GB2273002A

GB2273002A - Dielectric resonator

Info

Publication number: GB2273002A
Application number: GB9324238A
Authority: GB
Inventors: Kuniaki Kiyosue; Toshiharu Noguchi; Tadanobu Uchiyama; Takehiko Yoneda
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 1992-11-27
Filing date: 1993-11-25
Publication date: 1994-06-01
Anticipated expiration: 2013-11-25
Also published as: JP3068719B2; GB2273002B; JPH06164218A; GB9324238D0

Abstract

The resonant frequency of a dielectric resonator comprising, on the surface of a dielectric substrate (7), an outer conductor (8), an inner conductor (9) and a short-circuiting conductor (10. Fig. 2 not shown) is adjusted by removing part of the outer conductor (8) to form an aperture (11). If the resonance frequency is higher than a target resonance frequency as a result of forming the aperture (11), the resonance frequency is then reduced by putting a member (12) of a conductive paste or a high dielectric constant paste or the like in the aperture (11). <IMAGE>

Description

Dielectric resonator The present invention relates to a dielectric resonator which is for use, for instance,in telecommunication apparatuses and a method for adjusting the resonance frequency of such dielectric resonator.

FIG.6 is a perspective view of a conventional dielectric resonator viewed from its open end face side, FIG.7 is a perspective view of said resonator viewed from its short-circuited end face and FIG.8 is a crosssectional view of said dielectric resonator, respectively.

In these figures, a dielectric substrate 1 made of a dielectric material is configured to have a tubular shape comprising an exterior side face, an interior side face 100, an open end face la and a short-circuited end face lb. On the exterior side face of the dielectric substrate 1, there is formed an outer conductor 2, and on the interior side face of the dielectric substrate 1, there is formed an inner conductor 3. On the shortcircuited end face ib, which is another end face of the dielectric substrate, there is formed a short-circuiting conductor 4 which connects the outer conductor 2 with the inner conductor 3. A first cut-out part (hereinafter, to be referred to as cutting) 5 is formed on the outer conductor 2 by obliquely cutting the outer conductor 2 together with a part of the dielectric substrate 1 at its side of the open-ended face la.Further, a second cutout part (hereinafter, to be referred to as slot) 6 is formed on the short-circuiting conductor 4 by cutting a part of the conductor 4 together with a part of the dielectric substrate 1.

A conventional method for adjusting the resonance frequency of the conventional dielectric resonator configured as mentioned above will now be described.

First, a dielectric resonator, whose resonance frequency has not yet been adjusted, namely, the cutting 5 and the slot 6 have not been formed, is prepared. The dielectric resonator before the resonance frequency adjustment is configured in a manner that it has a resonance frequency which is slightly lower than a desired resonance frequency. Thereafter, the dielectric resonator is machined to have the desired resonance frequency by removing a part of the outer conductor 2 at its side to the open end face la by means of a cutting machining tool such as a rotational grinding stone. In this machining process, the cutting 5 is formed. The larger is made the size of the cutting 5 (namely, the larger is the amount of the outer conductor 2 to be removed), the higher the resonance frequency of the machined dielectric resonator becomes.

If the dielectric resonator has the desired resonance frequency as it is produced, there is no need to provide the cutting 5. In most cases, however, the dielectric resonators before adjustment of the resonance frequency does not always have the desired accurate resonance frequencies. In the actual manufacturing process, deviations from the intended values are hardly avoidable in the film thickness of the outer conductor 2 and the inner conductor 3 as well as in the dimension of the dielectric substrate 1.

Therefore, it is a general practice to previously manufacture such a dielectric resonator which has a resonance frequency which is slightly lower than the intended or desired value, and then to finish the dielectric resonator to adjust the resonance frequency to the desired value. The conventional adjustment has been made by removing the parts of the outer conductors 2 at its side near the open end face la so as to form a cutting 5, as shown in FIG.6 and FIG.7, thereby making the resonance frequency higher.

