JP4871930B2 - Multimode dielectric resonator and adjustment method thereof - Google Patents

Description

  The present invention relates to a multimode dielectric resonator capable of exciting a plurality of resonance modes corresponding to a plurality of frequencies.

In general, a base station such as a mobile phone incorporates a resonator filter. In order to configure such a resonator filter with a small size and high performance, a multimode resonator capable of responding to a plurality of frequencies by exciting a plurality of resonance modes has attracted attention. As such a multimode resonator, various structures such as a structure using a cylinder or a structure using a rectangular parallelepiped have been proposed (for example, see Patent Documents 1 and 2). In order to excite a plurality of resonance modes in a structure using a rectangular parallelepiped shape, it is necessary to adopt a structure in which a plurality of rectangular parallelepipeds are combined or a structure in which a part of the rectangular parallelepiped is three-dimensionally deleted. In addition, in order to excite a plurality of resonance modes in a structure using a cylindrical shape, it is necessary to employ a structure provided with a screw member, a cylindrical hole or the like for adjusting the characteristics of the resonator body.
JP-A-57-194603 JP-A-61-121502

  However, a structure using a rectangular parallelepiped shape among the above-described multimode resonators needs to have a complicated shape in order to adjust a desired filter characteristic at the time of manufacturing, leading to an increase in manufacturing cost. On the other hand, among the above-described multimode resonators, a structure using a cylindrical structure has a relatively simple resonator body and is easy to manufacture. However, if it is assumed that the structure for adjusting the characteristics is provided, there are problems such as an increase in transmission signal loss due to the screw member and complicated processing for forming a cylindrical hole. Furthermore, if the frequency adjustment of the multi-mode resonator is performed using the above-described characteristic adjustment structure, a plurality of frequencies change in a complicated manner depending on the design conditions. It is not easy to realize the filter characteristics.

  Accordingly, the present invention has been made to solve these problems, and an object of the present invention is to provide a multimode dielectric resonator having a relatively simple structure, low transmission loss, and easy adjustment of desired characteristics. And

In order to solve the above-described problems, a multimode dielectric resonator according to the present invention is fixed in a cavity surrounded by a conductor, and a columnar dielectric resonator main body that excites a plurality of resonance modes, and the dielectric A dielectric adjustment piece disposed opposite to the upper surface or the bottom surface of the resonator body and configured to be adjustable in distance from the dielectric resonator body, the dielectric resonator body including a first frequency and the dielectric resonator piece. The resonance mode having a second frequency higher than the first frequency is excited, and the first frequency and the second frequency are changed by adjustment of the dielectric adjustment piece .

  According to the multimode dielectric resonator of the present invention, the columnar dielectric resonator main body excites a plurality of resonance modes, and corresponding frequency characteristics are imparted to the transmission signal. Then, by adjusting the distance from the dielectric resonator body by displacing the dielectric adjustment piece, it is possible to set the optimum frequency characteristic. Therefore, it is not necessary to provide a special structure such as a screw member or a cylindrical hole for adjusting the frequency characteristics, and a multimode dielectric resonator capable of easily adjusting a plurality of frequencies without complicated processing is realized. Can do.

  In the present invention, a part of the dielectric resonator main body may be cut to excite the plurality of resonance modes so that the frequency characteristic has an attenuation pole. As a result, it is possible to easily realize frequency characteristics corresponding to a plurality of resonance modes corresponding to the positional relationship between the cutting surface of the dielectric resonator body, the input terminal, and the output terminal.

  In the present invention, an input terminal and an output terminal are attached to the conductor on the side surface side of the dielectric resonator body, and the input terminal and the output terminal are respectively connected from a central axis within a circular cross section of the dielectric resonator body. May be orthogonal to each other, and the normal of the cut surface of the dielectric resonator body may form an angle of approximately 45 degrees with respect to the two directions. Thereby, the multimode dielectric resonator which can adjust two frequencies easily can be realized from the symmetry of the arrangement of the cutting surface with respect to the input terminal and the output terminal.

