FI128047B - Frame structure for a RF filter and method producing the same - Google Patents

Abstract

The invention relates to a frame structure for an RF filter. The body structure is such that in addition to the first wall structure (WS1) and one or more resonators (R1-R6) extending from it in the direction of the second wall structure (WS2), the opposite second wall structure (WS2) and the joining structure (MW1) also -MW5; EW1- EW2) between the wall structures (WS1, WS2) the same integral piece in a part, and to this, the respective resonator (R1-R6) belongs to the same whole formed integrally by casting, injection molding or 3D printing as mentioned in the direction of both wall structures (WS1, WS2) and the joining structure (MW1-MW5; EW1-EW2) between them, and the respective resonator (R1-R6) extend in the body structure in the direction between said wall structures (WS1, WS2).

Description

Background of the Invention

RF filters, or radio frequency filters, are used, for example, in connection with RF equipment such as a transmitter, receiver or transceiver used in base stations of a cellular network, in particular amplifiers contained therein as filtering and matching circuits.

Resonator-type filters comprise a frame having one or more compartments whose shape is defined by the walls of the frame.

The section of the body structure may typically have an inner conductor extending from the bottom of the compartment or cavity, called a resonator or resonator pin, the common structure being a coaxial resonator wherein the inner conductor or resonator is coaxial or coaxial with the surrounding compartment or cavity. The walls of the compartment of the metal or conductively coated body structure and the metal or conductively coated inner conductor together form a resonant circuit. In more complex RF filters, the frame structure is multi-compartmented and each compartment has its own internal conductor, or resonator, to form a plurality of resonant circuits which, by appropriate coupling, provide the desired frequency responses, i.e., blocking bands and pass bands.

In prior art frame structures of RF filters, structural integration is not optimal and, due to the inaccuracy of manufacturing tolerances, causes problems in the use of the frame structure, i.e. the RF filter, such as inaccuracy of filter operation such as bypassing or blocking. The problems are exacerbated as the frequency bands rise further and higher, such as the 3.5 GHz bands.

Brief Description of the Invention

It is therefore an object of the invention to provide a novel type of RF filter body structure and manufacturing method so that the above problems can be solved or alleviated. The object of the invention is achieved by a frame structure and a method which are characterized by what is stated in the independent claims. Preferred embodiments of the invention are claimed in the dependent claims.

The invention is based on a novel structural integration and a method implementing it.

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An advantage of the frame structure and method according to the invention is the new type of structural integration and the better manufacturing accuracy it enables, which in turn provides a better frequency stabilization of the frame structure in use, such as an RF filter. The advantage is due to the fact that the surface of the body 5 structure, and in particular of the transverse resonators contained therein, is of high quality and not porous. According to one embodiment, the integration of the resonator hat ', i.e. the expansion of the resonator cross sectional area into the resonator and other structural assembly, still increases the degree of integration.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described in connection with preferred embodiments, with reference to the accompanying drawings, in which:

Figure 1 illustrates a frame structure before separating the ends of the resonators from another wall structure,

Figure 2 shows a frame structure in which the ends of the resonators are already separated from the other wall structure,

Figure 3 shows the frame structure and two cover plates closing the open sides thereof.

DETAILED DESCRIPTION OF THE INVENTION

Referring to Figures 1-3, this is a frame structure FR which is

For RF filter. The material of the frame structure FR is, for example, aluminum or magnesium. In order to improve electrical conductivity, the aluminum frame structure may, at the final stages of manufacture, be coated with a coating with better conductivity, such as silver.

The frame structure FR comprises a first wall structure WS1, a second second wall structure WS2 facing the first wall structure WS1 and an interconnection MW1-MW5 and / or EW1, EW2 connecting the wall structures WS1, WS2 to the wall structures WS1, WS2.

As noted above, there are two possibilities for the interconnection, either alternatively but preferably in one embodiment complementary, i.e. the interconnection comprises the end walls EW1, EW2 and / or the partitions MW1MW5, preferably both as in the examples of the figures.