However, when the cutting 5 is once provided to be too large, the resonance frequency would become higher than the desired value. In that case, an inverse adjustment should be performed by forming a slot 6 thus removing a part of the short-circuiting conductor 4 hence decreasing the resonance frequency. As a result of this adjustment, the slot 6 is provided on the short-circuiting conductor 4. The larger is the size of the slot 6, the lower the resonance frequency becomes. By repeating the above-mentioned adjustment processes, the resonance frequency of the dielectric resonator is finally adjusted accurately to the target value.

As previously described, in the conventional dielectric resonators, when the resonance frequency is made higher than the target value by excessively cutting the outer conductor 2 in forming the cutting 5, the resonance frequency must then be adjusted to the target value by further extending the slot 6 thereby decreasing the resonance frequency. Covered area by the conductors (the outer conductor 2 and the short-circuiting conductor 4) provided on the exterior surfaces of the dielectric substrate 1, however, decreases by providing the slot 6, and hence Q value of the dielectric resonator is lowered.

As a result, there is a problem that a pass band insertion loss of a filtering apparatus is deteriorated in a filtering apparatus configured by incorporating such a resonator. Further, by providing the slot 6 and thus exposing a part of the short-circuited end face ib of the dielectric substrate 1, an electromagnetic shielding performance of the dielectric resonator is also deteriorated. Thereby, undesirable leakage of an electromagnetic wave from the dielectric resonator increases. As a result, there is another problem that the leakage of electromagnetic wave may adversely influence other electronic components, circuits and so on, and sometimes may cause generation of noises in the telecommunication apparatus and etc.

The present invention proposes to solve the above-mentioned problems, and has, as its object, a provision of a dielectric resonator that does not deteriorate the pass band insertion loss of the filtering apparatus which incorporates the dielectric resonator therein and can prevent the generation of the noise in the telecommunication apparatus using it. The present invention further purposes to provide a method for adjusting the resonance frequency of the same.

According to the present invention, there is provided a dielectric resonator comprising, a dielectric substrate made of a dielectric substance, having an interior side face, an exterior side face, an open end face and a short-circuited end face, an inner conductor provided on said interior side face of said dielectric substrate, an outer conductor provided on said exterior side face of said dielectric substrate, a short-circuiting conductor provided on said short-circuited end face for connecting said inner conductor to said outer conductor, at least one cutting provided on said outer conductor at the side of the open end face, and at least one attachment member provided on said cutting.

In the above-described dielectric resonator, said attachment member is preferably an electricallyconductive member which may be a cured product of an epoxy resin conductive paste. The epoxy resin conductive paste may contain silver. The electrically-conductive member may alternatively be a metal strip. The attachment member may not necessarily be provided in contact with the outer conductor, but it may be formed in a manner that it does not in contact with the outer conductor.

In the above-described dielectric resonator, said attachment member may alternatively be formed with a dielectric substance having a dielectric constant preferably larger than that of the dielectric substrate.

According to another aspect of the present invention, there is provided in the method for adjusting the resonance frequency of the previously disclosed dielectric resonator before the formation of the cutting and the provision of the attachment member; a method for adjusting the resonance frequency of the dielectric resonator comprising, forming at least one cutting on said outer conductor at the side of the open end face, thereby adjusting the resonance frequency to a given value, and in the event that the resonance frequency is made higher than the given value by forming said cutting, providing an attachment member on said cutting, thereby decreasing the resonance frequency to cause the resonance frequency to approach the given value.

According to a further aspect of the present invention, the method for adjusting the resonance frequency of the previously disclosed dielectric resonator with the cutting comprises, providing at least one attachment member on said cutting, for causing the resonance frequency to approach a given value.

In the event that the resonance frequency is made lower than the given value again after the provision of the attachment member on the cutting by the abovementioned method, a part of said attachment member may be removed, thereby to increases the resonance frequency to a given value.

According to a still further aspect of the present invention, the method for adjusting the resonance frequency of the above-mentioned dielectric resonator comprises: a step of measuring the resonance frequency of said dielectric resonator, a step of forming at least one cutting on the outer conductor at the side of the open end face of the dielectric resonator which does not have a given resonance frequency, for adjusting its resonance frequency, a step of measuring the resonance frequency of the dielectric resonator whose resonance frequency is adjusted by forming said cutting, and a step of adjusting the resonance frequency of the dielectric resonator which has been found not to have the given resonance frequency in the previous step, by providing at least one attachment member on the cutting.

