JP2004312288A - Dielectric resonator, dielectric filter, composite dielectric filter, and communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric resonator wherein two resonance modes are coupled with a prescribed coupling amount and respective resonance frequencies have differences, and to provide a dielectric filter employing the dielectric resonator to obtain a desired filter characteristic, a composite dielectric filter and a small-sized low cost communication apparatus employing them. <P>SOLUTION: The dielectric resonator is characterized in that a hole 15 is formed in a position different from both a first virtual plane VS1 including two ridges in parallel with each other and in a diagonal positional relation and a second virtual plane VS2 including the two other ridges in parallel with the two ridges and in a diagonal positional relation. Further, the dielectric resonator is characterized in that the coupling coefficient of the two resonance modes depends on a distance D between the center (o) of the dielectric resonator and the hole 15, and a difference between the resonance frequencies of the two resonance modes is decided depending on deviation (d) from the virtual plane VS2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dielectric resonator operating in multiple modes, a dielectric filter including the same, a composite dielectric filter, and a communication device.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a multi-mode dielectric resonator in which one dielectric block resonates in a plurality of resonance modes has been used (for example, Patent Document 1).
In the dielectric resonator disclosed in Patent Literature 1, an inclined plane is provided on at least a part of a ridge portion of a substantially rectangular parallelepiped dielectric block so that two resonance modes are coupled to each other.
[0003]
[Patent Document 1]
JP 2002-151906 A
[Problems to be solved by the invention]
However, in the structure of the dielectric resonator disclosed in Patent Literature 1, when two predetermined resonance modes are coupled to each other among the three resonance modes that occur, the two resonance modes are deleted along with the removal of the dielectric portion. The resonance frequency of the resonance mode increases. That is, the coupling amount and the resonance frequency are linked, and it is not possible to determine both independently.
[0005]
Further, in the actual use state of the dielectric resonator, it is necessary to make two resonance frequencies to be coupled different depending on the coupling condition with another resonator and the shape of the cavity. However, in the dielectric resonator disclosed in Patent Literature 1, the resonance frequencies of the two resonance modes to be coupled both change in the ascending direction with the enlargement of the oblique plane. Both rise and there is no difference between them. Therefore, when a dielectric filter is configured, desired filter characteristics cannot be designed and manufactured with a high degree of freedom. Furthermore, a communication device using the dielectric filter or the composite dielectric filter cannot be configured to be small and low-cost.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a dielectric resonator which solves the above-mentioned problem and allows the coupling amount and the resonance frequency to be determined independently.
[0007]
Another object of the present invention is to provide a dielectric resonator in which two resonance modes are coupled with a predetermined amount of coupling and have a difference in their respective resonance frequencies, and a desired filter characteristic is obtained by using the dielectric resonator. It is an object of the present invention to provide a dielectric filter, a composite dielectric filter, and a small and low-cost communication device including the same.
[0008]
[Means for Solving the Problems]
According to the present invention, there is provided a TE01δ multimode dielectric resonator having a substantially rectangular parallelepiped shape, which is disposed in a cavity, and includes a first ridge including two ridges which are parallel to each other and have a diagonal positional relationship with each other. It is characterized in that holes are provided at positions different from both the virtual plane and the second virtual plane including the other two parallel and diagonal positional relations different from each other.
[0009]
If holes are provided at different positions from the first and second imaginary planes including the two ridges which are parallel to each other and are in a diagonal positional relationship as described above, deviation from the position where the first and second imaginary planes intersect will occur. Since there is a hole at the position where the two resonance modes are located, a difference occurs between the frequencies of the two coupling modes due to the two resonance modes, and the two resonance modes are coupled to each other. In addition, a difference occurs in the effective permittivity of a portion where the electric field vector of the two coupled resonance modes passes, and a difference occurs in the resonance frequency of the two resonance modes.
[0010]
Further, the present invention provides a TE01δ multi-mode dielectric resonator which is disposed in a cavity and has a substantially rectangular parallelepiped shape as a whole. The dielectric resonator has a surface which is separated from a central portion of the surface and included in the surface. And a groove extending at a predetermined depth substantially parallel to the ridge and passing through a position away from the ridge.
[0011]
As described above, the groove extending parallel to the ridge included in the dielectric resonator at a position away from the central portion of the outer surface of the dielectric resonator causes a difference in the frequency of the two coupling modes due to the two resonance modes. The two resonance modes are coupled to each other. Further, a difference occurs in the effective permittivity of the two coupled resonance modes with respect to the electric field vector, so that the two resonance modes can have different resonance frequencies.