  In the present invention, the dielectric resonator body may be formed in a cylindrical shape. In the present invention, the dielectric resonator body may be formed to have a polygonal cross-sectional shape. In this case, the cross-sectional shape may be an octagon.

  In the present invention, the dielectric adjustment piece may be configured as a columnar shape arranged on the same central axis as the dielectric resonator body. In this case, the dielectric adjustment piece may be formed using the same dielectric material as that of the dielectric resonator body.

In the present invention, the dielectric resonator body may be configured such that the coupling coefficient of the first frequency and the second frequency is kept constant by adjusting the dielectric adjustment piece . Thereby, since the first frequency and the second frequency can be changed in conjunction with each other, it is possible to easily realize a filter characteristic capable of freely changing the pass frequency.

  On the other hand, the adjustment method of the multimode dielectric resonator according to the present invention is such that the dielectric resonator body that excites the resonance mode of the first frequency and the second frequency higher than the first frequency, respectively, Adjusting the frequency characteristics by adjusting the dielectric adjustment piece and changing the first frequency and the second frequency respectively while keeping the coupling coefficient of the first frequency and the second frequency constant It is.

  As described above, according to the present invention, the multi-mode dielectric resonator is configured by using the columnar dielectric resonator body and the dielectric adjustment piece disposed opposite to the top surface or the bottom surface thereof. The frequency characteristic for exciting the mode can be realized with a simple configuration, and the frequency characteristic can be easily controlled by adjusting the distance between the dielectric resonator body and the dielectric adjustment piece. In this case, if a part of the dielectric resonator main body is cut and each input / output terminal for the transmission signal is appropriately arranged, the frequencies corresponding to the plurality of resonance modes can be changed in conjunction with each other. That is, it is possible to realize a filter characteristic in which two frequencies change in the same direction while keeping the coupling coefficient constant. As described above, the present invention eliminates the need for complicated processing for frequency adjustment, ensures good manufacturability, easily adjusts high-accuracy frequency characteristics with low transmission loss, and can be applied to various filters. A body resonator can be realized.

  Embodiments of the present invention will be described with reference to the drawings. Hereinafter, two embodiments having different structures will be described with respect to the case where the present invention is applied to a dielectric resonator having two peaks in frequency characteristics corresponding to two resonance modes (double mode).

[First Embodiment]
The structure of the dielectric resonator according to the first embodiment will be described with reference to FIGS. FIG. 1 is a top view of the dielectric resonator according to the first embodiment, and FIG. 2 is a side view of the dielectric resonator of FIG. As shown in FIGS. 1 and 2, the dielectric resonator according to the first embodiment includes a dielectric resonator main body 10, a conductor case 11, a support base 12, an input terminal 13, an output terminal 14, A dielectric adjustment piece 15 and a support bar 16 are provided.

  The dielectric resonator body 10 has a shape in which a part of a column is cut, and is disposed at a substantially central portion in a cavity surrounded by a cylindrical conductor case 11. The bottom surface of the dielectric resonator body 10 is fixed by a support base 12 attached to the conductor case 11. The dielectric resonator body 10 is formed using a dielectric material having a predetermined dielectric constant. The dielectric resonator main body 10 and the external space are in a state of being electrically cut off by the surrounding conductor case 11. The support base 12 is made of alumina, for example, and has a cylindrical shape.

  The input terminal 13 and the output terminal 14 are respectively attached to the side surfaces of the conductor case 11. The input terminal 13 is a terminal to which an input signal supplied from the outside is supplied, and the output terminal 14 is a terminal that outputs an output signal excited in a plurality of resonance modes to the outside. The X axis and the Y axis are shown in the lower part of FIG. 1 for the sake of convenience. As viewed from the central axis of the dielectric resonator body 10, the position of the input terminal 13 is arranged in the X direction, and the position of the output terminal 14 is Arranged in the Y direction. That is, the input terminal 13 and the output terminal 14 are in a positional relationship orthogonal to each other within a plane including the circular cross section of the dielectric resonator body 10. The input terminal 13 and the output terminal 14 may be replaced with each other.

