JPS63176002A - Dielectric resonator device - Google Patents

Abstract

PURPOSE:To obtain a dielectric resonator device with an excellent overall characteristic by applying inductive coupling to plural small sized dielectric resonators in axial direction while the shaft of each resonator in common so as to make the asymmetrical mode hardly excited further and improve the heat radiation effect regardless of the small size. CONSTITUTION:A metallic plate 6 standing upright is provided at the middle of the inside of a metallic case and both side faces of the metallic plate 6 and the bottom face of a case member 1 are assembled with plural ceramic bases 7 respectively. A silver electrode is coated to the entire surface of the ceramic base 7 to form an electric wall. Dielectric resonators 52-54 each having a shape of being 1/4 division of the cylindrical resonator are baked and fixed to the silver electrode in contact with the electric wall. The dielectric resonators are contained in the case and subject to inductive coupling in the axial direction while using the axis equivalent to the center shaft of each dielectric resonator in common.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention relates to a small dielectric resonator device (b1 Background of the Invention Dielectric resonators are generally smaller than conventional metal cavity resonators. A resonator having a high Q can be constructed, and a dielectric resonator device used particularly as a bandpass filter is used in a transmink multiplexer and the like in a microwave communication device.

The configuration of the dielectric resonator varies depending on the electromagnetic wave mode used, and the mode is used depending on the purpose. For example, with TE, δ, the spurious characteristics are not very good, but the energy concentration in the resonator is high, and the loss of the entire resonator is determined by the loss of the dielectric resonator alone, so that a high Q can be obtained. In the case of TEM, spurious characteristics are good, but
The loss of the metal conductor is relatively large, and the Q of the resonator is not very high. In the case of TM, the characteristics are intermediate between the above two modes, but since a real current flows through the junction between the dielectric resonator and the case, it is necessary to maintain a good conduction state at this junction. Therefore, it is necessary to absorb the mechanical strain caused by the difference in thermal expansion coefficient between the dielectric resonator made of ceramic and the case, and it is necessary to use metallized ceramic as the material for the case. Therefore, in order to use a workable metal as the case and to increase the Q, a TE61δ mode dielectric resonator is used (C)
2. Description of the Related Art A dielectric resonator using the conventional TE61δ mode is a dielectric resonator in which a cylindrical dielectric resonator made of a Tie-based ceramic material is fixed to a support in a sealed metal case. It is used. As mentioned above, this type of dielectric resonator uses dielectric ceramic, so it can be constructed smaller than a metal cavity resonator, and also because electromagnetic energy is sufficiently concentrated within the dielectric resonator. , it is possible to construct a resonator with high Q! There are signs.

Conventionally, when configuring a bandpass filter by arranging a plurality of such dielectric resonators in the same case, the aforementioned cylindrical dielectric resonators were arranged on a plane inside the metal case and horizontally aligned. Inductively coupled. However, filters based on such arrangement methods are EHIIδ, TMatδ, HEl
, δ and other asymmetric modes are easily excited, and the spurious characteristics are poor.

Therefore, a device in which a plurality of cylindrical dielectric resonators are arranged in the central axis direction, with each dielectric resonator having a common central axis, has also been developed. FIG. 16 is a partially cutaway perspective view showing the structure of the device. In the figure, 21, 22, 23.2
4 represents a cylindrical dielectric resonator, which is fixed in a metal case 30 with a ring-shaped spacer 31 interposed therebetween.

Furthermore, a dielectric resonator device has been developed in which the cylindrical dielectric resonator is made into a fan shape and the symmetry of the electromagnetic wave mode is utilized to miniaturize the entire device and improve heat dissipation. Figure 17 (
Δ), CB) are a top view and a front view showing the internal structure of the device. In the figure, reference numerals 51 to 54 indicate dielectric resonators each having a shape such that a cylindrical dielectric resonator is cut along a plane including its central axis, and the cut surface is in contact with the metal case 40 and is fixed. There is. Note that 43.degree. 45 represents an input/output connector, and 42.44 represents a rond constituting a coupling circuit.

(Problems to be solved by the d+ invention In the conventional dielectric resonator device shown in FIG. 16,
Although the above-mentioned asymmetric mode is hard to be excited and has good spurious characteristics, if synthetic resin is used as the spacer 31, reliability is low in terms of strength, and t
Since an δ is low, there is a problem that the no-load Q0 decreases.

