JP4059126B2 - Dielectric resonator, dielectric filter, composite dielectric filter, and communication device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dielectric resonator that operates in multiple modes, a dielectric filter including the dielectric resonator, a composite dielectric filter, and a communication device.
[0002]
[Prior art]
Conventionally, a multi-mode dielectric resonator in which one dielectric block is resonated in a plurality of resonance modes has been used (for example, Patent Document 1).
In the dielectric resonator disclosed in Patent Document 1, an oblique plane is provided on at least a part of the ridge portion of a substantially rectangular parallelepiped dielectric block so that two resonance modes are coupled to each other.
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 2002-151906
[Problems to be solved by the invention]
However, in the structure of the dielectric resonator disclosed in Patent Document 1, when two predetermined resonance modes among the three generated resonance modes are coupled to each other, the two of the two resonance modes are removed along with the deletion of the dielectric portion. The resonance frequency of the resonance mode increases. That is, the amount of coupling and the resonance frequency are interlocked, and the two cannot be determined independently.
[0005]
Further, in the actual usage state of the dielectric resonator, it is necessary to make the two resonance frequencies to be coupled differ depending on the coupling conditions with other resonators and the shape of the cavity. However, in the dielectric resonator shown in Patent Document 1, as the oblique plane is enlarged, the resonance frequencies of the two resonance modes to be coupled both change in the upward direction. 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 in a small size and at a low cost.
[0006]
Accordingly, an object of the present invention is to provide a dielectric resonator in which the above-described problems are solved and the coupling amount and the resonance frequency can be determined independently.
[0007]
Another object of the present invention is to obtain a dielectric resonator that couples two resonance modes with a predetermined coupling amount and has a difference between the resonance frequencies, and a desired filter characteristic thereby. 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]
The present invention relates to a TE01δ multimode dielectric resonator having a substantially rectangular parallelepiped shape that is disposed in a cavity in a state of being separated from the wall surface of the cavity. At a position different from any of the first virtual surface including the two ridges and the second virtual surface including the other two ridges that are different from each other in parallel and diagonal positions . And includes a straight line intersecting the first and second imaginary planes at a position different from any of the other two imaginary planes that bisect the angle formed by the first and second imaginary planes. It is characterized by providing holes.
[0009]
In this way, the first and second imaginary planes including two ridges that are parallel and diagonal to each other are located at different positions , and the first and second imaginary planes intersect with each other. If a hole is provided at a different position from any of the other two virtual planes that bisect the angle formed by the first and second virtual planes, there will be a difference in the frequency of the two coupled modes due to the two resonance modes. As a result, the two resonance modes are coupled to each other. Further, a difference occurs in the effective dielectric constant at a portion through which the electric field vectors of the two resonance modes to be coupled pass, and a difference occurs in the resonance frequency of the two resonance modes.
[0010]
Further, the present invention provides a TE01δ multimode dielectric resonator having a substantially rectangular parallelepiped shape disposed in a cavity in a state separated from a wall surface of the cavity . And a groove extending through the position away from the ridge included in the surface and extending substantially parallel to the ridge at a predetermined depth.
[0011]
In this way, the groove extending in parallel to the ridge included in the surface at a position away from the center of the outer surface of the dielectric resonator causes a difference in the frequency of the two coupling modes by the two resonance modes. The two resonance modes are coupled to each other. Further, a difference occurs in the effective dielectric constant with respect to the electric field vector of the two resonance modes to be coupled, so that the resonance frequencies of the two resonance modes can be made different.
[0012]
The present invention also provides a dielectric filter comprising the dielectric resonator and an external coupling means for external coupling to the dielectric resonator, and a composite dielectric comprising a plurality of sets of the dielectric filter. It is characterized by constituting a filter.
[0013]
In addition, the present invention is characterized in that a communication device is configured by including the dielectric filter or the composite dielectric filter in a high-frequency circuit section.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The dielectric resonator according to the 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, a dielectric resonator device is configured by disposing the dielectric core 10 inside the cavity 1. The outer shape of the dielectric core 10 has a substantially cubic shape. The dielectric core 10 is bonded to the support plate 3. As the support plate 3, a ceramic plate having a low dielectric constant and having 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. Conductive films such as silver electrodes are 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]
In this way, the dielectric resonator 10 is arranged at the center of the cavity 1. The loop symbol in the figure 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 TE01δx mode in which an electric field rotates along a plane perpendicular to the x axis, TE01δy mode in which an electric field rotates along a plane perpendicular to the y axis, and 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 the fundamental mode is used here.
[0017]
2 to 4 show examples of electromagnetic field distributions in the 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 indicate electric lines of force, and broken arrows indicate lines of magnetic force. Note that the cavities are omitted in these figures as in the case of FIG.