  The cutting surface 10a of the dielectric resonator body 10 is formed such that the normal line forms an angle of 45 degrees with respect to each of the X axis and the Y axis in the horizontal plane. Forming the cutting surface 10a at such an angle is an example of a structure for the dielectric resonator body 10 to excite two resonance modes. Since the cutting amount H of the cutting surface 10a shown in FIG. 1, that is, the distance from the outer peripheral position of the circular cross section of the dielectric resonator body 10 before cutting to the central position of the cutting surface 10a greatly affects the resonance mode characteristics. It is desirable to determine an optimum cutting amount H that provides desired characteristics.

  The dielectric adjustment piece 15 is disposed opposite to the upper surface of the dielectric resonator body 10 and has a cylindrical shape whose central axis coincides with that of the dielectric resonator body 10. In the first embodiment, the diameter of the circular cross section of the dielectric adjustment piece 15 is set to be sufficiently smaller than that of the dielectric resonator body 10, and the dielectric adjustment piece 15 is the same dielectric material as that of the dielectric resonator body 10. It is formed using. A support bar 16 is attached to the top of the dielectric adjustment piece 15, and the vertical position of the dielectric adjustment piece 15 can be changed by the support bar 16. Thereby, the distance D (refer FIG. 2) between the dielectric resonator main body 10 and the dielectric adjustment piece 15 can be adjusted freely.

  In the configuration of the first embodiment, the arrangement of the input terminal 13 and the output terminal 14 and the arrangement of the cutting surface 10a have a symmetrical relationship along the vertical direction, so that the dielectric adjustment piece 15 is displaced in the vertical direction. It has almost the same effect on the electric fields of the two resonance modes. As a result, the two frequencies corresponding to the two resonance modes change in conjunction with each other, and this will be described in detail later.

  Next, FIG. 3 is a diagram illustrating an equivalent circuit of the dielectric resonator according to the first embodiment. The equivalent circuit shown in FIG. 3 includes capacitances C3, C4, and C5 connected in series between the input terminal 13 and the output terminal 14, a capacitance C1 and an inductance L1 connected in parallel between the node N1 and the ground, and a node N2. And a capacitance C2 and an inductance L2 connected in parallel between the ground and the ground.

  Capacitance C1 and inductance L1 form a first resonance circuit corresponding to one resonance mode of the dielectric resonator. Capacitance C2 and inductance L2 constitute a second resonance circuit corresponding to the other resonance mode of the dielectric resonator. The capacitor C3 is a coupling capacitance between the input terminal 13 and the first resonance circuit, and the capacitance C5 is a coupling circuit between the output terminal 14 and the second resonance circuit. Further, the capacitance C4 is an intermittent coupling capacitance formed by the cutting surface 10a.

  The constants of the circuit elements shown in FIG. 3 vary depending on the material and size of the members constituting the dielectric resonator. In particular, the values of the capacitances C1, C2, C4 and the inductances L1, L2 change depending on the position and size of the cutting surface 10a formed on the dielectric resonator body 10, and the resonance mode characteristics are affected. It is important to form a smooth cutting surface 10a.

  Next, the characteristics of the dielectric resonator according to the first embodiment will be described with reference to FIGS. Here, as the sizes of the dielectric resonator body 10 and the dielectric adjustment piece 15, for example, the dielectric resonator body 10 has a diameter of about 40 mm and a height of about 10 mm, and the dielectric adjustment piece 15 has a diameter of about 40 mm. It is assumed that the height is set to about 0.25 mm at about 10 mm, and the adjustment range of the dielectric adjustment piece 15 is displaced in the range of the distance D between the dielectric resonator body 10 and 1 to 5 mm.