If a ceramic material is used as the spacer, the coefficient of thermal expansion will be significantly different from that of the metal case 30, and it will be difficult to absorb mechanical strain caused by this thermal expansion. Figure 17 (A)
In the dielectric resonator device shown in , CB), each dielectric resonator is brought into contact with the inner wall of the metal case with no gaps between them, so the overall size is reduced and the heat dissipation effect is improved. Similar to conventional dielectric resonator devices in which a plurality of cylindrical dielectric resonators are arranged on a plane, there are problems in that asymmetric modes are easily excited, spurious characteristics are poor, and design is poor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a dielectric resonator device in which the asymmetric mode is less likely to be excited, which is compact, has enhanced heat dissipation effect, and has overall excellent characteristics.

(0) Means for Solving the Problems In the dielectric resonator device of the present invention, electric walls exist on one or two planes including the central axis of electromagnetic field distribution in the mode of use of the dielectric resonator. A plurality of dielectric resonators each having a shape in which one of the dielectric materials sandwiching the electric wall is removed is provided, and an axis equivalent to the central axis of each of these dielectric resonators is shared, and inductive coupling is performed in the direction of this axis. It is characterized by the fact that

(f) Function In the dielectric resonator device of the present invention, since each dielectric resonator has electric walls in one or two planar parts, images of electromagnetic wave modes are generated by these electric walls. , it functions similarly to a conventional cylindrical dielectric resonator, for example. Since each dielectric resonator has its respective axis arranged in common, ET-II, δ, TMo+δ, IIEz
Asymmetric modes such as δ are less likely to be excited, resulting in better spurious characteristics. Furthermore, each small dielectric resonator is smaller than, for example, a conventional cylindrical dielectric resonator;
Alternatively, since the conductor surfaces are in contact with the two plane parts, a dielectric resonator device having a high heat dissipation effect and having a reduced size as a whole is constructed.

(ff) Embodiment FIG. 1 is a partially cutaway perspective view showing the structure of a dielectric resonator device of the present invention. In the figure 1. Reference numeral 2 denotes a case member that constitutes a box-shaped case by combining these two parts, and is made of a metal material such as iron or aluminum alloy. On the side of the case member 1 are N-type connectors 3.4 for input and output.
is installed. An upright metal plate 6 is provided in the center of the metal case. A plurality of ceramic substrates 7 are installed on both sides of the metal plate 60 and on the bottom surface of the case member 1, respectively. The entire surface of the ceramic substrate 7 is covered with a silver electrode to form an electric wall. In contact with this electric wall, a dielectric resonator in the shape of a cylindrical dielectric resonator divided into four parts is baked and fixed to the silver electrode.

These dielectric resonators 51 to 58 (only 52 to 54 are shown in the figure) are housed in a case.

FIG. 2 is a partial sectional view of the device shown in FIG. 1, showing a part of the cross section of a plane parallel to the end faces on which the connectors 3 and 4 are formed. In the figure, 52 represents one dielectric resonator, one outer plane 52a including the central axis is in contact with the vertical surface of the ceramic substrate 7, and the other outer plane 52a is in contact with the vertical surface of the ceramic substrate 7.
b is fixed in contact with the horizontal surface of the ceramic substrate 7. The inner wall 2a of the case member 2 is formed into a cylindrical surface centered on the central axis of the dielectric resonator. Note that this cylindrical surface 2
a is formed to facilitate characteristic calculation, and does not necessarily have to have such a shape. In the figure, reference numeral 8 denotes a frequency tuning adjustment screw, which is made of metal or dielectric material and is screwed into a screw hole provided in a corner of the case member 2 as shown in the figure. By doing so, the tip portion 8a
is protruded into the case, and frequency tuning adjustment is performed depending on the amount of protrusion.

The resonator system shown in FIG. 2 is used in the T E a rδ mode. At that time, a displacement current flows in the dielectric resonator in the direction shown by the broken line in the figure, and 1! formed on the surface of the ceramic substrate 7. A main real current 11 flows through the joint between the electrodes 7a, 7b and the outer plane of the dielectric resonator, and a leakage current 10 of the real current flows through the inner wall 2a of the case member 2. In other words, the path through which the resonant current flows strongly is free of any places where the smooth flow of current is likely to be hindered, such as the joint surface between the case body and the lid in a metal case, and an integrated electrode is provided. It is being On the other hand, since the resonance current flowing through the case is a leakage current, a metal case made by combining two case members can be used. The metal case is suitable for mass production, and this structure has high industrial value. Further, at this time, the dielectric resonator 52 and the like generate heat due to dielectric loss and Joule I member of the surrounding conductor, but the heat is radiated from the case members 1 and 2 via the ceramic substrate 7 and the metal plate 6. Therefore, the heat is easily radiated to the outside and can be used even in high power circuits. Note that at this time, since the dielectric resonator 52 and the like are fixed to the case member via the ceramic substrate 7, the difference in thermal expansion between the case member made of a metal material and the dielectric resonator made of a ceramic material. It is possible to absorb the mechanical strain caused by this, and the bond between the silver electrode on the surface of the ceramic substrate, which acts as an electric wall, and the dielectric resonator will not peel off (and it is possible to maintain complete TEelδ mode excitation. Note that each ceramic substrate 7 may be integrated into a single substrate.Furthermore, each silver electrode 7a, 7b may also be configured as one continuous electrode.