According to the present invention, it is possible to decrease the resonance frequency and to obtain the resonance frequency of a target value by providing the attachment member on the cutting formed on the outer conductor near the open end face, without resorting to the provision of a cut-out part on the short-circuiting conductor. Therefore, it is possible to effectively prevent the deterioration in the pass band insertion loss and to suppress the generation of the noises in the telecommunication apparatuses incorporating the dielectric resonator.

While the novel features of the present invention are set forth particularly in the appended claims, the invention, both as to organization and content, will be better understood and appreciated, along with other objects and features thereof, from the following detailed description taken in conjunction with the attached drawings.

FIG.1 is a perspective view of a dielectric resonator built in accordance with a first embodiment of the present invention, viewed from its open-ended face side.

FIG.2 is a perspective view of the dielectric resonator shown in FIG.1, viewed from its short-circuited face side.

FIG.3 is a cross-sectional side view of the dielectric resonator shown in FIG.1.

FIG.4 is a perspective view of a dielectric resonator built in accordance with a second embodiment of the present invention, viewed from its open-ended face side.

FIG.5 is a perspective view of a dielectric resonator built in accordance with a third embodiment of the present invention, viewed from its open-ended face side.

FIG.6 is a perspective view of a conventional dielectric resonator, viewed from its open-ended face side.

FIG.7 is a perspective view of the dielectric resonator shown in FIG.6, viewed from its short-circuited face side.

FIG.8 is a cross-sectional view side of the dielectric resonator shown in FIG.6.

First Embodiment FIG.1, FIG.2 and FIG.3 show a dielectric resonator built in accordance with the first embodiment of the present invention. FIG.1 is a perspective view of the dielectric resonator viewed from its open-ended face side, FIG.2 is another perspective view of the dielectric resonator viewed from its short-circuited end face side, and FIG.3 is a cross-sectional side view of the dielectric resonator, respectively. In these figures, a tubular dielectric substrate 7 is made of a ceramic dielectric substance, such as BaO-TiO2, ZrO2-SnO2-TiO2, BaO-Nd203 Tit2, and BaO-Sm203-TiO2.

On an exterior side face of the dielectric substrate 7, there is formed an outer conductor 8, and on an interior side face of the dielectric substrate 7, there is formed an inner conductor 9. On a short-circuited end face 7b, which is the other end face of the dielectric substrate 7, there is formed a short-circuiting conductor 10 which electrically connects the outer conductor 8 with the inner conductor 9.

Each of the outer conductor 8, the inner conductor 9 and the short-circuiting conductor 10 is configured with a single layer of a metal film, or by laminating a plurality of metal films. In case of configuring these conductors (the outer conductor 8, the inner conductor 9 and the short-circuiting conductor 10) by laminating the plurality of the metal films, a copper layer of 2 - 4 um thickness is first formed on the entire surface of the dielectric substrate 7 except its open end side face, by means of non-electrolytic plating or the like process. Then, a solder film of 10 - 15 um thickness is laminated on the previously formed copper film by means of solder-dip plating to form a double layer.In an alternative case of forming the single metal film, a silver layer with a film thickness of 20 - 40 um is formed on the surface of the dielectric substrate 7 by painting a silver paste thereon. The conductor may be configured as the double layer of the laminated metal films, or as the single layer of the metal film. The conductors may alternatively be formed in a triple or more multiple layer. Further, although solder, copper and silver are exemplified as the material for the metal films, any other electrically-conductive substance may alternatively be employed.

A cutting 11 is provided in a manner that a part of the outer conductor 8 is cut out or peeled off the surface of the dielectric substrate 7 at its side to the open end face 7a, and is filled with an attachment member 12. In this embodiment, although the cutting 11 is formed by means of a cutting machine tool and thus a part of the dielectric substrate 7 is also removed together with the outer conductor 8, the removal of only a specified part of the outer conductor 8 is required. The cutting 11 may therefore be formed by any other means such as etching process without resorting to the machine tool cutting.

