阅读说明：本技术 一种高抑制小型化滤波器 (High-suppression miniaturized filter ) 是由 王文珠 佘文明 楼仲宇 于 2019-11-20 设计创作，主要内容包括：本发明实施例提供一种高抑制小型化滤波器,它包括介质基片和附着于介质基片上表面和下表面的金属镀层；所述介质基片被分隔成多个谐振腔,多个所述谐振腔连接形成滤波器主耦合通道；其中,至少一对非直接耦合的谐振腔间开设有耦合窗口,所述耦合窗口内的金属镀层上开设回形槽,所述回形槽两端分别延伸至耦合窗口两侧非直接耦合的两个谐振腔内。两个腔之间既存在正耦合又存在负耦合,非直接耦合腔之间窗口较小使得正耦合较小,由于设置回形槽,回形槽内的金属层与周围金属层独立未接触,从而形成负耦合零点。本发明能够通过设置负零点结构增强通带近端抑制,工艺实现简单且可靠性强。(The embodiment of the invention provides a high-inhibition miniaturized filter, which comprises a medium substrate and metal coatings attached to the upper surface and the lower surface of the medium substrate; the dielectric substrate is divided into a plurality of resonant cavities, and the resonant cavities are connected to form a filter main coupling channel; a coupling window is arranged between at least one pair of non-directly coupled resonant cavities, a circular groove is formed in a metal coating in the coupling window, and two ends of the circular groove respectively extend into the two non-directly coupled resonant cavities on two sides of the coupling window. The two cavities have positive coupling and negative coupling, the window between the indirect coupling cavities is small, so that the positive coupling is small, and the metal layer in the circular groove is independent and not in contact with the surrounding metal layer due to the arrangement of the circular groove, so that a negative coupling zero point is formed. The invention can enhance the near-end suppression of the passband by setting the negative zero point structure, and has simple process realization and strong reliability.)

1. A high-suppression miniaturized filter is characterized by comprising a medium substrate, wherein the upper surface and the lower surface of the medium substrate are plated with metal coatings; the dielectric substrate is divided into a plurality of resonant cavities, and the resonant cavities are connected to form a filter main coupling channel; a coupling window is arranged between at least one pair of non-directly coupled resonant cavities, a circular groove is formed in a metal coating in the coupling window, and two ends of the circular groove respectively extend into the two non-directly coupled resonant cavities on two sides of the coupling window.

2. The high rejection, miniaturized filter of claim 1 wherein said circular groove comprises a metal area without stripping of metal plating and a recessed area surrounding said metal area, said recessed area having a depth greater than or equal to a thickness of said metal plating to leak out of said dielectric substrate.

3. The high-rejection miniaturized filter of claim 1 wherein said circular grooves are formed on the upper and/or lower surfaces of said dielectric substrate.

4. The high rejection miniaturized filter of claim 1 wherein said loop-back grooves have a length L ≦ λ/2 and a width M ≦ M '/4, where λ is the wavelength and M' is the width of the corresponding resonator.

5. The high-rejection miniaturized filter of claim 1 wherein the two first and last resonant cavities of the main coupling channel of the filter are connected to the input terminal and the output terminal, respectively.

6. The high rejection, miniaturized filter of claim 1 wherein said recess regions and said metal regions are circular, polygonal or elliptical.

7. The high rejection, miniaturized filter of claim 6 wherein said recess region and said metal region are symmetric or asymmetric along said coupling window.

8. A manufacturing method of a high-suppression miniaturized filter is characterized in that a metal coating on a medium substrate is stripped through a laser, photoresist or machining method, and a circular groove with two ends extending to two indirectly coupled resonant cavities is formed, so that a negative zero point is formed between the resonant cavities.

9. The method of claim 8, wherein the functional characteristics of the filter include band pass, band reject, high pass, low pass, and their mutual duplexers, combiners, and multiplexers.

Technical Field

The embodiment of the invention relates to the technical field of communication, in particular to a high-rejection miniaturized filter.

Background

In a base station system for mobile communication, communication signals carrying communication data in a specific frequency range are generally transmitted through a transmitting antenna, and the communication signals are received through a receiving antenna. The signal received by the receiving antenna contains not only the communication signal carrying the communication data within the specific frequency range, but also a number of spurious or interfering signals outside the specific frequency range. To obtain the communication signal carrying communication data in a specific frequency range transmitted by the transmitting antenna from the signal received by the receiving antenna, the signal received by the receiving antenna is usually filtered by a filter to filter out clutter or interference signals outside the specific frequency of the communication signal carrying communication data.