  FIG. 4 shows the frequency characteristics of the transmission signal in the dielectric resonator. The loss of the signal transmitted from the input terminal 13 to the output terminal 14 is shown in a graph in a relatively narrow frequency range around 2 GHz. Further, in FIG. 4, the frequency characteristics in the case where there are three types of distance D (D = 1, 3, 5 mm) are compared and shown. As can be seen from FIG. 4, at the first frequency on the low frequency side and the second frequency on the high frequency side, the loss has a peak close to 0 (dB), and the loss increases at other frequencies.

  The two peaks in the frequency characteristic of FIG. 4 are generated corresponding to the two resonance modes of the dielectric resonator. When the first frequency is FL and the second frequency is FH, there is a frequency difference of about 20 MHz between the two. As the distance D of the dielectric adjustment piece 15 increases to 1 mm, 3 mm, and 5 mm, both the first and second frequencies FL and FH in the frequency characteristics increase.

  Further, in the frequency characteristics of FIG. 4, there are downward peaks in addition to the two upward peaks of the frequencies FL and FH. The downward peak of these frequency characteristics is called an attenuation pole. In general, since the filter characteristic is required to be steep, it is preferable that an attenuation pole is present. The attenuation pole of the frequency characteristic can be generated according to the position of the cutting surface 10a formed in the dielectric resonator body 10.

  FIG. 5 shows the relationship between the change in the distance D and the frequency characteristics. As shown in FIG. 5, in addition to the first frequency FL and the second frequency FH, the change of the average frequency FA (FA = (FL + FH) / 2) with respect to the distance D is shown by a graph. Reflecting the frequency characteristics described above, it can be seen that the frequencies FL, FH, and FA gradually increase as the distance D increases. Further, the changes with respect to the distance D of the frequencies FL, FH, and FA are linked to each other with the same tendency, but this is based on the action of the displacement of the dielectric adjustment piece 15 with respect to the two resonance modes as described above. .

  FIG. 6 shows the relationship between the change in the distance D and the above-described average frequency FA and coupling coefficient k. Here, the coupling coefficient k is an amount that is obtained by k = (FH−FL) / FA and represents the degree of relative separation between the first frequency FL and the second frequency FH. Note that the frequency axis in FIG. 6 is represented by a scale in a narrower range than that in FIG. 5 in order to enlarge and show the change in the average frequency FA. It can be seen that the average frequency FA increases as the distance D decreases, and becomes maximum when D = 5 mm. It can also be seen that the coupling coefficient k stably maintains a value of about 0.01 within the entire range of the distance D.

  In the example of FIG. 6, the coupling coefficient k maintains a value of about 0.01. However, a different coupling coefficient k can be set by changing the cutting amount H (FIG. 1) with respect to the dielectric resonator body 10. When the coupling coefficient k is increased with reference to FIG. 6, the cutting amount H is increased, and when the coupling coefficient k is decreased, the cutting amount H is decreased. An appropriate value of the coupling coefficient k to be set is determined according to a frequency characteristic required in the circuit incorporating the dielectric resonator of the first embodiment.

  4 to 6 show examples of characteristics obtained by using the dielectric resonator according to the first embodiment. In practice, various characteristics can be realized according to design conditions. it can. In particular, the size of each of the dielectric resonator body 10 and the dielectric adjustment piece 15 has a great influence on the frequency characteristics, so it is desirable to set desired design conditions optimally.

  As described above, since the dielectric resonator according to the first embodiment has the characteristics shown in FIGS. 4 to 6, the first and second dielectric adjustment pieces 15 maintain the coupling coefficient k constant. The frequencies FL and FH can be adjusted in conjunction with each other. For example, if the filter is configured using the dielectric resonator according to the first embodiment, the pass frequency band including the first and second frequencies FL and FH can be freely varied. In this case, since the frequencies FL, FH, and FA (FIG. 6) can be finely changed with respect to the change in the distance D, application to a variable band filter capable of highly accurate frequency adjustment is facilitated. In addition, since the dielectric adjustment piece 15 that can be displaced in the vertical direction is used as the frequency adjustment means, it is possible to avoid loss of transmission signal and difficulty in processing when a structure such as a screw member or a cylindrical hole is adopted. it can.