Thereby only the specified part of the outer conductor 8 is removed.

Although the attachment member 12 in this embodiment is provided in a manner that an outer plane formed by the attachment member 12 is even with an outer plane of the- outer conductor 8, the outer plane of the conductive attachment member 12 may be projected from that of the outer conductor 8, or may be depressed from the latter. Moreover, the conductive attachment member 12 may be provided on the cutting 11 in a manner not in contact with the outer conductor 8. Although the conductive attachment member 12 in this embodiment is provided confined only within the cutting 11, the attachment member 12 may alternatively be swollen out in an exposed part of the open end face 7a of the dielectric substrate 7 or over a part of the outer conductor 8 without bringing any adverse influence on the performance or characteristics of the dielectric resonator.

As a material for the attachment member 12, an electrically-conductive paste containing an epoxy resin and the like is suitable. Namely, the epoxy resin conductive paste is first painted on the cutting 11 and then is converted into the conductive attachment member 12 by curing the painted layer of the epoxy resin conductive paste in a thermal treatment. It is preferable to use such an epoxy resin conductive paste having viscosity of 300 poise or more measured under the conditions of 0.5 rpm. at 25 "C, and a thixotropy of 2 - 2.5 or more.

Further, as a metal for dispersing in the epoxy resin conductive paste, silver is usually used. In case of using silver as the dispersed metal, it is desirable to make the epoxy resin conductive paste contain the silver of 70 % by weight or more. An epoxy resin conductive paste containing silver at 50 % by weight or less is not preferable because it deteriorates the Q value of the dielectric resonator. It is preferable to use such an epoxy resin conductive paste that has a good durability after it is cured. That is, after being subjected to a dip soldering in an assembling process, a finished product of the dielectric resonator is usually washed in a supersonic washer with a solvent and stood there for a few minutes, and then dried.Therefore, the epoxy resin conductive paste should be selected in a manner that the cured resin has such a durability as to not dissolve in the solvent or be peeled off the surface of the dielectric substrate in the above-mentioned washing treatment.

Further, it is preferable to select the epoxy resin conductive paste in a manner not to have a curing temperature under 183 "C, which is an azeotropic temperature of the solder. If the curing temperature is no lower than 183 "C, the curing would be a cause for the malfunction of the apparatus which incorporates the dielectric resonator because the solder is employed for joining the dielectric resonator with other components in the apparatus. In addition, the curing time of one hour or less is preferable from the point of view of possible thermal damages to other components.

As a material for the conductive attachment member 12, an alloy such as solder may also be used. In that case, a molten alloy such as solder is filled in the space formed by the cutting 11 and is hardened therein by cooling it down to a room temperature, to form the conductive attachment member 12.

Alternatively, a metal strip may be glued to the cutting 11 as the conductive attachment member 12.

Namely, a metal foil of copper, silver, solder or the like may be glued to the cutting 11 with an organic adhesive agent.

The dielectric resonator configured as described above does not need a slot in its short-circuiting conductor 10 as provided in the conventional ones, as specifically shown in FIG.7, and hence, it does not leak the electromagnetic wave outside of the dielectric resonator. Further, in the dielectric resonator, a high Q value is assured, because the adjustment of the resonance frequency can be made by removing only a small amount of the outer conductor on the exterior side face of the dielectric resonator.

Second Embodiment FIG.4 is a perspective view similar to that of FIG.1 of a dielectric resonator built in accordance a second embodiment. In the second embodiment, the components other than a conductive attachment member 14 are identical with those in the first embodiment and the description therefor will be omitted. The conductive attachment member 14 is provided on the cutting 11 in a manner not to contact the outer conductor 8. Namely, the conductive attachment member 14 is located in the space formed by the cutting 11 as an island, forming a groove of a certain width with the outer conductor 8 which surrounds the island. In this embodiment, a fine adjustment of the resonance frequency of the dielectric resonator can be performed by varying the width of the groove.