With the rapid development of communication services and the increasing tension of radio frequency spectrum resources, higher requirements are put on the performance indexes of the filter, the insertion loss requirement is lower, the volume requirement is smaller, and the performance requirement is higher. In recent years, filters using dielectric substrates have been used in passive filters, which have high dielectric constant, high Q, and low temperature offset characteristics. How to satisfy higher frequency selectivity and out-of-band near-end rejection characteristics is a challenge for current filters.

The existing filter design is that an S-shaped groove or a 2-shaped groove is arranged between indirect coupling cavities, the inner side of the groove does not contain a metal part, the method needs to remove the S-shaped groove or the 2-shaped groove on an upper layer and a lower layer in a mirror image mode, and the processing difficulty and the structural complexity of the filter are greatly increased.

Disclosure of Invention

The embodiment of the invention provides a high-suppression miniaturized filter, which is used for solving the problems of processing difficulty and complex structure of the filter in the prior art.

In a first aspect, an embodiment of the present invention provides a high-rejection miniaturized filter, including a dielectric substrate, where an upper surface and a lower surface of the dielectric substrate are plated with a metal plating layer; the dielectric substrate is divided into a plurality of resonant cavities, and the resonant cavities are connected to form a filter main coupling channel; a coupling window is arranged between at least one pair of non-directly coupled resonant cavities, a circular groove is formed in a metal coating in the coupling window, and two ends of the circular groove respectively extend into the two non-directly coupled resonant cavities on two sides of the coupling window.

Preferably, the square groove comprises a metal area without stripping the metal coating and a groove area surrounding the metal area, and the depth of the groove area is greater than or equal to the thickness of the metal coating so as to leak out of the dielectric substrate.

Preferably, the circular groove is arranged on the upper surface and/or the lower surface of the medium substrate.

Preferably, the length L of the circular groove is less than or equal to lambda/2, and the width M of the circular groove is less than or equal to M '/4, wherein lambda is the wavelength, and M' is the width of the corresponding resonant cavity.

Preferably, the first resonant cavity and the last resonant cavity in the main coupling channel of the filter are respectively connected with the input end and the output end.

Preferably, the groove region and the metal region are circular, polygonal or elliptical.

Preferably, the recess region and the metal region are symmetrical or asymmetrical along the coupling window.

In a second aspect, an embodiment of the present invention provides a method for manufacturing a high-rejection miniaturized filter, including:

and stripping the metal coating on the dielectric substrate by using laser, photoresist or a machining method to form a circular groove with two ends extending into the two indirectly coupled resonant cavities so as to form a negative zero point between the resonant cavities.

Preferably, the functional characteristic package of the filter includes band pass, band stop, high pass, low pass and their formed duplexer, combiner, multiplexer.

According to the high-suppression miniaturized filter provided by the embodiment of the invention, in the filter main coupling channel structure formed by connecting a plurality of resonant cavities, a window is arranged between at least one pair of non-directly coupled resonant cavities, a metal coating in the window is provided with a circular groove, two ends of the circular groove respectively extend into the resonant cavities at two sides of the window, positive coupling and negative coupling exist between the two cavities, the positive coupling is smaller due to the smaller window between the non-directly coupled cavities, and two ends of a metal layer are not in contact with other metals due to the circular groove, so that a negative coupling zero point is formed.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a filter according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of another filter according to an embodiment of the invention;

FIG. 3 is a schematic diagram of another filter according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of another filter according to an embodiment of the present invention;

FIG. 5 is a schematic view of another arrangement position of the circular groove according to the embodiment of the invention;

FIG. 6 is a schematic diagram of a filter without a negative zero structure according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a simulation of a filter without a negative zero structure;

FIG. 8 is a schematic diagram of a filter according to an embodiment of the invention;

FIG. 9 is a schematic diagram of a simulation of a filter according to an embodiment of the invention;

FIG. 10 is a diagram of another filter according to an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

With the improvement of the performance requirement of the filter in the communication system, the high-power microwave filter at the base station end has the characteristics of high index, small volume and low cost. In implementing these high performance filters, limited by the cavity size, the filters need to be implemented using new materials or technologies. When the transmission frequency is high, a dielectric filter is selected to satisfy performance requirements such as loss and suppression. The transmission mode of the dielectric filter is the same as that of the metal waveguide filter, and is TE01 mode. But the dielectric filter has smaller volume and better loss than the metal waveguide filter.

The material characteristics of the limited and dielectric filters generally need to be added with transmission zeros when designing the filters. The dielectric filter of TE01 mode is more difficult to realize the negative coupling zero point than the metal waveguide filter. The traditional design introduces negative coupling zero through the change of the transmission mode of the resonant cavity or the change of the coupling polarity, simultaneously, the whole structure of the filter is more complicated or the size of the filter is increased, and a novel negative zero transmission coupling structure is needed.