FIG. 3 shows a partial cross section in a direction perpendicular to the side surface of the case member to which the connector 3 is attached in FIG. In the figure, 51 is a first stage dielectric resonator, 9 is a strip line substrate, and 10 is a lead wire connecting the input connector 3 and this strip line 9. FIG. 4 is a perspective view showing this part. As shown in the figure, the strip line 9 is composed of a strip substrate 9a and a strip conductor 9b, and the lead wire 1
0 is the center conductor of the input connector 3 and the strip conductor 9b
connecting between. A silver electrode is formed on the bottom surface of the dielectric resonator 51 at the first stage entrance, and the four strips 9b
It is connected with direct current. In this way, the dielectric resonator and the input connector are electrically connected. 5 and 6 are dielectric resonators 5 shown in FIGS. 3 and 4.
1 represents an equivalent circuit of the electrodes formed on each plane of FIG. 1 and the engagement circuit of this input section. The electrode 51a formed on the vertical plane in FIG. 5 corresponds to the coil in FIG. 6, and the capacitance between the electrodes 51a and 51b in FIG.
and 51c correspond to capacitors C1 and C2 in FIG. 6, respectively. Note that the resistance R represents the impedance of the load connected to the connector 3. The input impedance is set by the size and shape of the electrode formed on the horizontal surface of the first stage dielectric resonator, and matched with the impedance of the coaxial cable connected to the input connector 3.

Although the examples shown in FIGS. 3 to 6 concern the coupling circuit on the input section, a similar circuit is also configured on the output side.

FIG. 7 is a view showing a part of a cross section parallel to the bottom or top surface of the device shown in FIG. In the figure, 53 to 56 represent third to sixth stage dielectric resonators. Also,
Sl is an opening for coupling the fourth stage dielectric resonator 54 and the fifth stage dielectric resonator 55, and S2 is the third stage dielectric resonator 53 and the sixth stage dielectric resonator 55. This represents a slot for coupling with the dielectric resonator 5G. As described above, each of these dielectric resonators is used in the T E o Iδ mode, but at the same time, the second harmonic mode is also excited. The generation of this second harmonic wave is one of the causes of deterioration of spurious characteristics. In this embodiment, this double wave coupling is removed in the coupling between the fourth stage dielectric resonator 54 and the fifth stage dielectric resonator 55. That is, in the figure, Hl represents the magnetic field line of the second harmonic that can be generated in the dielectric resonator 54, and H2 represents the magnetic field line of the second harmonic that can be generated in the dielectric resonator 55. By arranging these two dielectric resonators in a positional relationship such that the magnetic field vectors of the second harmonics of the body resonators are orthogonal to each other as integral values, the coupling of the second harmonics can be canceled.

In addition, according to this example, since a quarter-shaped dielectric resonator is used, the aforementioned asymmetric mode itself is not excited, and as a result, spurious characteristics are improved compared to a conventional cylindrical dielectric resonator. do. In cases other than the quadrant shape, a slightly asymmetrical mode occurs, but the E mode cannot exist, so that spurious characteristics are still better than those shown in FIG. 16.

Furthermore, due to the presence of the slot I-32 in FIG. 7, the third stage dielectric resonator 53 and the sixth stage dielectric resonator 5
6 is weakly coupled. As a result, an attenuation pole is generated due to the characteristics of the bandpass filter, thereby improving the filter characteristics.

As described above, a bandpass filter using eight stages of dielectric resonators is constructed. FIG. 8 shows its equivalent circuit. In the figure, Qel represents the coupling portion between the connector 3 and the first stage dielectric resonator 51, and Qe2 represents the coupling portion between the eighth stage dielectric resonator (58) and the connector 4.

Also, k12. 23. 34. 45. 56, 6
7, 78 represent coupling portions between the dielectric resonators of the number of stages indicated by these two-finger numbers. Further, 36 represents a coupling portion between the third stage dielectric resonator 53 and the sixth stage dielectric resonator 56 due to the presence of the slot S2 shown in FIGS. 1 and 7.

Specific examples of the constituent materials and dimensions of the bandpass filter shown above, and characteristic examples under those conditions are shown below.

FIG. 9 shows each resonator and the material of the ceramic substrate holding these resonators. Further, FIG. 11 shows the coupling coefficient between dielectric resonators in terms of the dimensions and positional relationships of each dielectric resonator.

