JP2003101315A - High-frequency circuit element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-frequency circuit element that is simple in constitution, small in size, and low in loss in a high-frequency region, such as the milliwave band, etc. SOLUTION: This high-frequency circuit element uses a TM mode resonator containing a dielectric porcelain expressed by the compositional formula of xBaO-yMgO-zTaO5/2 (wherein, x+y+z=1, 0.496<=x<=0.506, 0.150<=y<=0.168, and 0.336<=z<=0.350), a shielded conductor 2 surrounding the porcelain, and input-output lines 4a and 4b composed of strip lines. The dielectric porcelain is fixed by means of a supporting member in the shielded conductor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator used in a device for handling high frequency signals such as a wireless communication system and a circuit element such as a dielectric filter including the resonator. Specifically, FWA (Fixed Wireless Acces) using millimeter wave or microwave
s) It can be applied to the high frequency circuit part in the transceiver of the system, the high frequency circuit part of the terminal and the base station of the mobile communication (cell phone) system, the circuit handling the high frequency modulated signal in the optical communication system, etc. is there.

[0002]

2. Description of the Related Art In recent years, high-frequency circuit elements (high-frequency filters, etc.) constructed using resonators have been widely used.
Among them, the dielectric resonator is very useful because a small-sized and low-loss (high Q) resonant circuit can be realized by using a ceramic material having a high dielectric constant and low loss.

In order to configure such a resonator and a circuit element other than the resonator (for example, an amplifier circuit, a transmission circuit, a mixer circuit, etc.) on the same substrate and to make a high frequency circuit into a module, It is necessary to input / output a signal to / from the resonator via the strip line. A high frequency circuit using such a dielectric resonator is disclosed in Japanese Patent Laid-Open No. 10-284.
As disclosed in Japanese Patent No. 946, there is one in which a dielectric resonator is arranged on a circuit board and a strip line is arranged in the vicinity thereof to perform input / output to / from the resonator.

In this case, resonance in the TE _01d mode in the circular cross-section resonator is carried out for the purpose of transmitting only a desired frequency component or removing an unnecessary frequency component from the high frequency signal from the strip line. _Used TE _01d
A mode dielectric resonator is used.

[0005]

However, in such a structure in which the dielectric resonator is arranged on the substrate, since the surroundings of the resonator are used without being shielded, the electromagnetic wave is radiated from the dielectric resonator. At the same time, the loss of the resonator increases (Q value decreases). Further, the radiated electromagnetic waves may be coupled with other circuits on the substrate, and the operation of the circuits may become unstable. Furthermore, in order to suppress the coupling between the radiated electromagnetic wave and other circuits, it is necessary to keep the dielectric resonator away from other circuits,
This is a factor that prevents the miniaturization of the entire circuit. these,
The problem caused by the radiation of electromagnetic waves from the dielectric resonator becomes more serious as the frequency increases, and thus becomes a fatal problem in the millimeter wave band and the like.

Further, since the loss of the ceramic material used for the dielectric resonator increases as the resonance frequency becomes higher, it is necessary to use a ceramic material having a remarkably low loss particularly in the millimeter wave band.

In view of the above problems, it is an object of the present invention to provide a high frequency circuit element using a dielectric ceramic having excellent dielectric characteristics in a high frequency region.

[0008]

In order to solve the above-mentioned problems, the first structure of the high-frequency circuit element according to the present invention has a composition formula xBaO-yMgO-zTaO _5/2 (x, y and z
Respectively, x + y + z = 1, 0.496 ≦ x ≦ 0.
506, 0.150 ≦ y ≦ 0.168, 0.336 ≦ z
A dielectric porcelain represented by ≦ 0.350), a shield conductor surrounding the dielectric porcelain, and an input / output line consisting of a strip line, and the dielectric porcelain is supported inside the shield conductor. TM fixed by members
It is characterized by being configured using a mode resonator.

The second aspect of the high-frequency circuit element according to the present invention
Has the composition formula xBaO-yCoO-zTaO.
_5/2 (x, y and z are respectively x + y + z = 1,
0.498 ≦ x ≦ 0.504, 0.158 ≦ y ≦ 0.1
67, 0.329 ≦ z ≦ 0.344), a dielectric ceramic, a shield conductor surrounding the dielectric ceramic, and an input / output line formed of a strip line,
The dielectric porcelain is configured by using a TM mode resonator fixed inside the shield conductor with a support member.

