JPH069205U - Dielectric filter - Google Patents

Abstract

(57) [Abstract] [Purpose] To stabilize the attachment position of the combined substrate to the spacer and reduce the variation in filter characteristics. [Structure] The dielectric coaxial resonators θ1 to θ3 are connected in series by connecting to a coupling substrate 7 to form a filter circuit. The combined substrate 7 is supported with a spacer 8 spaced apart from the case 9 by a predetermined distance. A resist 11 is provided on the surface of the spacer 8 to attach positions A and A'of the combined substrate 7.
Is formed, and both ends of the combined substrate 7 are attached at the mounting positions A and A '.
Is attached to the surface of the spacer 8.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a dielectric filter in which a plurality of dielectric coaxial resonators are connected in series via a coupling substrate, and more particularly to a spacer interposed between the coupling substrate and one surface of a case.

[0002]

[Prior art]

 FIG. 6 is a perspective view of an essential part showing the internal structure of a conventional dielectric filter. The dielectric filter 20 shown in the figure is a quarter of a terminal short circuit in which the outer peripheral surface and the inner peripheral surface of a cylindrical dielectric made of ceramics or the like, excluding one end surface, are covered with a conductive member (dotted part). The case 25 has a filter unit in which the wavelength dielectric coaxial resonators θ11, θ12, and θ13 are connected in series via the coupling substrate 21. A coupling circuit composed of a plurality of electrodes d1 is formed on the front and back surfaces of the coupling substrate 21, and the central conductor on the open end face side of the dielectric coaxial resonators θ11 to θ13 is coupled via the coupling terminals T11 to T13. 21 to the corresponding electrode d1.

A spacer 22 made of an insulating substrate piece is attached to the lower surface of the combined substrate 21 so as to support the combined substrate 21 at a predetermined distance from the inner surface of the case 25. The spacer 22 has a longer dimension in the longitudinal direction than the combined substrate 21, and the combined substrate 21 and the terminals 23 and 24 are connected to the electrodes d2 formed at both ends of the surface.

[0004]

[Problems to be solved by the device]

 The spacer 22 of the conventional dielectric filter 20 is formed such that the dimension in the longitudinal direction is longer than that of the combined substrate 21, and there is a problem that variations in the filter characteristics become large due to the displacement of the mounting position of the combined substrate 21 with respect to the spacer 22. is there. Further, it is difficult to align the bonding substrate 21 on the surface of the spacer 22, which complicates the assembly work of the dielectric filter.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a dielectric filter in which a displacement of a mounting position of a coupling substrate with respect to a spacer is reduced and variation in filter characteristics is small.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a dielectric filter in which a spacer composed of a dielectric substrate is interposed between a coupling substrate for connecting a plurality of dielectric coaxial resonators in cascade and one surface of a case. A mark is formed on the surface to indicate the mounting position of the combined substrate.

[0007]

[Action]

 According to the present invention, the combined substrate is attached to a predetermined position of the spacer in accordance with the mark formed on the surface of the spacer, thereby preventing the combined substrate from being attached to the spacer. As a result, the mounting position of the combined substrate with respect to the spacer is stabilized, and variations in the filter characteristics are reduced.

[0008]

【Example】

 FIG. 1 is an exploded perspective view showing the structure of a dielectric filter according to the present invention. The dielectric filter 1 shown in the figure is a bandpass filter (hereinafter referred to as BPF) having a three-stage structure in which the dielectric coaxial resonators θ1 to θ3 shown in FIG. And output terminals are connected to terminals 2 and 3 via external coupling capacitors C1 and C4, respectively.

The dielectric filter 1 includes an internal filter unit including dielectric coaxial resonators θ1 to θ3, a coupling substrate 7, a spacer 8 and terminals 2 and 3, and a case 9 and a cover 10 which form a metal box body for housing the internal filter unit. It consists of

The dielectric coaxial resonators θ1 to θ3 are quarter-wave coaxial resonators with short-circuited terminations, and are made of, for example, 2.5 mm square prismatic ceramics or the like with a hole 5 formed on the central axis. The outer peripheral surface and the inner peripheral surface of the body 4 excluding one end surface are covered with a conductive member 6 (dotted portion) made of silver, copper or the like.

The capacitors C2 and C3 are formed by connecting electrodes D1, D2 and D3 to each other on the surface of a rectangular dielectric substrate 7. Further, electrodes are formed on the back surface of the combined substrate 7 at positions facing the electrodes D 1 and D 3, respectively, and the capacitor C 1 is formed by the electrode D 1 and the back surface electrode, and the capacitor C 4 is formed by the electrode D 3 and the back surface electrode. Are formed. Then, the coupling substrate 7 is arranged in front of the open end faces of the dielectric coaxial resonators θ1 to θ3, the electrodes D1 to D3 formed on the surface of the coupling substrate 7 and the central conductors of the dielectric coaxial resonators θ1 to θ3. (The inner peripheral surface of the hole 5 covered with the conductive member 6) is connected to the coupling terminals T1 to T3, respectively. A spacer 8 made of a dielectric substrate made of glass epoxy or the like is provided on the lower surface of the combined substrate 7, and the spacer 8 supports the combined substrate 7 at a predetermined distance from the inner surface of the case 9. ing.