[0018]
In the example 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 the same. In order to couple two of the three resonance modes, the following configuration is used.
[0019]
FIG. 5A shows the directions in which the electric fields of the TE01δx mode and the TE01δy mode rotate by planes. (B) shows the direction in which the electric field rotates in the TE01δx + y mode (even mode) and TE01δx-y mode (odd mode), which are coupled modes of these two resonance modes.
[0020]
FIG. 6 is a perspective view of a dielectric resonator in which two resonance modes are coupled with a predetermined coupling amount and each resonance frequency is set to a predetermined value. The first imaginary plane VS1 including two ridges E1 and E3 that are parallel and diagonal to each other of the dielectric resonator 10 and the other two ridges that are parallel to the ridges E1 and E3 and are diagonal to each other A hole 15 is provided at a position different from any of the second virtual plane 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 edges E1 to E4.
[0021]
FIG. 7 is a top view of the dielectric resonator 10 shown in FIG. The arrows shown in (A) and (B) indicate the directions of the electric field vectors (loops) of the two resonance modes (TE01δx mode and TE01δy mode) to be coupled. As described above, when the hole 15 is provided at a position shifted from the intersecting position of the two virtual planes VS1 and VS2, as shown in FIG. 5B, the electric fields of the two coupled modes TE01δx + y mode and TE01δx-y mode are obtained. 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, if 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, since the hole 15 exists in a portion where the electric field strength of the TE01δx mode is relatively low and exists in a portion where the electric field strength of the TE01δx mode is relatively high, the effective dielectric constant with respect to the electric field of the TE01δx mode is reduced. The resonance frequency is 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 the two virtual planes. Since the distance D in the direction along the virtual plane VS2 from the center 15 of the dielectric resonator 10 (the straight line where the two virtual planes VS1 and VS2 intersect) o increases, the frequency difference between the two coupling modes increases. The amount of binding increases. Further, as the deviation d from the virtual surface VS2 increases, the difference between the resonance frequencies of the two resonance modes increases. Furthermore, the above action becomes more remarkable as the volume determined by the inner diameter and depth of the hole 15 increases. Accordingly, the resonance frequency and the coupling amount of the two resonance modes can be arbitrarily determined by the position and 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 and 15 'are provided at the position of the virtual plane VS2 as shown in FIG. 9A, the holes 15 and 15' are equivalent to the electric fields of the TE01δx mode and the TE01δy mode. In order to act, the resonance frequency of these two resonance modes rises equally.
[0027]
On the other hand, as shown in FIG. 9B, if the holes 15 and 15 'are provided at positions 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, since the holes 15 and 15 'are present in a portion where the electric field strength of the TE01δx mode is relatively low and are present in a portion where the electric field strength of the TE01δx mode is relatively high, the resonance frequency of the TE01δx mode is higher than the resonance frequency of the TE01δy mode. Relatively high.
[0028]
FIG. 9C shows the positions of the holes 15 and 15 ′ in a positional relationship with respect to the two virtual surfaces. As the distances D and D ′ in the direction along the virtual plane VS2 from the center (the straight line where the two virtual planes VS1 and S2 intersect) o of the holes 15 and 15 ′ increase from the center o, Since the frequency difference increases, the amount of coupling increases. In addition, the difference between the resonance frequencies of the two resonance modes increases as the deviation amounts d and d ′ from the virtual surface VS2 increase. Furthermore, the above action becomes more remarkable as the volume determined by the inner diameter and depth of the holes 15 and 15 'increases. Accordingly, the resonance frequency and the coupling amount of the two resonance modes can be arbitrarily determined by the positions and sizes of the holes 15 and 15 '.
[0029]
If the two holes 15 and 15 'are provided in this way, for example, the hole 15 is provided at a predetermined depth at a predetermined position in the first stage when adjusting the coupling amount and the resonance frequency, and the characteristics of the dielectric resonator are improved. After the measurement, in order to correct the deviation from the predetermined characteristic value, if the other hole 15 'is provided at the predetermined position by the predetermined depth, the coarse adjustment and the fine adjustment are combined for a short time. The characteristic adjustment is completed.
[0030]
FIG. 10 is a perspective view of a dielectric resonator according to the third embodiment. In the first and second embodiments, the example in which the coupling amount and the resonance frequency are determined for two of the three resonance modes is shown. However, the coupling amount and the resonance frequency are also determined for the second and third resonance modes. In order to perform the adjustment, as shown in FIG. 10, it is only necessary to provide holes on the two outer surfaces of the dielectric resonator 10 that are orthogonal to each other. In the example shown in FIG. 10, the coupling amounts of the TE01δx mode and the TE01δy mode and the respective resonance frequencies are defined by the holes 15 and 15 ′, and the coupling amounts of the TE01δx mode and the TE01δz mode and the respective resonance frequencies are defined by the holes 16 and 16 ′. be able to.