[0012]
Also, the present invention provides a dielectric filter including the above-described dielectric resonator and external coupling means externally coupled to the dielectric resonator, and a composite dielectric including a plurality of sets of the dielectric filter. It is characterized by constituting a filter.
[0013]
Further, the present invention is characterized in that a communication device is configured by providing the above-described dielectric filter or composite dielectric filter in a high-frequency circuit unit.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
A dielectric resonator according to a first embodiment will be described with reference to FIGS.
FIG. 1 is an exploded perspective view showing a basic configuration of a dielectric resonator disposed in a cavity and a configuration of a main part of a dielectric resonator device including the same. In this example, the dielectric core 10 is arranged inside the cavity 1 to constitute a dielectric resonator device. The outer shape of the dielectric core 10 has a substantially cubic shape. This dielectric core 10 is joined to the support plate 3. As the support plate 3, a ceramic plate having a low dielectric constant and a linear expansion coefficient similar to that of the dielectric core 10 is used. The dielectric core 10 is bonded to the support plate 3 with an adhesive or bonded by baking glass grace.
[0015]
The cavity 1 is a metal molded body, and its inner surface has a substantially rectangular parallelepiped shape. A conductor film such as a silver electrode is formed on the inner and outer surfaces of the cavity. Four support columns 2 are arranged on the inner bottom surface of the cavity 1, and the support plate 3 is supported via the support columns 2. A cover is attached to the upper opening surface of the cavity 1.
[0016]
Thus, the dielectric resonator 10 is arranged at the center of the cavity 1. In the figure, a loop symbol symbolizes the shape of the electric field distribution of the three resonance modes generated in the dielectric resonator 10. That is, three resonance modes of a TE01δx mode in which an electric field rotates along a plane perpendicular to the x-axis, a TE01δy mode in which an electric field rotates along a plane perpendicular to the y-axis, and a TE01δz mode in which an electric field rotates along a plane perpendicular to the z-axis. Occurs. Of course, higher-order resonance modes of these resonance modes also occur, but here, the fundamental mode is used.
[0017]
2 to 4 show examples of the electromagnetic field distribution of the above three resonance modes. 2 shows the TE01δx mode, FIG. 3 shows the TE01δy mode, and FIG. 4 shows the TE01δz mode. In these figures, solid arrows represent lines of electric force, and broken arrows represent lines of magnetic force. The cavities are omitted in these figures as in the case of FIG.
[0018]
In the examples shown in FIGS. 1 to 4, if the dielectric resonator 10 has a cubic shape, the electromagnetic field distributions of the three resonance modes are orthogonal to each other, so that they are independent. The resonance frequencies of the three resonance modes are equal. The following configuration is used to couple two resonance modes out of the three resonance modes.
[0019]
FIG. 5A shows the directions in which the electric fields of the TE01δx mode and the TE01δy mode rotate in a plane. (B) shows the directions in which the electric fields of the TE01δx + y mode (even mode) and the TE01δx-y mode (odd mode), which are coupling modes of the two resonance modes, rotate.
[0020]
FIG. 6 is a perspective view of a dielectric resonator in which two resonance modes are coupled with a predetermined coupling amount and the respective resonance frequencies are set to predetermined values. A first virtual surface VS1 including two edges E1 and E3 parallel and diagonal to each other of the dielectric resonator 10 and another two edges parallel to the edges E1 and E3 and in a diagonal relationship to each other. The holes 15 are provided at different positions from any of the second virtual planes VS2 including E2 and E4. In this example, the hole 15 forms a bottomed hole having a circular cross section extending in a direction parallel to the four ridges E1 to E4.
[0021]
FIG. 7 is a top view of the dielectric resonator 10 shown in FIG. Arrows shown in (A) and (B) indicate directions of electric field vectors (loops) of two resonance modes (TE01δx mode and TE01δy mode) to be coupled. When the hole 15 is provided at a position shifted from the intersection of the two virtual planes VS1 and VS2, the electric fields of the two coupling modes TE01δx + y mode and TE01δx-y mode as shown in FIG. , An unbalanced perturbation occurs, and the two resonance modes are coupled to each other.
[0022]
If the hole 15 is provided at the position of the virtual plane VS2 as shown in (A), the hole 15 acts equally on the electric fields of the TE01δx mode and the TE01δy mode. The resonance frequency rises equally.