  Next, a modification of the first embodiment will be described. FIG. 7 is a top view of a dielectric resonator according to a modification of the first embodiment, and FIG. 8 is a side view of the dielectric resonator of FIG. As shown in FIGS. 7 and 8, the modification of the first embodiment is a modification of the structure of the dielectric resonator body 10 shown in FIGS. In FIG. 8, the cutting surface 10b of the dielectric resonator body 10 is formed in a concave cross section when viewed from the side surface direction. That is, of the side surface of the dielectric resonator body 10, the vicinity of the center in the central axis direction is partially cut, and the upper surface side and the bottom surface side are not cut. 7 and 8, the structure is the same as that in FIGS. 1 and 2 except for the dielectric resonator body 10 and its cutting surface 10 b. The structure of the cutting surface 10b shown in FIGS. 7 and 8 is an example, and the position and width of the concave cross section can be changed. In the modification of the first embodiment, even when the cutting surface 10b shown in FIGS. 7 and 8 is formed, the characteristics as shown in FIGS. be able to.

[Second Embodiment]
Next, the structure of the dielectric resonator according to the second embodiment will be described with reference to FIGS. FIG. 9 is a top view of the dielectric resonator according to the second embodiment, and FIG. 10 is a side view of the dielectric resonator of FIG. The dielectric resonator according to the second embodiment includes a dielectric resonator body 20 having a shape different from that of the first embodiment. The conductor case 11, the support base 12, the input terminal 13, the output terminal 14, the dielectric adjustment piece 15, and the support bar 16 have the same structure as that of the first embodiment.

  As shown in FIG. 9, the dielectric resonator body 20 of the second embodiment has an octagonal cross-sectional shape instead of a cylinder, and is arranged so that its central axis is at the same position as in FIG. 1. . Further, in the dielectric resonator body 20 of FIG. 9, a cutting surface 20a is formed on one side in the same direction as the cutting surface 10a of FIG. In the cross section of the dielectric resonator body 20, one side of the cutting surface 20a is closer to the central axis by a distance H 'than the other side. Further, the dielectric adjustment piece 15 has the same structure as that shown in FIG. 1, and the support rod 16 is rotated with respect to the rotation axis in the central axis direction of the dielectric resonator main body 20, thereby The distance D (FIG. 10) can be adjusted.

  Next, characteristics of the dielectric resonator according to the second embodiment will be described with reference to FIGS. 11 and 12. FIG. 11 is a graph showing the frequency characteristics of the transmission signal in the dielectric resonator of the second embodiment, as in FIG. 4 of the first embodiment. In FIG. 11, as the distance D described above, two frequency characteristics of D = 1 mm and D = 4.5 mm are compared and shown. As can be seen from FIG. 11, the points having peaks on the low frequency side and the high frequency side are the same as in FIG. In FIG. 11, the frequency at which each peak appears and the characteristics of the attenuation region are different from those in FIG. 4, but this is due to a difference in conditions such as the size of each constituent member.

  FIG. 12 shows the relationship between the change in the distance D, the average frequency FA, and the coupling coefficient k in the dielectric resonator of the second embodiment, as in FIG. 6 of the first embodiment. As can be seen from FIG. 12, the average frequency FA increases as the distance D increases, and the coupling coefficient k remains substantially constant even when the distance D changes. As described above, the characteristics of FIG. 12 change with a tendency similar to that of FIG. 6 of the first embodiment.

  Next, a modification of the second embodiment will be described. FIG. 13 is a top view of a dielectric resonator according to a modification of the second embodiment, and FIG. 14 is a side view of the dielectric resonator of FIG. As shown in FIGS. 13 and 14, the modification of the second embodiment changes the structure of the dielectric resonator body 20 from the same viewpoint as the modification of the first embodiment shown in FIGS. 7 and 8. Is. In FIG. 14, the cutting surface 20 b of the dielectric resonator body 20 is formed in a concave cross section when viewed from the side surface direction, as in FIG. 8. 13 and 14, the structure is the same as that in FIGS. 9 and 10 except for the dielectric resonator body 20 and its cutting surface 20 b. The structure of the cutting surface 20b in FIGS. 13 and 14 is an example, and the position and width of the concave cross section can be changed.

