JP2018195982A - Waveguide filter - Google Patents

Abstract

To provide a waveguide filter capable of achieving a stable filter property even if sealing surfaces are connected with screws.SOLUTION: A waveguide is formed with a conductive enclosure 1 and a conductive lid 2 attached so as to cover the enclosure 1. Inside the waveguide, irises 3 to form dielectric coupling windows are disposed to achieve a desired filtering property. The enclosure 1 and the lid 2 are secured with screws via a conductive plate-like member 4 which can be elastically deformed. A projection 5 protruding from the lid 2 side to the plate-like member 4 side is disposed between the lid 2 at a position to become a waveguide path 7 and the plate-like member 4. As the result, the projection 5 presses the plate-like member 4 to elastically deform the plate-like member 4 so as to reliably join the plate-like member 4 and the enclosure 1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a waveguide filter, and more particularly to a waveguide filter suitable for use in a wireless communication device or the like that operates in a high frequency region such as a microwave band.

  In general, a waveguide filter has a structure including an iris that forms a dielectric coupling window on the inner wall of a metal rectangular waveguide. For example, FIG. 3 shows an exploded perspective view of this type of waveguide filter. As shown in FIG. 3, a waveguide is formed by a conductive casing 1 and a conductive lid 2 that covers the top of the casing. An iris 3 forming a dielectric coupling window is arranged in the waveguide so as to have a desired filtering characteristic (Patent Document 1).

  In this type of waveguide filter, the filter characteristics deteriorate unless the bonded surfaces of the casing 1 and the lid 2 are sufficiently bonded. Therefore, generally, the housing 1 and the lid 2 are joined by brazing.

  On the other hand, in radio communication equipment, a waveguide filter is made of aluminum in order to reduce weight and cost. In some cases, a signal processing circuit is formed of a microstrip line and integrated with a waveguide filter. Therefore, high temperature processing such as brazing cannot be performed, and it is necessary to join the housing 1 and the lid 2 by screwing.

JP 2005-341350 A

  When the casing 1 and the lid 2 are joined by screws, contact failure may occur due to the flatness of the bonding surface, the number of screws, and the arrangement of the screws, and the filter characteristics may deteriorate. An object of the present invention is to provide a waveguide filter capable of solving such problems and obtaining stable filter characteristics even when bonding surfaces are joined by screws.

  To achieve the above object, the present invention forms a waveguide with a conductive casing and a conductive lid attached to cover the casing, and forms a dielectric coupling window in the waveguide. In the waveguide filter provided with the iris, a conductive elastically deformable plate member is disposed between the casing and the lid portion, and the lid portion and the plate shape in a region to be a waveguide are disposed. A convex portion protruding from the lid portion side to the plate-like member side is disposed between the member and the casing and the lid portion are screwed, so that the convex portion presses the plate-like member. Then, the plate member and the housing are joined by elastic deformation.

  In the waveguide filter of the present invention, an elastically deformable plate-like member is disposed between the casing and the lid portion, and the lid portion side to the plate-like member side between the lid portion and the plate-like member. By arranging the protruding part to protrude and screwing the housing and lid, the plate member and the housing can be securely joined by the elastic force of the plate member, and the filter characteristics are deteriorated. The structure is not invited. In particular, since the joining is performed by the elastic force of the plate-like member, the casing and the plate-like member are reliably joined even when vibration is applied to the waveguide filter or the temperature of the surrounding environment changes. Therefore, it is a waveguide filter suitable for a wireless communication device used in a severe usage environment.

  In addition, since reliable joining is possible by screwing instead of brazing, there is an advantage that it can be manufactured at low cost. Since it can be screwed, the lid can be disassembled for characteristic adjustment after assembly, which is excellent in that the yield of the manufacturing process can be improved.

  Furthermore, since reliable joining is possible by screwing, the housing and the lid can be made of aluminum, which is suitable for a wireless communication device from the viewpoint that the waveguide filter can be reduced in weight.

It is a figure explaining the Example of this invention. It is a figure explaining the Example of this invention. It is a disassembled perspective view of the conventional waveguide filter.