Therefore, in the filter main coupling channel structure formed by connecting a plurality of resonant cavities (as indicated by the arrow in the figure), a loop-shaped groove is formed between at least one pair of non-directly coupled resonant cavities, and two ends of the loop-shaped groove respectively extend into two adjacent resonant cavities to form a negative zero point, so as to solve the problem that the overall structure of the filter is more complicated or the size of the filter is increased due to the fact that the negative coupling zero point is introduced by changing the transmission mode of the resonant cavities or changing the coupling polarity in the prior art. The following description and description will proceed with reference being made to various embodiments.

Fig. 1 is a schematic diagram of a filter according to an embodiment of the present invention, which includes a dielectric substrate, wherein the upper surface and the lower surface of the dielectric substrate are plated with a metal coating; the dielectric substrate is divided into a plurality of resonant cavities, and the resonant cavities are connected to form a filter main coupling channel; a coupling window is arranged between at least one pair of non-directly coupled resonant cavities, a circular groove is formed in a metal coating in the coupling window, and two ends of the circular groove respectively extend into the two non-directly coupled resonant cavities on two sides of the coupling window.

In this embodiment, as a preferred embodiment, the upper surface and the lower surface of the dielectric substrate 1 are attached with metal plating layers; the medium substrate 1 is also provided with a plurality of through holes 2, and the surface layers of the through holes 2 are attached with metal layers; the dielectric substrate 1 is divided into a plurality of resonant cavities 3 by the through holes 2, and the resonant cavities 3 are connected to form a filter main coupling channel; wherein, a return groove 4 is arranged between at least one pair of non-directly coupled resonant cavities 3, and two ends of the return groove 4 respectively extend into the two non-directly coupled resonant cavities 3.

In this embodiment, as shown in fig. 1, a top surface and a bottom surface of a dielectric substrate 1 are plated with metal coatings (such as a silver coating, a copper coating, etc.), meanwhile, a plurality of through holes 2 are formed on the dielectric substrate 1, a metal layer is deposited on a channel formed by the through holes 2 to conduct the upper and lower metal coatings, a plurality of through holes 2 form a metalized through hole array, the metalized through hole array surrounds a plurality of resonant cavities 3 on the dielectric substrate 1, the plurality of resonant cavities 3 are connected to form a filter main coupling channel, and a coupling window is formed between adjacent resonant cavities 3 in the figure to realize coupling connection between adjacent resonant cavities 3; at least one pair of adjacent resonant cavities 3 separated (not coupled and connected) by the through hole 2 is provided with a circular groove 4, the circular groove 4 replaces part of metalized through holes, and two ends of the circular groove 4 respectively extend into the two non-directly coupled resonant cavities 3 to form a negative zero point.

On the basis of the above embodiment, as a preferable implementation manner, the circular groove 4 includes a metal area without stripping the metal plating and a groove area surrounding the metal area, and the depth of the groove area is greater than or equal to the thickness of the metal plating to leak out of the dielectric substrate 1.

In this embodiment, as shown in fig. 1 to 4, the circular groove 4 includes a groove region and a metal region surrounded by the groove region, where the groove region is a closed-loop groove formed on the dielectric substrate 1, and is formed by stripping a metal plating layer in a region corresponding to the closed-loop groove to leak out of the dielectric substrate 1; the groove area is surrounded with a metal area, wherein the metal coating of the metal area part is not stripped. In the present embodiment, two longitudinal ends of the circular groove 4 extend into the two non-directly coupled resonant cavities 3, and preferably, the circular groove 4 is perpendicular to the array line formed by connecting the metalized through holes between the two resonant cavities 3 in the longitudinal direction.

In addition to the above embodiments, as a preferred embodiment, the circular groove 4 is provided on the upper surface and/or the lower surface of the dielectric substrate 1.

In this embodiment, as shown in fig. 4, the rectangular slot 4 is disposed on at least one side of the dielectric substrate 1, and may be disposed on a single side or both of the upper and lower sides.

As shown in fig. 5, the circular groove 4 may also be disposed between two other adjacent resonant cavities.

On the basis of the above embodiments, as a preferred implementation mode, the length L of the circular groove 4 is less than or equal to λ/2, and the width M of the circular groove 4 is less than or equal to M '/4, where λ is the wavelength and M' is the width of the corresponding resonant cavity 3.

In the embodiment, in order to make the effect of forming the negative zero point better, the length L of the circular groove 4 is less than or equal to λ/2, and the width M of the circular groove 4 is less than or equal to M '/4, where λ is the wavelength and M' is the width of the smaller one of the two corresponding resonant cavities 3.

On the basis of the above embodiments, as a preferred implementation manner, the first and the last two resonant cavities 3 in the main coupling channel of the filter are respectively connected to the input end and the output end.

On the basis of the above embodiments, as a preferable implementation mode, the circular groove 4 (the groove region and the metal region) is circular, polygonal or elliptical.