Furthermore, the third aspect of the high-frequency circuit element according to the present invention
The configuration includes any one of the dielectric porcelain, a shield conductor surrounding the dielectric porcelain, and an input / output line formed of a strip line, and the dielectric porcelain is fixed on the dielectric substrate inside the shield conductor. It is characterized in that it is configured by using the TM mode resonator that is used.

A fourth aspect of the high-frequency circuit element according to the present invention
In the above configuration, a plurality of dielectric resonators are used.

According to the configuration of the high frequency circuit element of the present invention,
Since there is no emission of electromagnetic waves from the dielectric resonator, the loss is significantly lower than that of the conventional structure (high Q value), and by using the dielectric ceramic with low loss even in a high frequency band, the loss is remarkably low. A high frequency circuit element can be realized. Further, since there is no interference with other circuits, the size of the entire circuit can be reduced. Furthermore, by arranging the input / output strip lines on the circuit board, it becomes easy to apply to a high frequency circuit having a module structure.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A high frequency circuit element according to the present invention will be described below.

FIG. 1 shows an example of a high-frequency circuit element according to the present invention. FIG. 1 (a) is a perspective view, FIG. 1 (b) is a sectional view seen from the side, and (c) is a sectional view seen from above. It is a figure.

A rectangular parallelepiped dielectric resonator 1 made of a dielectric ceramic is fixed in a shield conductor 2 by a support member 3. In the example of FIG. 1, the space between the dielectric resonator 1 and the shield conductor 2 is filled with the support member 3. Input / output lines 4 a and 4 b formed of microstrip lines are inserted into the shield conductor 2 from the front and the rear of the shield conductor 2. Here, a window is opened in a part of the outer wall of the shield conductor 2, the input / output lines 4a and 4b are inserted, and the upper surfaces of the input / output lines 4a and 4b are covered with the insulators 7a and 7b. The insulators 7a and 7b are the input / output line boards 6a and 6b.
This is to prevent the upper strip conductors 5a and 5b from short-circuiting to the shield conductor 2.

The shield conductor 2 and the ground conductor portion 9 serve as a ground plane for the input / output lines 4a and 4b. Therefore,
When connecting to the external circuit, a signal voltage may be applied between the strip conductor 5a (or 5b) and the ground conductor portion 9. In this configuration, by appropriately setting the shapes and characteristics of the dielectric resonator 1, the shield conductor 2, and the support member 3, the dielectric resonator 1 resonates in a resonance mode called TM _11d mode in a rectangular cross section resonator. This makes it possible to realize a TM _11d mode resonator with the configuration shown in FIG. The configuration of FIG. 1 has a function as a resonator and can be used as a one-stage bandpass filter.

The TM _11d mode in the rectangular section resonator is TM _01d in the circular section resonator using the cylindrical dielectric.
It is equivalent to the mode. This is the mode designation,
How to decide the first two subscripts (11 or 01)
The rectangular cross-section resonator is based on the periodicity of the electromagnetic field in each side of the rectangle of the cross section, whereas the circular cross-section resonator is based on the periodicity of the electromagnetic field in the circumferential and radial directions of the circle of the cross section. Because it is based.

[0018]

EXAMPLES The present invention will be described in more detail below with reference to examples.

(Example 1) First, a method for manufacturing a dielectric ceramic will be described.

As starting materials, BaCO ₃ , MgO, T
Using a ₂ O ₅ , weigh these so that they have the desired composition,
Wet mixed with ethanol using a ball mill.
The volume ratio of powder to ethanol was about 2: 3. The mixture was taken out of the ball mill, dried at 110 ° C., and then calcined in air at a temperature of 1000 ° C. for 2 hours. The calcined product was wet-ground in the above ball mill together with ethanol. The crushed sludge was taken out from the ball mill and dried, and then 8% by weight of a 6% concentration polyvinyl alcohol solution was added as a binder to the powder, and the mixture was homogenized and sized through a 32 mesh sieve. The sized powder uses a mold and a hydraulic press, and the molding pressure is 100 MPa.
It was molded in. The shape of the molded body is 20 mm in diameter and about 3 in thickness.
The columnar shape is mm. This molded product was placed in a high-purity magnesia pod and held in air at a temperature of 600 ° C for 10 hours to perform binder out, and then held in air at a temperature of 1500 to 1700 ° C for 4 to 96 hours. And fired to obtain a dielectric ceramic. The obtained cylindrical dielectric porcelain was polished to a thickness of 1 mm, and the size was about 1 ×.
It was cut into a 1 × 5 mm square column.