The spacer 8 has a rectangular shape having substantially the same width dimension as the combined substrate 7, and has a longer dimension in the longitudinal direction than the combined substrate 7. At both ends of the surface of the spacer 8, rectangular electrodes D4 and D5 are formed as shown in FIG. 2, and a resist 11 indicating the attachment positions A and A'of the combined substrate 7 is formed. Further, an electrode (not shown) for connection is formed on the back surface of the spacer 8.

The electrodes D 4 and D 5 also function as the attachment electrodes of the combined substrate 7 and the attachment electrodes of the terminals 2 and 3. The combined substrate 7 has its both end edges aligned with the A and A'ends of the resist 11, respectively, and connects the back surface electrodes forming the capacitors C1 and C4 and a part of the electrodes D4 and D5 to the spacer. It is attached to the surface of 8. Further, terminals 2 and 3 are attached to other portions (portions surrounded by the resist 11) of the electrodes D4 and D5.

Then, the internal filter unit is housed in the case 9, and a part of the lower side surface of the dielectric coaxial resonators θ 1 to θ 3 and the connection electrode on the back surface of the spacer 8 are soldered to the case 9, for example, by soldering. After fixing and grounding the internal filter unit by connecting them with each other, the cover 10 is covered and the dielectric filter 1 is completed.

FIG. 3 is a plan view showing another embodiment of the resist showing the attachment position of the combined substrate 7. In this embodiment, when the spacer 8'has a dimension in the longitudinal direction and the width direction larger than that of the combined substrate 7, the mounting position of the combined substrate 7 is formed by a resist 11 ', and the combined substrate 7 on the surface of the spacer 8'is formed. The area other than the area 12 on which is mounted is covered with a resist 11 '. In contrast to FIG. 3, the rectangular area 12 on which the combined substrate 7 is placed may be covered with the resist 11 '. The combined substrate 7 is attached to the surface of the spacer 8 by aligning the four sides with the rectangular region 12 surrounded by the resist 11 '.

In the above embodiment, the marks indicating the mounting positions A and A'of the combined substrate 7 are formed by the edge portions of the resists 11 and 11 ', so that the mounting positions A and A'are indicated. If so, the shapes of the resists 11 and 11 'are not limited to those shown in FIGS.

By the way, in the above embodiment, the marks indicating the mounting positions A 1 and A ′ of the combined substrate 7 are formed by the resists 11 and 11 ′, but the combined substrate is formed by the connection electrodes D 4 and D 5 of the combined substrate 7. The marks at the mounting positions A and A'of 7 may be formed. For example, as shown in FIG. 4, convex connecting electrodes D4 'and D5' may be formed, and the mounting positions A and A'of the coupling substrate 7 may be indicated by the stepped portions of the electrode shapes.

Although the BPF has been described in the above embodiment, the present invention is applied to an arbitrary dielectric filter having a structure in which the coupling substrate is separated from the side surface of the case through a spacer having a larger area than the coupling substrate. can do.

[0019]

As described above, according to the present invention, a mark for indicating a mounting position of the coupling substrate is provided on a spacer for supporting the coupling substrate for connecting a plurality of dielectric coaxial resonators in a cascading manner apart from the case. Since the structure is formed, the displacement of the mounting position of the coupling substrate with respect to the spacer is reduced, and the variation in the filter characteristics is reduced. Further, the alignment on the spacer surface of the combined substrate becomes easy, and the work of assembling the dielectric filter becomes easy.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a structure of a dielectric filter according to the present invention.

FIG. 2 is a diagram in which a mounting position of a combined substrate on a spacer is formed with a resist.

FIG. 3 is a diagram showing another embodiment of a resist showing a mounting position of a combined substrate.

FIG. 4 is a diagram in which an attachment position of a combined substrate on a spacer is formed by electrodes.

FIG. 5 is a diagram showing a circuit configuration of a dielectric filter according to the present invention.

FIG. 6 is a main part perspective view showing the structure of a conventional dielectric filter.

[Explanation of symbols]

 1 Dielectric Filter 2, 3 Terminal 4 Dielectric 5 Hole 6 Conductive Member 7 Combined Substrate 8, 8'Spacer 9 Case 10 Cover 11, 11 'Resist 12 Area on which Combined Substrate is Placed A, A'Mounting Position C1 C4 capacitor D1 to D5 electrodes θ1 to θ3 dielectric coaxial resonator T1 to T3 coupling terminal

Claims (1)

[Scope of utility model registration request] 1. A dielectric filter in which a spacer made of a dielectric substrate is interposed between one surface of a case and a coupling board that cascade-connects a plurality of dielectric coaxial resonators, and a mounting position of the coupling board on the surface of the spacer. Is formed on the dielectric filter.