JP2002064302A - Dielectric filter and method for attaching dielectric resonator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dielectric filter capable of being miniaturized and holding a high Q value and a method for attaching this filter to a casing. SOLUTION: Radio waves inputted from an antenna 2a of a connector 2 are coupled by dielectric resonators 4 and 5 respectively held on holding stands 4' and 5' of a casing 1 and installed inclining resonance planes toward the opposed wall surfaces of the casing, and outputted from an antenna 3a through a connector 3. Since the degree of coupling is controlled by the angle of the inclination, there is no partition, the install interval of the resonators is made narrow while keeping the high Q value and the filter can be miniaturized. The dielectric resonator is attached onto a bottom surface 1c of the casing by adhesives filled in a space (not shown in Fig.).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter and a method for mounting a dielectric resonator.
The present invention relates to a dielectric filter provided with a dielectric resonator having an inclined resonance surface, and a method of attaching the dielectric resonator to the dielectric filter.

[0002]

2. Description of the Related Art In a mobile station radio apparatus which has been frequently used in recent years, various RF band and IF band filters are used as components of a transmitting / receiving circuit and an intermediate frequency circuit. Among them, the dielectric filter is highly used because of its low loss, relatively simple design, easy downsizing and weight reduction, and easy mass production. FIG. 4 is a diagram showing an example of a conventional dielectric band-pass filter. The overall configuration is such that input / output connectors 32 and 33 are attached to both end surfaces of a horizontally long rectangular casing 31, respectively. Coupling antennas 32 a and 33 a are connected to the inside of the housing 31 in communication with 33. Inside the housing 31 is a partition 3 with a window formed.
Housings 36, 37, and 38 are formed by 4, 35, and dielectric resonators 36a, 37a, and 38a are installed in the housings 36, 37, and 38, respectively, and the upper surface of the housing is closed by a lid (not shown). Configuration.

The above-mentioned dielectric resonators 36a, 37a, 38a
Of the dielectric resonators 36a, 37a, 38a with the bases 36b, 3
7b, 38b with an adhesive.
The portions 37b and 38b are fixed to the bottom surface of the housing 31 with an adhesive.

In the above configuration, the radio wave input to the input connector 32 is coupled from the coupling antenna 32a to the dielectric resonator (basic resonance TE01δ mode) 36a in the housing 36, and thereafter, the dielectric resonator in the housing 37 is sequentially arranged. Resonator 37a, dielectric resonator 3 in housing 38
8a, and coupled to the coupling antenna 33a to output from the output connector 33. At this time, radio waves in a frequency band defined by the dielectric resonators 36a, 37a, and 38a are output.

[0005]

The above prior art has the following problems. That is, 1) The pass frequency band (bandwidth) of the filter can be varied by the degree of coupling of the radio wave in the dielectric resonator.
In order to change the bandwidth, that is, to change the degree of coupling, the installation location of the partitions 34 and 35 is changed, or the partitions 34 and 35 are changed.
5 window width must be changed.
4 and 35 are formed as an integral structure with the housing 31, so they are determined at the design stage, and cannot be changed after the housing 31 is formed. 2) When trying to reduce the size of the filter, Partitions 34, 3
(5) The installation interval must be reduced, but if the installation interval is reduced, the Q value of the dielectric resonator decreases, the coupling loss increases, and the performance of the filter decreases. 3) To the housing of the dielectric resonator Is mounted with an adhesive, but because of poor adhesion, it cannot withstand shock and vibration, and the mounting position may be shifted or peeled off, especially in dielectric resonators with imbalanced weight distribution. The fear is strong.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a dielectric filter capable of miniaturizing while maintaining a high Q value and a dielectric filter having such a structure. An object of the present invention is to provide a method of mounting a dielectric resonator that is resistant to shock and vibration.

[0007]

According to a first aspect of the present invention, in a dielectric filter having a plurality of dielectric resonators in a housing, adjacent dielectric resonators are separated by a resonance surface. A dielectric filter is installed with a predetermined angle of inclination toward opposite wall surfaces of the housing.

According to a second aspect of the present invention, in the dielectric filter according to the first aspect, a radio wave coupling member is provided between adjacent dielectric resonators at a position facing the resonance surface of the housing wall. .

According to a third aspect of the present invention, in the dielectric filter according to the second aspect, the radio wave coupling member is a screw that can be continuously inserted into and removed from the housing.

According to a fourth aspect of the present invention, in the dielectric filter according to the first aspect, the radio wave coupling member is a screw that can be continuously inserted into and removed from the housing.

According to a fifth aspect of the present invention, a step of forming a recess in which a holding table for holding a dielectric resonator is inserted in a housing forming a dielectric filter, and the step of closing the holding table so as to cover the recess. Mechanically fixing the filter support member to be supported, filling the space defined by the bottom and peripheral edges of the concave portion and the filter support member with an adhesive after fixing the filter support member, The method of attaching a dielectric resonator includes a step of inserting a dielectric resonator into the dielectric resonator.