In addition, the frame structure FR includes the resonator sections C1-C6 between the wall structures WS1, WS2, which are separated by the partitions MW1-MW5, and furthermore for forming the outermost sections C1 and C6.

20175200 prh 10-12-2018 Also participating in the end walls EW1, EW2. The compartments C1-C6 eventually close the separate side panel bodies SP1, SP2, or the like, covered by the open sides S1, S2 of the frame structure shown in Figure 3.

This is a frame structure of a resonator-type filter, so that there is a plurality of resonators R1-R6 extending from the first wall structure WS1 towards the opposite second wall structure WS2, such that the inductive end 1E1-1E6 of B1 is located at B1 of the resonator. the resonators R1-R6 are short-circuited to the first wall structure WS1, while the capacitive free end CE1-CE6 of the resonators is 10 closer to the opposite second wall structure WS2.

In addition to the first wall structure WS1 and the resonators R1-R6 protruding therefrom towards the second wall structure WS2, the opposite second wall structure WS2 and the interconnection between the wall structures WS1, WS2 of MW1-MW5 and / or EW1-EW2 pieces.

Thus, each resonator R1-R6 belongs to the same 1-part integral casting, injection molding, or injection molding or 3D printing both wall structures WS1, WS2 and the interconnection between them 20 MW1-MW5, EWent-E2 In the direction WS2, each resonator R1-R6 in the FR structure extends.

What is common to these manufacturing methods is that the material constituting the body structure flows forward and forms the desired shape. In molding and injection molding, the material is molten, in 3D printing, for example, molten material is molten to form the frame structure. In molding and injection molding, a molding machine with its mold can be used.

Later, the manufacturing method will be discussed in more detail, but already at this stage it can be noted that after the first stage of the manufacturing process, there is a structure of Fig. 1 in which the resonators (or resonator blanks in some way) are connected to the two long wall structures WS1, WS2. but also to the opposite, i.e. to the other wall structure WS2.

When the resonators R1-R6 (as if their preforms) are cut off, the re35 resonators R1-R6 have free ends, i.e. capacitive ends CE1-CE6, and thus the situation and structure of Fig. 2 are achieved.

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Such a structure is much better than the prior art structure in which the resonators rising from the bottom (which would be a first wall structure), and thus also towards the bottom, are a cover made of a separate body and not a wall of the same frame structure FR.

In the invention, the resonators are transverse, for example at right angles, to the direction between the cover plates SP1, SP2 enclosing the sides S1, S2 of the frame FR, but parallel to the direction of the wall structures WS1, 10 WS2. If the extension direction of the compartments C1-C6 is interpreted as being the direction between the separate cover plates SP1, SP2 enclosing the compartments C1-C6, then the resonators R1-R6 are transverse to the extension direction of the compartments C1-C6. In Figures 3, the cover plates SP1, SP2 can also be seen as the bottom and the cover, due to the position of the main body FR in Fig. 3. If the cover member FR in the position FR of Fig. 15 1-2 were mounted, they could be seen as side surfaces to the body FR.

In one embodiment, the capacitive end CE1-CE6 of one or more resonators R1-R6 has a widening CA1-CA6 increasing the cross-sectional area of the resonator to increase the capacitive coupling relative to the adjacent second wall structure WS2. It can be said that each widening CA1-CA6 together with the opposing wall structure WS2 forms as if a capacitor structure with the plate surfaces facing each other.

In this case, each widening CA1-CA6 belongs to the same 1-piece integral assembly formed by injection molding, injection molding or 3D printing with said resonator R1-R6 and the two facing structures WS1, WS2 and their interconnected MW1-MW5, EW1, EW1, EW1 each resonator R1-R6 of which in the intermediate direction of said wall structures WS1, WS2 extends along its extension CA1-CA6 in the frame structure FR.