[0023]
On the other hand, as shown in FIG. 7B, when the hole 15 is provided at a position shifted from the virtual plane VS2, there is a difference in the degree of influence of the two resonance modes on the electric field. In this example, the hole 15 is present at a portion where the electric field intensity of the TE01δy mode is relatively low and is present at a portion where the electric field intensity of the TE01δx mode is relatively high. Therefore, the effective dielectric constant with respect to the electric field of the TE01δx mode is reduced, and The resonance frequency becomes relatively higher than the resonance frequency of the TE01δy mode.
[0024]
FIG. 7C shows the position of the hole 15 in a positional relationship with respect to two virtual planes. As the distance D in the direction along the virtual plane VS2 from the center 15 of the dielectric resonator 10 (the straight line intersecting the two virtual planes VS1 and VS2) increases, the frequency difference between the two coupling modes increases. The amount of binding increases. Further, as the deviation d from the virtual plane VS2 increases, the difference between the resonance frequencies of the two resonance modes increases. Further, as the volume determined by the inner diameter and the depth of the hole 15 increases, the above-described operation becomes more remarkable. Therefore, the resonance frequency and the coupling amount of the two resonance modes can be arbitrarily determined according to the position and the size of the hole 15.
[0025]
Next, a dielectric resonator according to a second embodiment will be described with reference to FIGS.
FIG. 8 is a perspective view of the dielectric resonator. Unlike the dielectric resonator shown in the first embodiment, two holes 15 and 15 'are provided.
[0026]
FIG. 9 is a top view of the dielectric resonator. When the two holes 15, 15 'are provided at the position of the virtual plane VS2 as shown in FIG. 9A, the holes 15, 15' are equivalent to the electric fields of the TE01.delta.x mode and the TE01.delta.y mode. In operation, the resonance frequencies of the two resonance modes rise equally.
[0027]
On the other hand, as shown in FIG. 9B, when the holes 15 and 15 'are provided at positions shifted from the virtual plane VS2, a difference occurs in the degree of influence of the two resonance modes on the electric field. In this example, the holes 15, 15 'are present in a portion where the electric field intensity of the TE01δy mode is relatively low and are present in a portion where the electric field intensity of the TE01δx mode is relatively high. Relatively high.
[0028]
FIG. 9C shows the positions of the holes 15, 15 'in a positional relationship with respect to the two virtual planes. The larger the distances D and D 'in the direction along the virtual plane VS2 from the center o of the dielectric resonator 10 (the straight line intersecting the two virtual planes VS1 and S2) with the holes 15, 15', the larger the two coupling modes. Since the frequency difference increases, the coupling amount increases. Further, the difference between the resonance frequencies of the two resonance modes increases as the shift amounts d and d 'from the virtual plane VS2 increase. Further, as the volume determined by the inner diameter and the depth of the holes 15, 15 'becomes larger, the above-mentioned effect becomes more remarkable. Therefore, the resonance frequencies and coupling amounts of the two resonance modes can be arbitrarily determined according to the positions and sizes of the holes 15, 15 '.
[0029]
If the two holes 15 and 15 'are provided in this manner, for example, the holes 15 are provided at predetermined positions and at predetermined depths in the first stage when adjusting the coupling amount and the resonance frequency, and the characteristics of the dielectric resonator are improved. After measurement, if the other hole 15 ′ is provided at a predetermined position by a predetermined depth in order to correct a deviation from a predetermined characteristic value, the coarse adjustment and the fine adjustment are combined, and The characteristic adjustment is completed.
[0030]
FIG. 10 is a perspective view of the dielectric resonator according to the third embodiment. In the first and second embodiments, an example has been described in which the coupling amount and the resonance frequency are determined for two of the three resonance modes. However, the coupling amount and the resonance frequency of the second and third resonance modes are also determined. In order to perform the adjustment, holes may be provided on two orthogonal outer surfaces of the dielectric resonator 10 as shown in FIG. In the example shown in FIG. 10, the coupling amounts of the TE01δx mode and the TE01δy mode and the respective resonance frequencies are determined by the holes 15 and 15 ′, and the coupling amounts of the TE01δx mode and the TE01δz mode and the respective resonance frequencies are determined by the holes 16 and 16 ′. be able to.