According to a sixth aspect of the present invention, in the method for mounting a dielectric resonator according to the fifth aspect, the step of mechanically fixing the filter support member is a step of fixing with a screw.

[0013]

FIG. 1 is a sectional view showing the structure of a dielectric filter to which the present invention is applied.
Are both end surfaces 1a, 1b of the horizontally long filter housing 1.
Are respectively connected to input / output connectors 2 and 3, and coupling antennas 2a and 3a are connected to the insides of the connectors 2 and 3, respectively. Bottom 1c of filter housing 1
, Dielectric resonators 4, 5 attached to holding tables 4 ′, 5 ′ are installed at predetermined intervals in the longitudinal direction of the filter housing 1, and the upper part of the filter housing 1 is covered with a lid 1. 'To block.

FIG. 2 is a sectional view taken along line AA of FIG. 1 and shows a mode in which dielectric resonators 4 and 5 are installed in the filter housing 1. In FIG. 2, a circular or square dielectric resonator 4 is
A cylindrical holder made of ceramics or alumina having a low dielectric constant and one end of which is obliquely cut.
Are bonded by an adhesive. Similarly, a circular or square dielectric resonator 5 is provided with an adhesive on a holding base 5 ′, which is a cylindrical holding base made of ceramics or alumina having a low dielectric constant and one end face of which is cut obliquely. Glued. Such dielectric resonators 4 and 5 are mounted so as to be inclined toward the mutually opposing wall surfaces 1 d and 1 e of the filter housing 1. At this time, the inclination angles θ of the dielectric resonators 4 and 5 with respect to the housing bottom surface 1c are respectively 0 <θ <45 °.
Set to be within the range. That is, the inclination angle is 0 degree or more (excluding 0 degree) and 45 degrees or less (excluding 45 degrees).
By setting the range, the coupling of radio waves is maintained, and the function as a filter is secured.

In this case, by appropriately adjusting and setting the inclination angle within the above-mentioned angle range, the degree of coupling of radio waves can be changed at intervals between adjacent dielectric resonators. You do not need to change the window width. Therefore, the Q value of the dielectric resonator does not decrease. Further, the interval between the dielectric resonators 4 and 5 can be reduced while adjusting the inclination angle. Therefore, the size of the filter can be reduced.

As described above, the degree of coupling of radio waves can be adjusted by physical means such as mounting the dielectric resonators 4 and 5 at different inclination angles.
(Or 1e) with the adjusting screw 6 provided in the dielectric resonators 4, 5
It is also possible by interposing it in and out. Therefore, even if the mounting is performed including the inclination angle θ of 0 degree or 45 degrees, radio waves can be coupled, so that the configuration of the dielectric resonator is facilitated. In addition, the inclination angle θ is
Since the angle is set to the angle c, the adjustment screw 6 can be formed by mounting a screw hole perpendicularly to the housing wall surface 1d, and adjustment can be performed with the strongest coupling. Therefore, the adjustment range of the coupling is widened, and the adjustment range of the inclination angle is substantially widened.

Next, a method of attaching the dielectric resonators 4 and 5 to the housing 1 will be described. Hereinafter, the dielectric resonator 4
Will be described, but the same applies to the dielectric resonator 5. FIG. 3 is a partially enlarged cross-sectional view of the bottom surface of the housing for explaining a method of attaching the dielectric resonator 4 to the bottom surface 1c of the housing 1. 4 with a diameter H2 larger than the diameter H1 of the holding table 4 ',
A circular recess 1f having a depth of, for example, about 1 mm is formed. The ring-shaped disk 7 is attached to the circular recess 1f by mechanical means such as screws 8, 8 '. The ring-shaped disk 7 has a circular cutout portion 7a having a diameter equal to the diameter H1 of the holder 4 'of the dielectric resonator 4 at the center of the disk, and a screw 8 around the disk.
It has an 8 'screw hole. Although only two screws are shown in FIG. 3 for the cross-sectional view, an appropriate number of screws may be provided around the disk.

In such a configuration, the dielectric resonator 4
Is attached to the filter housing bottom surface 1f, first, the ring-shaped disc 7 is put on the circular concave portion 1f, and is fixed to the housing bottom surface 1c with screws 8, 8 '. Next, the space 9 formed by the ring-shaped disk 7 and the circular recess 1f is filled with an epoxy resin-based adhesive (for example, Araldite (trade name) manufactured by Nagase Ciba Co., Ltd.). The dielectric resonator 4 is mounted by applying the coating to 1 f and inserting the holding table 4 ′ therein.