By cutting off the resonators R1-R6, it is possible to achieve more than just the aforesaid circumstance, that is, the resonators R1-R6 formed by the free / capacitive ends CAI, CA2. Thus, in one embodiment, the resonators R1-R6 are cut, for example by milling, between those flaps CA1-CA6 and the other wall structure WS2,

20175200 prh 10-12-2018 For example, the cutting width is approximately equivalent to the width of the expansion wall such as CAI from the second wall structure WS2, since this removes the connecting base MP1 between the expansion wall such as CAI and the second wall structure WS2 and the surface of the wall structure WS2 towards the widening such as CAI is obtained smooth and smooth.

As discussed, the partitions MW1-MW5 and / or the end walls EW1, EW2 of the sections C1-C6 may be integral between the wall structures WS1, WS2.

Thus, in one embodiment, for separating the frame sections C1-C6, the frame FR comprises partitions MW1-MW5 extending between the first wall structure WS1 and the opposite second wall structure WS2, which are said interconnections connecting the first wall structure WS1 and the opposite wall WS12. Thus, in this embodiment, the partitions MW1-MW5 also belong to the same 1-piece integral casting, injection molding or 3D printing resonators R1-R6 extending in the direction MW1-MW5 of the said partitions and the two wall structures WS1 facing each other, in the direction of the resonate20, the R1-R6 frames in the FR structure extend.

Alternatively or additionally, the connecting structure may be the end walls EW1, EW2 of the ends of the frame structure. Thus, in one embodiment, the frame structure comprises end walls EW1, EW2, which are said interconnections connecting the first wall structure WS1 and the opposite second wall structure WS2, and the end walls are EW1, EW2 at the ends of the frame structure W1 and , and that these end walls EW1, EW2 also belong to the same 1-piece integral casting or 3D-printing set having both resonators R1-R6 extending in the direction of said end walls EW1, EW and both facing structures WS1, WS2 facing each other, in the direction, the resonators R1-R6 in the frame structure extend.

Comparing Figures 1-2, it can be seen that in Fig. 1 the resonators R1-R6 are also initially, i.e. in the initial stage of manufacture, not as a third type of interconnector, but according to Fig. 2, the resonators

20175200 prh 10-12-2018 the lane is disconnected from the other wall structure WS2, so that they no longer function as an interconnection between the wall structures WS1, WS2.

As discussed, to cover the open sides of the 1-piece body, the body comprises separate side-plate bodies SP1, SP2 or other similar cover bodies SP1, SP2, thus closing the sides of the body, S1, S2. Thus, those cover plates SP1, SP2 are encased in a 1-piece integral body member comprising a first wall structure WS1, an opposed second wall structure WS2, a connecting structure connecting the wall structures WS1, WS2 in the MW1-MW5, EW1-EW2, and R6 with extension CA1-CA6.

In one embodiment, the partitions have coupling openings 1R1-1R5, the size of which affects the interconnection of resonant circuits of adjacent compartments. Those coupling openings have also been formed during casting, injection molding or 3D printing, i.e. in practice the manufacturing15 method has determined the position and size of the shape of the leading edge of the coupling openings 1R1-1R5 in the partitions MW1-MW5.

Next, the manufacturing method is discussed. The frame structure can be secured by injection molding of a metal such as aluminum or magnesium, or the frame structure can be made by injection molding or injection molding of plastic, as long as the frame structure is coated with a conductive coating. It is also possible that 3D printing is used.

Metal casting such as die casting uses a die casting machine with a suitable mold. Injection molding of plastics uses injection molding machines with a suitable mold, and for printing of metals 3D25, the laser powder is melted by layers with the aid of a heated printing medium.

Thus, it is a method for manufacturing the RF filter body FR. In the method, a multi-compartmental frame FR comprising a first wall structure WS1, an opposed second wall structure WS2, an interconnecting structure MW1-MW5, EW1-EW2 and a plurality of resonators connecting said wall structures WS1, 30 WS2 is made.