[0031]
FIG. 11 is a top view of the dielectric resonator according to the fourth embodiment. In this example, holes 15a and 15a 'are provided for coarse adjustment, and holes 15b and 15b' are provided for fine adjustment. The holes 15b and 15b 'for fine adjustment are provided near another orthogonal virtual surface VS1 different from the virtual surface VS2 near the holes 15a and 15a' for coarse adjustment. For example, assuming that the coupling amount of the two resonance modes before the hole is provided is 0 (coupling coefficient k = 0%) and the resonance frequencies of the two resonance modes are f1 and f2, the holes 15a and 15a 'are provided. When the coupling amount (e.g., coupling coefficient k '= 2%) is reached and the resonance frequencies change to f1' and f2 ', respectively, then, to reduce the coupling amount to a predetermined coupling amount (e.g., coupling coefficient k "= 1%), The fine adjustment holes 15b and 15b 'are provided, so that the two resonance frequencies also change to f1 "and f2". Therefore, in anticipation of the change in the resonance frequency at the time of the fine adjustment, the f1 "and f2" are set. Should be determined so that the target resonance frequency is obtained and the coupling coefficient k ″ becomes the target coupling coefficient by adjusting the positions and sizes of the fine adjustment holes 15b and 15b ′.
[0032]
In addition, by providing each hole in the relationship of the diagonal positions, not only the adjustment range is widened, but even if the adjustment amount is increased, the structural symmetry of the dielectric resonator 10 is not largely broken, This has the effect of suppressing the occurrence of spurious modes.
[0033]
Next, a dielectric resonator according to a fifth embodiment will be described with reference to FIGS.
FIG. 12 is a perspective view of the dielectric resonator. In the example of (A), the groove 11 having a predetermined depth is provided at a position away from the central portion o of the predetermined surface of the dielectric resonator 10 and extends in parallel with the ridge E4. In the example shown in (B), two grooves 11, 11 'are similarly provided.
[0034]
FIG. 13 is a top view showing the positional relationship between the electric field distribution and the groove of two resonance modes to be coupled by the dielectric resonator. Since the grooves 11, 11 'are provided at positions distant from the center of the predetermined surface and parallel to the ridge, two coupling modes based on two resonance modes (TE01δx mode, TE01δy mode) are provided. And the two resonance modes are coupled to each other. In addition, a difference occurs in the effective permittivity of a portion where the electric field vector of the two coupled resonance modes passes, and a difference occurs in the resonance frequency of the two resonance modes.
[0035]
When the positions of the grooves 11 and 11 'are represented by distances S and S' from the ridges E1 and E3 as shown in FIG. 13C, the electric field of the two coupling modes decreases as the distances S and S 'decrease. And the amount of coupling increases. Also, as S and S 'are increased, the difference between the effects of the two resonance modes on the electric field is increased, and the difference between the resonance frequencies is increased. Further, the influence on the coupling amount and the resonance frequency difference also changes depending on the ratio between the width and the depth of the grooves 11, 11 '.
[0036]
As described above, since the coupling amount and the difference between the two resonance frequencies change together depending on the positions of the grooves 11, 11 ', both cannot be determined completely independently. However, the width and depth of the grooves 11, 11' are also adjusted. By doing so, the resonance frequencies of the two resonance modes and their coupling amounts can be determined with a certain degree of freedom. For example, if the groove 11 is provided for coarse adjustment and the groove 11 'is provided for fine adjustment, the resonance frequencies of the two resonance modes and the coupling amount thereof can be determined with higher accuracy.
[0037]
If a fine adjustment groove is provided on the side opposite to 11 'as a virtual plane VS1 boundary as indicated by 11 ", the change in the resonance frequency difference between the two resonance modes can be made to act in a decreasing direction. .
[0038]
In the example shown in FIG. 13D, grooves 11a and 11a 'are provided for coarse adjustment, and grooves 11b and 11b' are provided for fine adjustment. The fine adjustment grooves 11b and 11b 'are provided near another orthogonal virtual surface VS2 different from the virtual surface VS1 near the coarse adjustment grooves 11a and 11a'. By providing each groove in the relationship of the diagonal positions as described above, not only the adjustment range is widened, but even if the adjustment amount is increased, the structural symmetry of the dielectric resonator 10 is not largely broken, and the spurious mode This has the effect of suppressing the occurrence of.
[0039]
Next, a configuration of a dielectric filter according to a sixth embodiment will be described with reference to FIG. FIG. 14 shows the positional relationship between a dielectric resonator in a cavity and a coupling loop coupled thereto. This dielectric resonator 10 is the same as the dielectric resonator shown in FIG. The cavity is omitted in the figure. One end of each of the coupling loops Ky and Kz is connected to the center conductor of the coaxial connector attached to the cavity, and the other end is connected to the inner surface of the cavity. The coupling loop Ky points its loop plane to the xz plane. The coupling loop Kz has its loop plane oriented in the xy plane. Therefore, the coupling loop Ky magnetically couples to the TE01δy mode, and the coupling loop Kz magnetically couples to the TE01δz mode.