Usually, an adhesive has a strong adhesive performance to a single material, but it is required to have a strong adhesive performance of the same strength to a plurality of materials, for example, a metal and a ceramic. Is in a difficult situation. Further, since the inside of the housing is in a mirror-finished state by silver plating, the adhesive is more difficult to adjust to. In such a situation, according to the mounting method of the present embodiment, the adhesive is applied to the back surface of the ring-shaped disk 7, the peripheral portion of the circular concave portion 1f, and the space portion 9 also formed of three surfaces of the bottom surface. Is locked in
This prevents the adhesive from peeling off the metal surface. The adhesive keeps a strong adhesive force with the ceramic holder 4 ′, so that the dielectric resonator 4 can be firmly attached to the housing 1. In particular, in a dielectric filter having a dielectric resonator whose weight distribution is unbalanced, such as the dielectric resonator 4 attached to the cylindrical holding base 4 ′ having an inclined end surface, Even when attached to equipment and used, it can withstand external shocks and vibrations.

Incidentally, there is no conventional ring-shaped circular plate, and in the mounting method in which an adhesive is simply applied to a circular recess and a dielectric resonator is inserted, for example, the dielectric resonator in a dielectric filter used in the 800 MHz band is used. Has a diameter of 55 mm, a thickness of 32 mm, and a weight of about 500 g, and it was difficult to mount it so as to withstand rolling vibration or impact. Strong attachment is possible without worrying about adhesiveness.

[0021]

According to the first aspect of the present invention, adjacent dielectric resonators are installed such that the resonance surface of each dielectric resonator has a predetermined inclination angle toward the opposite wall surface of the housing. Therefore, even if the distance between the adjacent dielectric resonators is reduced, the coupling state of the radio waves can be maintained by the inclination angle, so that the size of the dielectric filter can be reduced. At this time, since there is no need to provide a partition, the Q
The value does not decrease.

According to the second aspect of the present invention, since the coupling state of the radio waves between the resonators can be adjusted by the radio wave coupling member, substantially the same effect as adjusting the inclination angle of the dielectric resonator can be obtained. can get. Moreover, in this case, the inclination angle θ
Can maintain the coupling state even when the angle is 45 degrees at which the coupling is not maintained, so that the configuration of the filter is facilitated.

Advantageous Effect Corresponding to Claim 3: In addition to the effect corresponding to Claim 2, since the coupling state of radio waves between the resonators can be continuously adjusted, the inclination angle of the dielectric resonator can be continuously adjusted. The same effect can be obtained as if it were adjusted dynamically. Since the radio wave coupling member can be vertically mounted on the housing wall surface, the mounting process is facilitated.

According to the fourth aspect: A dielectric filter can be easily formed.

Advantageous Effects According to Claims 5 and 6: The adhesive for mounting the dielectric resonator is used while paying attention only to the material of the holder of the resonator without being restricted by the adhesiveness to the material of the housing. become able to. Therefore, even if the adhesiveness to the housing part is weak, it is possible to mount firmly, and even in the case of a dielectric resonator whose weight distribution is unbalanced, it is possible to mount strongly against external shock and vibration. Also, the mounting can be performed in a simple process.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram of a dielectric filter to which the present invention is applied.

FIG. 2 is a diagram showing a state where the dielectric resonator of the present invention is installed in a housing.

FIG. 3 is a partially enlarged sectional view of a housing bottom for explaining a method of mounting the dielectric resonator of the present invention.

FIG. 4 is a diagram showing an example of a conventional dielectric filter.

[Explanation of symbols]

1. Filter housing, 2. Input connector, 3. Output connector, 4. Dielectric resonator, 4 '... Holder, 5.
.Dielectric resonator, 5 '.. holding stand, 6..adjustment screw, 9
..Space parts

Claims (6)

[Claims] In a dielectric filter having a plurality of dielectric resonators in a housing, adjacent dielectric resonators are positioned such that the resonance surfaces of the respective dielectric resonators face opposite wall surfaces of the housing. A dielectric filter, wherein the dielectric filter is installed with an inclination angle of. 2. The dielectric filter according to claim 1, wherein a radio wave coupling member is provided between the adjacent dielectric resonators at a position facing the resonance surface of the housing wall. 3. The screw according to claim 2, wherein the radio wave coupling member is a screw that can be continuously inserted into and removed from the housing.
The dielectric filter as described in the above. 4. The dielectric filter according to claim 1, wherein the dielectric resonator is a circular or square dielectric resonator, and is held by a holding table having an inclined end surface. 5. A step of forming a recess in which a holder for holding a dielectric resonator is inserted in a housing forming a dielectric filter, and a filter support member for supporting the holder so as to cover the recess. Mechanically fixing the filter, fixing the filter support member, filling the space defined by the bottom and periphery of the concave portion and the filter support member with an adhesive, and filling the concave portion with a dielectric resonator. A method for mounting a dielectric resonator, comprising a step of inserting a dielectric resonator. 6. The method according to claim 5, wherein the step of mechanically fixing the filter support member is a step of fixing with a screw.