0031] Particularly, the metal covering layer 4 is a metal silver layer coated on the dielectric body 1 through an immersion silver metallization process.

[0032] A plurality of resonant through holes 10 are disposed in the dielectric body 1 and penetrate the dielectric body 1 along the open surface 2 and the short-circuit surface 2 .

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

[0034] The metal layer is covered in the resonant through hole 10 by a metallization process. The metal loading layer 8 can be made by laser engraving a metal silver covering layer or printing a metal layer.

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

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

[0037] In this embodiment, the tuning hole 11 is located between a plurality of resonant through holes 10, such as between two resonant through holes 10, and its cross-sectional shape may be circular, square, regular hexagonal or other shapes, which is not specifically limited in the present invention.

[0038] In addition, the tuning hole 11 may penetrate the dielectric body 1 vertically or obliquely, and these solutions are within the protection scope of the present invention.

[0039] In this embodiment, the shape of the open circuit is a circular ring pattern or other open circuit patterns, which is not specifically limited in the present invention.

[0040] In this embodiment, in particular, the side surface also includes a side electrode surface 6, the main electrode surface 5 and the side electrode surface 6 are jointly provided with an input-output electrode 9, the top surface 7 is provided with a metal loading layer 8, the input-output electrode 9 is connected to the metal loading layer 8, and forms a capacitive coupling with the metal layer of the adjacent resonant through hole 10.

[0041] The bandpass filter proposed in the present invention forms a zero point at the far end where harmonics originally existed by setting a tuning hole 11 on the dielectric body 1 and opening one end of the tuning hole 11, thereby significantly improving the filter's far end suppression capability.

[0042] The effects of the present invention will be described below with some examples.

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

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

[0045] according to Figure 5 and Figure 4 Comparing the waveforms, since this embodiment generates an additional zero point at the far end, the suppression (absolute value) of the far end 5000 MHz is improved by about 40 dB compared with the far end 5000 MHz suppression of the conventionally designed bandpass filter, and the suppression from the frequency range of 3000 MHz to 6800 MHz is better than that of the conventionally designed bandpass filter.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, it should be understood by those skilled in the art that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bandpass filter, characterized in that: include: The dielectric body comprises an open surface and a short-circuit surface arranged opposite to each other, and side surfaces arranged around the open surface and the short-circuit surface; the side surfaces comprise a main electrode surface and a top surface opposite to the main electrode surface; A plurality of resonant through holes are arranged in the dielectric body and penetrate the dielectric body along the open surface and the short-circuit surface; The tuning hole penetrates the dielectric body along the main electrode surface and the top surface and is located between the resonant through holes. A metal layer is provided in 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 dielectric body is wrapped with a metal covering layer; a metal layer is arranged in the resonant through hole, and a metal loading layer of a specific shape is arranged at the open surface 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 jointly 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 through hole.

4. The bandpass filter according to claim 1, characterized in that: The dielectric body 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 covering layer is covered on the dielectric body by a metallization process, and the metallization process is a silver immersion process, a printing process or a silver spraying process.

6. The bandpass filter according to claim 3, characterized in that: The metal loading layer is made by laser engraving a metallic silver cover layer 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 dielectric body vertically or obliquely.

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 to 9, characterized in that: The open circuit is disposed on the top surface.

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