  Next, characteristics of the dielectric resonator according to the modification of the second embodiment will be described with reference to FIGS. 15 and 16. FIG. 15 is a graph showing the frequency characteristics of the transmission signal in the modification of the second embodiment, as in FIG. In FIG. 15, as the above-mentioned distance D, two frequency characteristics of D = 1 mm and D = 4 mm are compared and shown. It can be seen that the same tendency as in the case of FIG.

  FIG. 16 shows the relationship between the change in the distance D, the average frequency FA, and the coupling coefficient k in the dielectric resonator according to the modification of the second embodiment, as in FIG. It can be seen that the same tendency as in the case of FIG.

  Although the contents of the present invention have been specifically described based on the above-described two embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. it can. For example, in each of the above-described embodiments, the case where the dielectric adjustment piece 15 is disposed to be opposed to the upper surfaces of the dielectric resonator bodies 10 and 20 has been described. However, the dielectric adjustment piece 15 can be changed by changing the structure of the support 12. May be configured to be opposed to the bottom surfaces of the dielectric resonator bodies 10 and 20. The effects in this case are generally the same as those in the above embodiments when other conditions are the same. In each of the above embodiments, the case where the dielectric adjustment piece 15 is formed in a cylindrical shape having a smaller diameter than the dielectric resonator bodies 10 and 20 has been described. However, the dielectric adjustment piece 15 is formed in another shape. This is not excluded. For example, the dielectric adjustment piece 15 may be formed in a shape whose cross section is a combination of polygons. Further, in each of the above embodiments, the case where the dielectric adjustment piece 15 is formed using the same dielectric material as the dielectric resonator bodies 10 and 20 has been described. The dielectric adjustment piece 15 may be formed using dielectric materials having different dielectric constants.

  On the other hand, although each said embodiment demonstrated the case where the dielectric resonator main bodies 10 and 20 were cut by cutting surface 10a, 10b, 20a, 20b, it is not limited to this cutting method. The arrangement and cutting method of the cutting surfaces 10a, 10b, 20a, and 20b of the dielectric resonator bodies 10 and 20 can be freely changed within a range in which the effects of the present invention can be obtained. In this case, in each of the above-described embodiments, the dielectric resonator main bodies 10 and 20 are configured to excite two resonance modes. However, by devising the cutting method, more resonance modes are excited and a plurality of peaks are obtained. You may implement | achieve the frequency characteristic which has. In addition, the formation of the above-described cutting surfaces 10a, 10b, 20a, and 20b is an example of a side surface structure for the dielectric resonator main bodies 10 and 20 to excite two resonance modes, and has different side surface structures. It may be adopted.

  Further, in each of the above embodiments, the configuration in which the frequency characteristic is adjusted by the dielectric adjustment piece 15 has been described. However, in addition to the dielectric adjustment piece 15, another frequency adjustment mechanism may be provided. That is, in the dielectric adjustment piece 15, the two frequencies FL and FH change in conjunction with each other. However, when both of them need to be changed individually, the adjustment can be performed using the above-described frequency adjustment mechanism. For example, a frequency adjustment mechanism made of a metal screw at a position facing the input terminal 13 and the output terminal 14 (wall surface of the opposite conductor case 11), or a frequency adjustment mechanism in which a metal piece and a dielectric piece are loaded on the tip of the screw. Can be provided. Such a frequency adjustment mechanism can be freely installed, but it is assumed that it is within a range where the effects of the present invention can be obtained.