Third Embodiment FIG.5 is a perspective view of a dielectric resonator built in accordance a third embodiment similar to that of FIG.1. In the third embodiment, the components other than a conductive attachment member 13 are identical with those in the first embodiment and the description therefor will be omitted. The attachment member 13 is however a component configured with a dielectric substance and is glued to the cutting 11. In forming the attachment member 13, a resin paste containing a dielectric substance may be painted on the cutting 11 and then cured therein.

It is preferable to use such a dielectric substance which has a larger dielectric constant than that of the dielectric substrate 7, and it is effective for decreasing the resonance frequency of the dielectric resonator.

Adjustment Process I In the following paragraphs, a method for adjusting the resonance frequency of the dielectric resonator of the above-mentioned embodiments is elucidated with reference to FIG.1 through FIG.3.

First, after manufacturing the dielectric substrate 7, a metal film is formed on the entire surface of the dielectric substrate 7 by non-electrolytic plating or the like method and an open end face 7a is formed on one end face of the dielectric substrate 7 by subjecting it to a grinding or the like process. The half-finished dielectric resonator has been manufactured in a manner that it has a slightly lower resonance frequency than a target resonance frequency. Next, a part of the outer conductor 8 at the side of the open end face 7a is removed to form the cutting 11 by means of machine tool cutting or the like process, thus to adjust the dielectric resonator to the given resonance- frequency. The larger is the amount of the outer conductor 8 to be removed (the wider is the area of the cutting 11), the higher the resonance frequency becomes. If the target resonance frequency is acquired, the adjustment of the resonance frequency is completed. On the contrary, if the cutting 11 is formed too large, the resonance frequency becomes higher than the target value. In this adjustment process, the resonance frequency is by providing the attachment member 12 on the cutting 11, instead of the conventional cutting out of the slot on the short-circuiting conductor.

Since the amount of the conductor removed for the adjustment is small in this embodiment the deterioration of the Q value is small and the leakage of the electromagnetic wave is small, and therefore, it is possible to effectively suppress the generation of the noises from the apparatus which incorporates the dielectric resonator. In attaching the attachment member 12 on the cutting 11, the wider is the area covered by the attachment member 12, the lower the resonance frequency becomes. When the target resonance frequency is reached in this step, the adjustment of the resonance frequency is completed. However, if the attachment member 12 would be attached too wide in the cutting 11 in this step hence excessively lowering the resonance frequency, the resonance frequency is raised again toward the target resonance frequency by removing a part of the attachment member 12.In this manner, the step of attaching the attachment member 12 on the cutting 11 and the other step of removing the part of the attachment member are alternately repeated till finally reaching the target resonance frequency.

According to the above-described process for adjusting the resonance frequency of the dielectric resonator, a part of the short-circuiting conductor 10 is not removed as in the conventional ones, but the attachment member 12 is provided on the cutting 11.

Therefore, it is possible to adjust the resonance frequency of the dielectric resonator without deteriorating the performance or characteristics (the pass band insertion loss and the like) of the finished resonator.

Adjustment Process II In the following paragraphs, another method for adjusting the resonance frequency will be described with reference to FIG.1 through FIG.5.

In this process also, after manufacturing the dielectric substrate 7, a metal film is formed on the entire surface of the dielectric substrate 7 by the similar method to the previous adjusting method, and an open end face 7a is formed on one end face of the dielectric substrate 7 by subjecting it to a grinding or the like process. At the time of forming the open end face 7a, the resonance frequencies of the half-finished dielectric resonators are measured, and the dielectric resonators are classified into a first group of ones already having the target resonance frequency (a first group) and another group of ones having resonance frequencies different from the target resonance frequency (a second group). The dielectric resonators belonging to the first group are assumed as the finished products.The resonance frequencies of the resonators belonging to the second group are not at the accurate target resonance frequency. Therefore, a part of the outer conductor 8 at the side of the open end face 7a of each of the resonators is removed to form the cutting 11 by means of machine tool cutting and the like process, thereby to make the dielectric resonator have the given resonance frequency.