Figures 12 and 13 are diagrams showing the characteristics of a bandpass filter configured under these conditions. Figure 12 shows the return loss and attenuation with respect to frequency, and Figure 13 shows the characteristics of the bandpass filter with respect to frequency. Represents insertion loss. Furthermore, the 10th
The figure shows the specifications of this bandpass filter. In this way, a bandpass filter with low insertion loss and large attenuation can be constructed.

In the above embodiment, the input and output portions are coupled by capacitive coupling, but it is also possible to use inductive coupling. FIGS. 14(A) to 14(C) show examples of such cases. The example shown in FIG. 3A is an example in which a metal rod 11 is protruded along the inside of the case from a connector 3 attached to the side surface of the case, and the lines of magnetic force generated by this metal rod 11 interlink with the dielectric resonator 51. do. In the example shown in FIG. 6(B), a loop 12 made of metal wire is formed inside the case.
One end 12a thereof is electrically connected to the case by soldering or the like, and the other end is connected to a connector 3 formed on the upper surface of the case. In the example shown in FIG. 3C, a metal wire 13 is provided along the inner wall of the case and the dielectric resonator, one end 13a of which is connected inside the case, and the other end connected to a connector 3.
It is connected to the. In this way, the metal rod or money wire and the dielectric resonator are inductively coupled.

Further, in the above embodiment, when fixing the dielectric resonator in contact with the inner wall of the case, a ceramic substrate with silver electrodes formed on the surface was used, but for example, as shown in FIG. It is also possible to fix with an elastic body made of a metal material. In the figure, the workpiece 4 is a corrugated metal plate or metal net, which is partially adhered by soldering or fixed using a synthetic resin adhesive such as epoxy. By fixing through the elastic body in this manner, it is possible to absorb mechanical strain due to the difference between the thermal expansion of the dielectric resonator made of a ceramic material and the thermal expansion of the case member made of a metal material.

Further, in the above embodiment, a dielectric resonator with a diencephalic angle of 906 degrees is used, but a dielectric resonator with a diencephalic angle of smaller than 30 degrees, for example, may be used. However, in this case, if the diencephalon angle is made too small, the no-load loss increases and the no-load Q decreases. On the other hand, if the angle is large, for example 180'', the size cannot be reduced much, but the heat dissipation effect is better than that of a conventional dielectric resonator as shown in FIG.

Q+) Effects of the Invention As described above, according to the present invention, a plurality of small dielectric resonators are inductively coupled in the axial direction by making the axis of each resonator common, which eliminates the conventional coupling in the central axis direction. Similar to the dielectric resonator device, it is possible to construct a filter that has high designability, is less likely to excite asymmetric modes (and has excellent spurious characteristics).

Moreover, the external dimensions of each dielectric resonator itself are small, and the internal dimensions of the case can also be made small, so the entire dielectric resonator device can be downsized. Furthermore, since each dielectric resonator is in direct contact with the inner wall of the case, it has a high heat dissipation effect and can be used in high-power circuits.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing the structure of a dielectric resonator device according to an embodiment of the present invention, FIG. 2 is a partially sectional view of the same device, and FIG. 3 is a dielectric resonator shown in FIG. 1. 4 is a perspective view of the portion shown in FIG. 3, FIGS. 5 and 6 are diagrams showing the structure and equivalent circuit of the first stage dielectric 41III device, and FIG. The figure is a partial sectional view of the dielectric resonator device shown in FIG. 1, FIG. 8 is an equivalent circuit of the dielectric resonator device, and FIG. 9 is a diagram showing the materials of the resonator and ceramic substrate constituting the device. Figure 10 is a diagram representing the characteristics obtained as a specific bandpass filter, Figure 11 is a diagram representing the coupling coefficient between each dielectric resonator, and Figures 12 and 13 are diagrams representing the band pass filter. It is a figure showing the characteristic as a pass filter. FIGS. 14(A) to 14(C) are diagrams representing input/output coupling circuits in a dielectric resonator device according to another embodiment,
FIG. 15 is a sectional view showing a fixing structure of a dielectric resonator according to still another embodiment, FIG. 16, FIG. 17 (Δ), (B)
1 is a diagram showing the structure of a conventional dielectric resonator device. 1, 2-case member, 3, 4-connector, 51-58-
Dielectric resonator, 6-metal plate, 7-ceramic substrate.

Claims (1)

[Claims] (1) An electric wall exists on one or two planes including the central axis of electromagnetic field distribution in the usage mode of the dielectric resonator,
A plurality of dielectric resonators each having a shape in which one of the dielectric materials sandwiching the electrical wall is removed are provided, and a common axis equivalent to the central axis of each of these dielectric resonators is provided, and the guidance is guided in the direction of this axis. A dielectric resonator device characterized by being coupled.