It is a top view of the dielectric resonator of the first embodiment. It is a side view of the dielectric resonator of FIG. It is a figure which shows the equivalent circuit of the dielectric resonator of 1st Embodiment. It is a figure which shows the frequency characteristic of the transmission signal in the dielectric resonator of 1st Embodiment. It is a figure which shows the relationship between distance D and a frequency characteristic in the dielectric resonator of 1st Embodiment. It is a figure which shows the relationship between the change of the distance D, the average frequency FA, and the coupling coefficient k in the dielectric resonator of 1st Embodiment. It is a top view of the dielectric resonator which concerns on the modification of 1st Embodiment. It is a side view of the dielectric resonator of FIG. It is a top view of the dielectric resonator of 2nd Embodiment. FIG. 10 is a side view of the dielectric resonator shown in FIG. 9. It is a figure which shows the frequency characteristic of the transmission signal in the dielectric resonator of 2nd Embodiment. It is a figure which shows the relationship of the change of the distance D, the average frequency FA, and the coupling coefficient k in the dielectric resonator of 2nd Embodiment. It is a top view of the dielectric resonator which concerns on the modification of 2nd Embodiment. It is a side view of the dielectric resonator of FIG. It is a figure which shows the frequency characteristic of the transmission signal in the dielectric resonator which concerns on the modification of 2nd Embodiment. It is a figure which shows the relationship of the change of distance D, average frequency FA, and coupling coefficient k in the dielectric resonator which concerns on the modification of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 20 ... Dielectric resonator main body 10a, 10b, 20a, 20b ... Cutting surface 11 ... Conductor case 12 ... Support stand 13 ... Input terminal 14 ... Output terminal 15 ... Dielectric adjustment piece 16 ... Support rod

Claims (10)

A columnar dielectric resonator body fixed in a cavity surrounded by conductors and exciting a plurality of resonance modes;
A dielectric adjustment piece arranged to be opposed to an upper surface or a bottom surface of the dielectric resonator body, and configured to adjust a distance from the dielectric resonator body; and
Equipped with a,
The dielectric resonator body excites the resonance mode of a first frequency and a second frequency higher than the first frequency, respectively, and adjusts the dielectric adjustment piece to adjust the first frequency and the first frequency. A multi-mode dielectric resonator, wherein each of the two frequencies changes .   The multimode dielectric resonator according to claim 1, wherein the plurality of resonance modes are excited by cutting a part of the dielectric resonator body, and the frequency characteristic has an attenuation pole.   An input terminal and an output terminal are attached to the conductor on the side surface side of the dielectric resonator body, and directions connecting the input terminal and the output terminal from the central axis are orthogonal to each other in a circular cross section of the dielectric resonator body The multimode dielectric resonator according to claim 2, wherein a normal line of the cut surface of the dielectric resonator body forms an angle of about 45 degrees with respect to the two directions.   4. The multimode dielectric resonator according to claim 1, wherein the dielectric resonator body is formed in a cylindrical shape.   4. The multimode dielectric resonator according to claim 1, wherein the dielectric resonator body has a polygonal cross-sectional shape.   The multimode dielectric resonator according to claim 5, wherein the cross-sectional shape is an octagon.   The multimode dielectric resonator according to claim 1, wherein the dielectric adjustment piece has a cylindrical shape arranged on the same central axis as the dielectric resonator main body.   The multimode dielectric resonator according to claim 7, wherein the dielectric adjustment piece is formed using the same dielectric material as that of the dielectric resonator body. 9. The dielectric resonator body according to claim 1 , wherein the coupling coefficient between the first frequency and the second frequency is kept constant by adjusting the dielectric adjustment piece . A multimode dielectric resonator according to claim 1. A method for adjusting a multimode dielectric resonator according to claim 2, comprising:
The dielectric adjustment piece is adjusted for the dielectric resonator body that excites the resonance mode of the first frequency and the second frequency higher than the first frequency, and the first frequency and the first frequency are adjusted. A frequency characteristic is adjusted by changing each of the first frequency and the second frequency while keeping a coupling coefficient of two frequencies constant.

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