The larger is the amount of the outer conductor 8 to be removed (the wider is the area of the cutting 11), the higher the resonance frequency becomes. If the target resonance frequency is reached, the adjustment of the resonance frequency is completed. But, if the cutting 11 is formed too large, the resonance frequency becomes higher than the given one. Although the resonance frequency can be decreased by providing another cut-out part (slot) on the short-circuiting conductor 10 as in the case of the conventional one, in this adjustment process however, the resonance frequency is alternatively decreased by providing the attachment member 12 on the cutting 11.

Since the amount of the conductor removed for the adjustment is small in this embodiment, the deterioration of the Q value is also small and the leakage of the electromagnetic wave is small, and hence, it is possible to effectively suppress the generation of the noises in the apparatus which incorporates the dielectric resonator. In attaching the attachment member 12 on the cutting 11, the wider is the area covered by the attachment member 12, the lower the resonance frequency becomes. When the given resonance frequency is reached in this process, the adjustment of the resonance frequency is completed. However, if the attachment member 12 is attached too wide area of the cutting 11 in this step, and the resonance frequency becomes too low, the resonance frequency is increased again to a given resonance frequency by removing a part of the attachment member 12.

In this manner, the steps of attaching the attachment member 12 on the cutting 11 and the steps of removing the part of the attachment member are repetitively performed.

And, the measurements of the resonance frequency are performed after the every adjustment steps, for finally reaching the target resonance frequency.

Adjustment Process III In the case of a dielectric resonator built in accordance with the second embodiment shown in FIG.4, wherein the conductive attachment member 14 locates in the space formed by the cutting 11 as an island, forming a gap or groove of a certain width with the outer conductor 8 which surrounds the island, the fine adjustment of the resonance frequency of the dielectric resonator is performed in a manner similar to those of the foregoing adjustment processes, with the exception of varying the width of the gap or groove, instead of varying the area covered by the attachment member. The narrower is the width of the groove, the lower the resonance frequency becomes.

Adjustment Process IV In the case of a dielectric resonator built in accordance with the third embodiment shown in FIG.5, wherein the attachment member 13 is configured with a dielectric substance and is glued to the cutting 11, the adjustment of the resonance frequency of the dielectric resonator is performed in a manner similar to the foregoing adjustment processes, except for varying the amount of the dielectric substance or the attachment member. The larger is the amount of the dielectric substance or the attachment member 13, the lower the resonance frequency becomes.

As above-described, this adjustment process is characterized by the provision of a step for previously checking the resonance frequency of the half-finished dielectric resonators and for classifying them into the groups by their resonance frequency, prior to actual adjustment working.

Although the present invention has been described in terms of the presently preferred embodiments, it is to be understood that such disclosure is not to be interpreted as limiting. Various alterations and modifications will no doubt become apparent to those skilled in the art to which the present invention pertains, after having read the above disclosure.

Claims

1. A dielectric resonator comprising: a dielectric substrate having interior and exterior side faces and first and second end faces, an inner conductor provided on said interior side face of said dielectric substrate, an outer conductor provided on said exterior side face of said dielectric substrate, a short-circuiting conductor provided on said second end face and connecting said inner conductor to said outer conductor, an aperture in said outer conductor and at the side of said first end face, and a resonance-adjustment member provided in said aperture.

2. The dielectric resonator in accordance with claim 1, wherein said resonance-adjustment member is an electrically-conductive member.

3. The dielectric resonator in accordance with claim 2, wherein said electrically-conductive member is a cured product of an epoxy resin conductive paste.

4. The dielectric resonator in accordance with claim 3, wherein said epoxy resin conductive paste contains silver.

5. The dielectric resonator in accordance with claim 2, wherein said electrically-conductive member is a metal strip.

6. The dielectric resonator in accordance with claim 1, wherein said resonance-adjustment member does not contact said outer conductor.

7. The dielectric resonator in accordance with claim 1, wherein said resonance-adjustment member comprises a dielectric substance whose dielectric constant is larger than that of said dielectric substrate.