In the present embodiment, as a preferred embodiment, the rectangular or rounded rectangular slot 4 is shown in fig. 1 and 2.

In another embodiment, the rectangular slot 4 may also be a polygonal structure such as a triangle, a pentagon or a hexagon, or may also be an ellipse or a circle, an array line formed by connecting the metalized through holes between the two resonant cavities 3 is a resonant cavity wall, a length of the rectangular slot 4 perpendicular to the resonant cavity wall is not less than λ/2, and a length perpendicular to the resonant cavity wall is not less than M '/4, where λ is a wavelength, and M' is a width of a smaller one of the two corresponding resonant cavities 3.

In this embodiment, as still another preferred embodiment, as shown in fig. 3, the width of the metal region end portion in the rectangular groove 4 is larger than the width of the metal region middle portion, and the metal region end portion may be provided in a polygonal shape, a circular shape, or an elliptical shape, such as a rectangle provided with one end portion of the metal region in fig. 3.

On the basis of the above-described embodiments, as a preferred implementation, the circular groove 4 (groove region and metal region) is symmetrical or asymmetrical along the window.

In this embodiment, it is further preferred that the meandering slot 4 is symmetrical along the cavity wall.

In the above embodiments, adjacent may refer to adjacent and coupled to each other in the main coupling channel; the two non-directly coupled resonant cavities are two adjacent resonant cavities which are structurally but not directly coupled and connected outside the main coupling channel, as shown in fig. 1, the arrow direction in the figure indicates the main coupling channel, and the two resonant cavities along the arrow direction are respectively a first resonant cavity, a second resonant cavity, a third resonant cavity and a fourth resonant cavity, wherein the first resonant cavity and the second resonant cavity, the second resonant cavity and the third resonant cavity, and the third resonant cavity and the fourth resonant cavity are called as directly coupled or adjacent, and the first resonant cavity and the fourth resonant cavity are called as indirectly coupled or not adjacent; thus, the loop-shaped groove is provided between the first resonant cavity and the fourth resonant cavity.

As shown in fig. 6 and 7, the filter is a 5-cavity scheme, the passband frequency range is 37G-40GHz, and is a waveform diagram before the circular slot 4 is opened, and fig. 8 and 9 are waveform diagrams after the circular slot is opened according to the scheme of the embodiment of the present invention, it can be seen that the scheme of the embodiment of the present invention forms a zero point through the circular slot 4, and can effectively enhance the near-end rejection.

On the basis of the above embodiments, the dielectric substrates may be multiple layers, multiple layers of dielectric substrates are stacked, and a metal plating layer is also plated between adjacent dielectric substrates.

In a second aspect, an embodiment of the present invention provides a method for manufacturing a filter, including:

plating metal coatings on the upper surface and the lower surface of a medium substrate to divide the medium substrate into a plurality of resonant cavities, wherein the resonant cavities are connected to form a filter main coupling channel;

a coupling window is arranged on a metal coating between at least one pair of non-directly coupled resonant cavities, a return groove is arranged on the metal coating in the coupling window, and two ends of the return groove extend into two adjacent resonant cavities to form a negative zero point.

In the present embodiment, as a preferred embodiment, the length L of the circular groove is less than or equal to λ/2, and the width M of the circular groove is less than or equal to M '/4, where λ is the wavelength and M' is the width of the corresponding resonant cavity.

In this embodiment, as a preferred embodiment, the forming of the returning groove on the metal plating layer between at least one pair of non-directly coupled resonators specifically includes:

and stripping the metal coating on the medium substrate by using a laser, photoresist or machining method to form a resonant cavity wall formed by penetrating through metallization, wherein two ends of the resonant cavity wall extend to the loop-shaped grooves in the two indirectly coupled resonant cavities, and the loop-shaped grooves replace through holes at corresponding positions between the two indirectly coupled resonant cavities to form negative zero points between the resonant cavities.

On the basis of the above embodiments, as shown in fig. 10, as another preferred embodiment, the dielectric substrate may be further divided into a plurality of resonant cavities by a form of a slot instead of a through hole, and the embodiments of other features are the same as those of the above embodiments, and therefore, the description thereof is omitted.

According to the high-suppression miniaturized filter provided by the embodiment of the invention, in the filter main coupling channel structure formed by connecting a plurality of resonant cavities, a window is arranged between at least one pair of non-directly coupled resonant cavities, a metal coating in the window is provided with a circular groove, two ends of the circular groove respectively extend into the resonant cavities at two sides of the window, positive coupling and negative coupling exist between the two cavities, the positive coupling is smaller due to the smaller window between the non-directly coupled cavities, and two ends of a metal layer are not in contact with other metals due to the circular groove, so that a negative coupling zero point is formed.

The above-described embodiments of the apparatus are merely illustrative, and the units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.