According to an essential aspect of the method, the frame structure FR is molded, injection molded or 3D-printed into a 1-piece integral body such that the first wall structure WS, the opposite second wall structure 35 WS2, resonators R1-R6 extending in the direction between said wall structures

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MW5; EW1-EW2 belong to the same 1-piece integral part. 1 is not shown in the situation where resonators, such as resonator R1, are in contact with the first wall structure WS1, as well as with the second wall structure WS via bases such as base MP1.

Next, in the next step of the method, to form a capacitive end for each resonator R1-R6, each resonator is separated from the second wall structure WS2 by cutting off the resonators. Thus, the situation of Fig. 2 is achieved.

In order to improve the method and further increase the integrity of the body member, in one embodiment, the method is such that by casting, injection molding or 3D printing on each resonator R1-R6 in the same manner as described herein, a CA1-CA6 enlargement of the resonator cross-sectional area is formed.

Further, the method is such that for each resonator R1-R6 to form a capacitive end CE1-CE6, each resonator R1-R6 is cut off between each extension CA1-CA6 and the other wall structure WS2.

Thus, even a structure increasing the cross-sectional area of a resonator such as R1, i.e. a structure increasing capacitive coupling such as CAI, is associated with both its resonator R1 and the wall structures WS1, WS2 as well as the partitions MW1-MW5 and also the end walls EW1, EW2.

Further, it can be seen from the method that the method operates by casting or 3D-printing partitions (MW1-MW5) to interconnect the opposing wall structures (WS1, WS2) and extending in the direction of the resonators.

In addition, or alternatively, the method comprises operating in the opposite wall structures WS1, WS to interconnect and extending in the direction of the resonators, or 3D-printing the end walls EW1-EW2 at the ends of the frame structure.

The frame structure FR, for example in compartments CAI, CA6, may be provided with a signal input port and an output port, for example using apertures and signal conductors piercing the end walls EW1, EW2.

It will be obvious to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in many different ways. The invention and its embodiments are thus not limited to the examples described above, but may vary within the scope of the claims.

Claims (7)