[0031]
FIG. 11 is a top view of a 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 fine adjustment holes 15b and 15b 'are provided in the vicinity of another virtual surface VS1 which is different from the virtual surface VS2 in the vicinity of the rough adjustment holes 15a and 15a'. For example, by providing the holes 15a and 15a ′ on the assumption that the coupling amount of the two resonance modes before providing the hole is 0 (coupling coefficient k = 0%) and the resonance frequencies of the two resonance modes are f1 and f2. If the coupling amount (for example, the coupling coefficient k ′ = 2%) and the resonance frequencies are changed to f1 ′ and f2 ′, respectively, to reduce the coupling amount to a predetermined coupling amount (for example, the coupling coefficient k ″ = 1%), Fine adjustment holes 15b and 15b 'are provided. As a result, the two resonance frequencies are also changed to f1 "and f2". Therefore, in anticipation of the change in the resonance frequency during the fine adjustment, the above f1 "and f2" are provided. The positions and sizes of the fine adjustment holes 15b and 15b ′ may be determined so that the resonance frequency becomes the target resonance frequency and the coupling coefficient k ″ becomes the target coupling coefficient.
[0032]
In addition, by providing each hole in the relationship of the diagonal positions in this way, 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 greatly broken, This has the effect of suppressing the occurrence of spurious mode.
[0033]
Next, a dielectric resonator according to a fifth embodiment will be described with reference to FIGS.
FIG. 12 is a perspective view of a dielectric resonator. In the example of (A), a groove 11 having a predetermined depth is provided so as to extend in parallel to the edge E4 at a position away from the center portion o of a predetermined surface of the dielectric resonator 10. In the example shown in (B), two grooves 11 and 11 'are provided in the same manner.
[0034]
FIG. 13 is a top view showing the positional relationship between the electric field distribution of the two resonance modes to be coupled to the dielectric resonator and the groove. Thus, by providing the grooves 11 and 11 ′ so as to extend in parallel with the ridges at positions away from the center of the predetermined surface, two coupled modes by two resonance modes (TE01δx mode and TE01δy mode) are provided. The two resonance modes are coupled to each other due to a difference in frequency. Further, a difference occurs in the effective dielectric constant at a portion through which the electric field vectors of the two resonance modes to be coupled pass, and a difference occurs in the resonance frequency of the two resonance modes.
[0035]
As shown in FIG. 13C, the positions of the grooves 11 and 11 ′ are represented by distances S and S ′ from the edges E1 and E3. As the distances S and S ′ are reduced, the electric fields of the two coupled modes are reduced. The perturbation to increases and the amount of binding increases. Further, as S and S ′ are increased, the difference in the influence of the two resonance modes on the electric field is increased, and the difference in resonance frequency is increased. Further, the influence on the coupling amount and the resonance frequency difference also changes depending on the ratio of the width and depth of the grooves 11 and 11 '.
[0036]
As described above, both the coupling amount and the difference between the two resonance frequencies change depending on the positions of the grooves 11 and 11 ′, so that the two cannot be determined completely independently, but the width and depth of the grooves 11 and 11 ′ are also adjusted. By doing so, it is possible to determine the resonance frequencies of the two resonance modes and their coupling amounts 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]
Further, if a fine adjustment groove is provided on the surface opposite to 11 ′ as a virtual surface VS1 boundary as indicated by 11 ″, a change in the resonance frequency difference between the two resonance modes can be applied 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 in the vicinity of another orthogonal virtual surface VS2 different from the virtual surface VS1 in the vicinity of the coarse adjustment grooves 11a and 11a ′. By providing the grooves in the diagonal position in this way, 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 greatly broken, and the spurious mode This has the effect of suppressing the occurrence of
[0039]
Next, the configuration of the dielectric filter according to the sixth embodiment will be described with reference to FIG. FIG. 14 shows the positional relationship between the dielectric resonator and the coupling loop coupled thereto in the cavity. The dielectric resonator 10 is the same as the dielectric resonator shown in FIG. In the figure, the cavity is omitted. Each of the coupling loops Ky and Kz has one end connected to the central conductor of the coaxial connector attached to the cavity and the other end connected to the inner surface of the cavity. The coupling loop Ky has its loop surface facing the xz plane. The coupling loop Kz has its loop surface facing the xy plane. Therefore, the coupling loop Ky is magnetically coupled to the TE01δy mode, and the coupling loop Kz is magnetically coupled to the TE01δz mode.