  The waveguide filter of the present invention forms a waveguide with a conductive casing and a conductive lid attached to cover the casing. An iris that forms a dielectric coupling window is arranged in the waveguide so as to have a desired filtering characteristic. The housing and the lid are screwed via a conductive elastically deformable plate-like member. Moreover, in this invention, the convex part which protrudes from the cover part side to the plate-shaped member side is arrange | positioned between the cover part and plate-shaped member of the position used as a waveguide. As a result, the convex portion presses the plate member, elastically deforms the plate member, and the plate member and the housing can be reliably bonded. Examples of the present invention will be described below.

  Examples of the present invention will be described. FIG. 1 shows a state in which a case 1 and a lid 2 of a waveguide filter described in the conventional example are joined by the method of the present invention, and shows a cross section passing through an iris 3 (a cross section in the left-right direction in FIG. 3). Yes. In FIG. 1, 1 is a housing made of aluminum, 2 is a lid portion made of aluminum, 3 is an iris forming a dielectric coupling window, 4 is a plate member made of aluminum, 5 is a convex portion, 6 is a screw, 7 Is a waveguide of a waveguide formed by the housing 1 and the plate-like member 4.

  As shown in FIG. 1, the present invention has a great feature in the joining structure of the housing 1 and the lid 2. That is, the convex portion 5 is disposed at a position that becomes the waveguide 7 between the housing 1 and the lid portion 2. The convex portion 5 may be integrated with the lid portion 2, or another member, for example, an aluminum tape may be attached to the lid portion 2. The convex portion 5 elastically deforms the plate-like member 4 constituting a part of the waveguide 7 when the housing 1, the plate-like member 4 and the lid portion 2 are joined by the screw 6, and the case 1 and A in FIG. The height, the width, the formation position, etc. are set so as to be surely joined at the position indicated by.

  Since FIG. 1 shows a cross-sectional view passing through the iris 3, the width of the waveguide 7 between the irises 3 arranged in the transmission direction of the microwave propagating through the waveguide 7 is wider than that shown in the figure. Even in this wide region, the convex portion 5 presses the plate-like member 4 to be elastically deformed, and can be reliably bonded to the housing 1 at a position corresponding to A in FIG.

  Since the plate-like member 4 is made of an elastically deformable material, shape, etc., even when vibration is applied to the waveguide filter or a temperature change occurs, a reliable bonding can be maintained by elastic deformation. .

  Further, as shown in FIG. 2, even by simply screwing at the corner portion of the waveguide filter, it is possible to surely bond even a portion (position indicated by B in the drawing) where a defective bonding is likely to occur.

  As described above, in the waveguide filter formed according to the present invention, the plate-like member 4 that can be elastically deformed is interposed between the housing 1 and the lid portion 2 and screwed so as to be pressed by the convex portion 5. As a result, a reliable bond can be formed, and deterioration of the filter characteristics due to poor contact can be prevented. Note that a portion of the waveguide 7 is deformed by the pressing of the convex portion 5, but the filter characteristics are not greatly affected.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, the elastically deformable member is not limited to aluminum, and may be another metal or a nonconductive plate-like member whose surface is coated with a conductive material. Moreover, the convex part 5 does not need to be electroconductive, What is necessary is just to be able to elastically deform the plate-shaped member 4.

1: casing, 2: lid, 3: iris, 4: plate-like member, 5: convex portion, 6: screw, 7: waveguide

Claims (1)

A waveguide filter comprising an iris that forms a waveguide by a conductive casing and a conductive lid attached to cover the casing, and forms a dielectric coupling window in the waveguide. ,
A conductive elastically deformable plate-like member is disposed between the casing and the lid portion, and the lid portion side between the lid portion and the plate-like member in a region to be a waveguide is formed from the lid portion side. By arranging a projecting portion protruding to the plate-like member side and screwing the housing and the lid portion, the projecting portion presses the plate-like member and elastically deforms the plate-like member and the A waveguide filter characterized by being joined to a housing.

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