A frame structure for an RF filter comprising a first wall structure (WS1), an opposite second wall structure (WS2) directed to the first wall structure, and between the wall structures (WS1, WS2) a unifying structure (MW1-MW5); EW1, EW2) joining the wall structures (WS1, WS2), the body structure comprising resonator compartments (C1-C6) in the area between the wall structures (WS1, WS2), and from the first wall structure (WS1) in the direction of the wall towards the wall (WS1) towards the wall resonators (R1-R6) extend, so that the respective inductive (IE1) end of the resonator (IE1-IE6) is on the same side as the resonator root (B1) where the resonator (R1) is short-circuited to the first wall structure (WS1) and The capacitive free end of the resonator (CE1-CE6) is closer to the opposite second wall structure (WS2), characterized in that in addition to the first wall structure (WS1) and the resonators (R115 R6) extending from the it in the direction of the second wall structure (WS2) also constitutes the opposite second wall structure (WS2) and the unifying structure (MW1-MW5; EW1-EW2) between the wall structures (WS1, WS2) the same integrate 1-piece, and thereby include the respective resonator (R1-R6) in the same 1-part integrate unit formed by casting, injection molding or 3D printing as both of said towards each other wall structures (WS1, WS2) and the unifying structure between them (MW1-MW5; EW1-EW2), the respective resonator (R1-R6) extending in the direction between said wall structures (WS1, WS2), and separating the compartments (C1-C6) of the body structure comprises the body structure partition walls (MW1-MW5) with coupling openings (IR1-IR5) extending between the first wall structure (WS1) and the opposite second wall structure (WS2), said intermediate walls forming which joins the first wall structure (WS1) and the opposite second wall structure (WS2), and that also the partitions (MW1-MW5) form part of the same 1-part integrate whole formed by casting, injection molding or 3D printing comprising both the resonators (R1-R6) extending in the direction of said partition walls (MW1-MW5) as both said facing wall structures (WS1, WS2) and the resonators (R1-R6) extending in the direction between them in the body structure. Frame structure according to claim 1, characterized in that in the capacitive end (CE1-CE6) of one or more resonators (R1-R6) 20175200 prh 09 -01- 2019 a width (CA1-CA6) which increases the cross-sectional area of the resonator in order to add a capacitive connection in relation to the second wall construction (WS2) and that the width (CA1-CA6) belongs to the same 1-part integral whole formed by casting, injection molding or 3D printing comprising the resonator 5 (R1-R6) and both said wall-facing structures (WS1), WS2) and the joining structure (MW1-MW5; EW1-EW2) between them, the respective resonator (R1-R6) having its width (CA1-CA6) extending in the direction between said wall structures (WS1, WS2) in the body structure. Frame structure according to any of the preceding claims 1- 2, characterized in that the body structure comprises end walls (EW1, EW2), which are said joining structures which join the first wall structure (WS1) and the opposite second wall structure (WS2), and That the end walls (EW1, EW2) are located at the ends of the body structure between the first wall structure (WS1) of the body structure and the opposite second wall structure (WS2), and that these end walls (EW1, EW2) also form in the same 1-part integral whole formed casting, injection molding or 3D printing, including both resonators (R1-R6) extending in the direction of the end walls (EW1, EW2) as both said wall-facing structures (WS1, WS2), the resonators (R1-R6) extends in the direction between them in the body structure. Body structure according to any of the preceding claims 1- 3, characterized in that as a blanket for the open sides of the body part 1 of the body structure, comprising the first wall structure (WS1), the opposite second wall structure (WS2), the joining structure (MW1-MW5; EW1-EW2) as joining the wall structures (WS1, WS2) and the resonators (R1-R6) extending in the direction between the wall structures (WS1, WS2), the body structure comprises separate side walls. 30 plate pieces (SP1, SP2) or other corresponding cover pieces (SP1, SP2). A method of producing an RF filter's body structure, in which a first wall structure (WS1), an opposite second wall structure (WS2), a joining structure (MW1-MW5; EW1-EW2) joining the said wall structures (WS1, WS2) are produced. ) and a body structure with several 35 compartments comprising resonators, characterized in that in the method: 20175200 prh 09 -01- 2019 - molded, injection molded or 3D printed, the frame structure into a 1-piece integral piece, such that the first wall structure (WS1), the opposite second wall structure (WS2), the resonators (R1-R 6) extending in the direction between said wall structures and said joint Structure (MW1-MW5; EW1-EW2) joining the wall structures (WS1, WS2) is contained in the same 1-piece integrate, and - in order to form a capacitive end for the respective resonator (R1-R6), the respective resonator is separated from the second wall structure (WS2) by cutting off the resonator, And that in the process be weighed in such a manner that as a unifying structure joining the opposite wall constructions (WS1, WS2) and extending in the direction of the resonators (R1-R6), the partitions (MW1- MW5) with coupling openings (IR1-IR5) which separate the compartments of the body structure. Method according to Claim 5, characterized in that a width (CA1-CA6) which is in the same connection with the respective resonator (R1-R6) is formed in the aforementioned manner by casting, injection molding or 3D printing, which width increases the cross-sectional area of the resonator. . Method according to claim 6, characterized in that in order In order to form a capacitive end for the respective resonator (R1-R6), the resonator is cut off between the respective width (CA1-CA6) and the second wall construction (WS2). Method according to any of the preceding claims 5-7, Characterized in that in the process gas is weighed in such a way that, as a joining structure joining the opposite wall constructions (WS1, WS2) and extending in the direction of the resonators, the end walls (EW1-EW2) are molded, injection molded. of the body structure.