[0040]
As already described with reference to FIG. 10, the TE01δx mode is coupled to the TE01δy mode and simultaneously to the TE01δz mode. There are equivalently three resonators coupled in the order of the resonators. As a result, a filter having a bandpass filter characteristic composed of a three-stage resonator can be configured.
[0041]
Next, the structure of the composite dielectric filter and communication apparatus according to the seventh embodiment is shown in FIG.
Here, the duplexer includes a transmission filter and a reception filter. Both the transmission filter and the reception filter are filters having the above-described configuration. 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 circulate to the reception filter side and the reception signal does not circulate to the transmission filter side. A transmission circuit is connected to the transmission signal input port of the duplexer, and a reception circuit is connected to the reception signal output port. An antenna is connected to the antenna port. Thus, the communication apparatus provided with the dielectric resonator according to the present invention is configured.
[0042]
【The invention's effect】
According to the present invention, the positions are different from the first and second imaginary planes including the two edges of the substantially parallelepiped dielectric resonator, which are parallel and diagonal to each other , and the first By providing a hole at a position different from any of the other two virtual surfaces that bisect the angle formed by the first and second virtual surfaces, including a straight line intersecting the second virtual surface , The two resonance modes can be coupled to each other, and a difference can be made between the resonance frequencies of the two resonance modes.
[0043]
Further, according to the present invention, the groove extending from the center of the outer surface of the dielectric resonator and away from the ridge included in the surface and extending in parallel to the ridge at a predetermined depth is formed. Two resonance modes can be coupled to each other, and a difference can be made between the resonance frequencies of the two resonance modes.
[0044]
Further, according to the present invention, a dielectric filter and a composite dielectric filter having desired filter characteristics can be easily obtained by including the above-described dielectric resonator device and external coupling means coupled externally thereto.
[0045]
In addition, according to the present invention, a small-sized and low-cost communication device can be configured by including the dielectric filter or the composite dielectric filter in a high-frequency circuit unit.
[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 a TE01δx mode electromagnetic field distribution. FIG. 3 is a TE01δy mode electromagnetic field distribution. FIG. 4 is a diagram showing the electromagnetic field distribution of the TE01δz mode. FIG. 5 is a diagram showing the direction of the electric field of the two resonance modes and their coupling modes. FIG. 6 is a perspective view of a dielectric resonator. FIG. 8 is a perspective view of the dielectric resonator according to the second embodiment. FIG. 9 shows the directions of the electric fields of the two resonance modes and their coupling modes. FIG. 10 is a perspective view of a dielectric resonator according to a third embodiment. FIG. 11 shows the positional relationship between electric field distributions and 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 the directions of electric fields of two resonance modes and their coupling modes. FIG. 14 is a perspective view showing the configuration of the main part of a dielectric filter according to a sixth embodiment. FIG. Showing the configuration of the composite dielectric filter and communication device according to the present invention
10-dielectric resonators 11, 11 ', 11a, 11a', 11b, 11b'-grooves 15, 15 ', 15a, 15a', 15b, 15b'-holes VS1, VS2-virtual planes E1, E2, E3 E4-ridge

Claims (5)

In the TE01δ multi-mode dielectric resonator, which is disposed in the cavity in a state separated from the wall surface of the cavity and has a substantially rectangular parallelepiped shape as a whole,
When the position to provide the hole is shown in the positional relationship with the virtual plane,
A first imaginary plane including two ridges in parallel and diagonal positions of the dielectric resonator; and two other ridges in parallel and diagonal positions different from each other. Other than a position that is different from any of the second imaginary planes and includes a straight line intersecting the first and second imaginary planes, and divides the angle formed by the first and second imaginary planes into two equal parts. A dielectric resonator characterized in that a hole is provided at a position different from either of the two virtual planes . In the TE01δ multi-mode dielectric resonator, which is disposed in the cavity in a state separated from the wall surface of the cavity and has a substantially rectangular parallelepiped shape as a whole,
The surface of the dielectric resonator is provided with a groove extending from the central portion of the surface and away from the ridge included in the surface and extending substantially parallel to the ridge at a predetermined depth. A dielectric resonator.   A dielectric filter comprising the dielectric resonator according to claim 1 and external coupling means for external coupling to the dielectric resonator.   A composite dielectric filter comprising a plurality of sets of dielectric filters according to claim 3 and sharing one external coupling means of each dielectric filter.   A communication device comprising the high frequency circuit section comprising the dielectric filter according to claim 3 or the composite dielectric filter according to claim 4.

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