[0040]
As already described with reference to FIG. 10, the TE01δx mode is coupled to the TE01δy mode and is also coupled to the TE01δz mode. Therefore, between the two coupling loops Ky and Kz, the TE01δy mode resonator → TE01δx mode resonator → TE01δz mode There are equivalently three resonators coupled in the order of the resonators. As a result, a filter having band-pass filter characteristics composed of three stages of resonators can be configured.
[0041]
Next, the configurations of the composite dielectric filter and the communication device according to the seventh embodiment are shown in FIG.
Here, the duplexer includes a transmission filter and a reception filter. Each of the transmission filter and the reception filter is a filter having the above-described configuration. The phase adjustment is performed between the output port of the transmission filter and the input port of the reception filter so that the transmission signal does not go to the reception filter side and the reception signal does not go to the transmission filter side. A transmission circuit is connected to a transmission signal input port of the duplexer, and a reception circuit is connected to a reception signal output port. An antenna is connected to the antenna port. Thus, a communication device including the dielectric resonator according to the present invention is configured.
[0042]
【The invention's effect】
According to the present invention, holes are provided at different positions from the first and second imaginary planes including two ridges of the substantially rectangular parallelepiped dielectric resonator, which are parallel and diagonal to each other, The two resonance modes can be coupled to each other, and the resonance frequencies of the two resonance modes can have a difference.
[0043]
Further, according to the present invention, by forming a groove extending from the center portion of the outer surface of the dielectric resonator and away from the ridge included in the surface and extending parallel to the ridge at a predetermined depth. In addition, the two resonance modes can be coupled to each other, and the resonance frequencies of the two resonance modes can have a difference.
[0044]
Further, according to the present invention, a dielectric filter having desired filter characteristics and a composite dielectric filter having the above-described dielectric resonator device and external coupling means externally coupled thereto can be easily obtained.
[0045]
Further, according to the present invention, a compact and low-cost communication device can be configured by providing the above-described dielectric filter or composite dielectric filter in a high-frequency circuit section.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a basic structure of a dielectric resonator according to a first embodiment. FIG. 2 is a diagram showing an electromagnetic field distribution in a TE01δx mode. FIG. 3 is a diagram showing an electromagnetic field distribution in a TE01δy mode. FIG. 4 is a view showing an electromagnetic field distribution of a TE01δz mode. FIG. 5 is a view showing directions of electric fields of two resonance modes and a coupling mode thereof. FIG. 6 is a perspective view of a dielectric resonator. FIG. FIG. 8 is a view showing an electric field distribution of two resonance modes and a positional relationship between holes. FIG. 8 is a perspective view of a dielectric resonator according to a second embodiment. FIG. 9 is a view showing two resonance modes and directions of electric fields of the coupled modes. FIG. 10 is a perspective view of a dielectric resonator according to a third embodiment. FIG. 11 is a diagram showing the electric field distribution and the positional relationship of holes in two resonance modes to be coupled by the dielectric resonator according to the fourth embodiment. FIG. 12 is a perspective view of a dielectric resonator according to a fifth embodiment. FIG. 13 is a diagram showing directions of electric fields of two resonance modes and a coupling mode thereof. FIG. 14 is a perspective view showing a configuration of a main part of a dielectric filter according to a sixth embodiment. FIG. 15 is a seventh embodiment. Showing the configuration of a composite dielectric filter and a communication device according to the present invention.
10-dielectric resonator 11, 11 ', 11a, 11a', 11b, 11b'-groove 15, 15 ', 15a, 15a', 15b, 15b'-hole VS1, VS2-virtual plane E1, E2, E3 E4-ridge

Claims (5)

In a TE01δ multi-mode dielectric resonator which is disposed in a cavity and has a substantially rectangular parallelepiped shape as a whole,
A first imaginary surface including two edges parallel and diagonal to each other of the dielectric resonator, and two other edges parallel to each other and diagonally different from each other; A dielectric resonator, wherein holes are provided at positions different from any of the second virtual planes. In a TE01δ multi-mode dielectric resonator which is disposed in a cavity and has a substantially rectangular parallelepiped shape as a whole,
A groove is provided on the surface of the dielectric resonator, the groove extending from the center of the surface and away from a ridge included in the surface and extending substantially parallel to the ridge at a predetermined depth. And a dielectric resonator. 3. A dielectric filter comprising: the dielectric resonator according to claim 1; and external coupling means externally coupled to the dielectric resonator. A composite dielectric filter comprising a plurality of sets of the dielectric filters according to claim 3 and sharing one external coupling means of each of the dielectric filters. A communication device comprising the dielectric filter according to claim 3 or the composite dielectric filter according to claim 4 in a high-frequency circuit unit.

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