8. A method for adjusting the resonance frequency of a dielectric resonator comprising a dielectric substrate having interior and exterior side faces and first and second end faces, an inner conductor provided on said interior side face of said dielectric substrate, an outer conductor provided on said exterior side face of said dielectric substrate, and a short-circuiting conductor provided on said second end face and connecting said inner conductor to said outer conductor, the method comprising:: forming an aperture in said outer conductor and at the side of said first end face, thereby increasing the resonance frequency towards a desired value; and, in the event that the resonance frequency is increased above said desired value by forming said aperture, providing a resonance-adjustment member in said aperture, thereby decreasing the resonance frequency to cause the resonance frequency to approach said desired value.

9. The method in accordance with claim 8, further comprising, in the event that the resonance frequency is decreased below said desired value by providing said resonanceadjustment member in said aperture, removing a part of said resonance-adjustment member, thereby increasing the resonance frequency to cause the resonance frequency to approach said desired value.

10. The method in accordance with claim 8 or 9, wherein said resonance-adjustment member is an electrically-conductive member.

11. The method in accordance with claim 10, wherein said electrically-conductive member is formed from an epoxy resin conductive paste.

12. The method in accordance with claim 11, wherein said epoxy resin conductive paste contains silver.

13. The method in accordance with claim 10, wherein said electrically-conductive member is a metal strip.

14. The method in accordance with claim 8, wherein said resonance-adjustment member does not contact said outer conductor.

15. The method in accordance with claim 8, wherein said resonance-adjustment member comprises a dielectric substance whose dielectric constant is larger than that of said dielectric substrate.

16. A method for adjusting the resonance frequency of a dielectric resonator comprising a dielectric substrate having interior and exterior side faces and first and second end faces, an inner conductor provided on said interior side face of said dielectric substrate, an outer conductor provided on said exterior side face of said dielectric substrate, a short-circuiting conductor provided on said second end face and connecting said inner conductor to said outer conductor, and an aperture in said outer conductor and at the side of said first end face, the method comprising: providing a resonance-adjustment member in said aperture, thereby causing the resonance frequency to approach a desired value.

17. The method in accordance with claim 16, further comprising, in the event that the resonance frequency is decreased below said desired value by providing said resonanceadjustment member in said aperture, removing a part of said resonance-adjustment member, thereby increasing the resonance frequency to cause the resonance frequency to approach said desired value.

18. The method in accordance with claim 16 or 17, wherein said resonance-adjustment member is an electrically-conductive member.

19. The method in accordance with claim 18, wherein said electrically-conductive member is formed from an epoxy resin conductive paste.

20. The method in accordance with claim 19, wherein said epoxy resin conductive paste contains silver.

21. The method in accordance with claim 18, wherein said electrically-conductive member is a metal strip.

22. The method in accordance with claim 16, wherein said resonance-adjustment member does not contact said outer conductor.

23. The method in accordance with claim 16, wherein said resonance-adjustment member comprises a dielectric substance whose dielectric constant is larger than that of said dielectric substrate.

24. A method for adjusting the resonance frequency of a dielectric resonator comprising a dielectric substrate having interior and exterior side faces and first and second end faces, an inner conductor provided on said interior side face of said dielectric substrate, an outer conductor provided on said exterior side face of said dielectric substrate, and a short-circuiting conductor provided on said second end face and connecting said inner conductor to said outer conductor, the method comprising the steps of: (i) measuring the resonance frequency of said dielectric resonator; (ii) if said dielectric resonator does not have a desired resonance frequency, forming an aperture in said outer conductor and at the side of said first end face, thereby adjusting the resonance frequency of said dielectric resonator; (iii) measuring the resonance frequency of said dielectric resonator; and (iv) if said dielectric resonator does not have said desired resonance frequency, adjusting the resonance frequency of said dielectric resonator by providing a resonance-adjustment member in said aperture.

25. A dielectric resonator substantially as herein described with reference to, or with reference to and as illustrated in, Figures 1 to 3, Figure 4 or Figure 5.

26. A method for adjusting the resonance frequency of a dielectric resonator, substantially as herein described with reference to Figures 1 to 3, Figure 4 or Figure 5.