Next, the TM _11d constructed as shown in FIG.
The mode dielectric resonator will be described.

The dielectric resonator 1 (rectangular prismatic dielectric ceramic) was fixed in a shield conductor 2 made of brass whose inner wall was plated with gold. The size of the inner wall of the shield conductor 2 is 2 × 2 × 10 mm.
Further, Teflon resin was used as the support member 3 to fill the gap between the shield conductor 2 and the dielectric resonator 1. I / O line 4
a and 4b are input / output line boards 6 made of Teflon resin.
Silver ribbon on top of a and 6b (thickness: 0.1 mm,
The strip conductors 5a and 5b each having a width of about 1 mm) are mounted on the strip conductors. Further, the strip conductors 5a and 5b are extended to the inside of the shield conductor 2 to form coupling probe portions 8a and 8b.

FIG. 2 shows an example of transmission characteristics measured by a network analyzer. By analyzing the electromagnetic field distribution, it was confirmed that there is a fundamental resonance mode at about 26 GHz and this mode is the TM _11d mode. From this, it was confirmed that this element operates as a resonance circuit.

Composition of the produced dielectric porcelain and TM _11d
The unloaded Q value of the mode dielectric resonator is shown in (Table 1). The samples marked with * in Table 1 are comparative examples.

[0025]

[Table 1]

As shown in (Table 1), in samples other than the examples marked with *, a high Q value of 850 or more could be obtained. Further, x, y and z are respectively x + y + z =
1, 0.500 ≦ x ≦ 0.504, 0.153 ≦ y ≦
In the sample having the range of 0.164, 0.336 ≦ z ≦ 0.347, a particularly high Q value of 1100 or more could be obtained.

1 / by normal microstrip line
Since the Q value of the two-wavelength resonator is about 100, it has been experimentally shown that a very low loss resonance circuit can be constructed by using the TM mode dielectric resonator of the present invention.

In this embodiment, Teflon (registered trademark) resin is used as the supporting member 3 to fill the gap between the shield conductor 2 and the dielectric resonator 1. However, as the supporting member, a dielectric substrate such as alumina is used. By integrating the dielectric substrate with the input / output line substrates 6a and 6b by using, the structure can be simplified and the high frequency circuit device can be easily manufactured. Actually, the dielectric resonator 1 having the same composition as sample No. 9
Was fixed on a single alumina substrate, and strip conductors 5a and 5b were placed on the same substrate to fabricate a TM mode dielectric resonator. As a result, a high Q value equivalent to that of sample No. 9 was obtained. It was

Further, although the present embodiment has one dielectric resonator 1 and can be used as a one-stage bandpass filter, a plurality of dielectric resonators 1 are provided in the shield conductor 2.
By arranging, it is possible to configure a multi-stage bandpass filter and realize desired filter characteristics. actually,
A three-stage bandpass filter was manufactured using a dielectric ceramic having the same composition as sample No. 9, and compared with a three-stage bandpass filter using a 1 / 2-wavelength resonator using a normal microstrip line, An insertion loss of 1/5 could be realized.

(Example 2) BaCO ₃ , CoO, and Ta ₂ O ₅ were used as starting materials for the dielectric ceramic, and the dielectric resonator 1 (rectangular prismatic dielectric ceramic) was used in the same manner as in Example 1. Got

Composition of the produced dielectric ceramics and FIG.
No-load Q of TM _11d mode dielectric resonator with the configuration shown in
The values are shown in (Table 2). Samples marked with * in (Table 2) are comparative examples.

[0032]

[Table 2]

As shown in (Table 2), samples other than the examples marked with * were able to obtain a high Q value of 780 or more. Further, x, y and z are respectively x + y + z =
1, 0.498 ≦ x ≦ 0.502, 0.160 ≦ y ≦
In the sample having the range of 0.166, 0.332 ≦ z ≦ 0.342, a particularly high Q value of 980 or more could be obtained.

1 / by normal microstrip line
Since the Q value of the two-wavelength resonator is about 100, it has been experimentally shown that a very low loss resonance circuit can be constructed by using the TM _11d mode dielectric resonator of the present invention.

In this embodiment, Teflon resin is used as the support member 3 to fill the gap between the shield conductor 2 and the dielectric resonator 1. However, a dielectric substrate such as alumina is used as the support member, Dielectric board and I / O line board 6a
By integrating 6 and 6b, the structure can be simplified and the high-frequency circuit element can be easily manufactured. Actually, the dielectric resonator 1 having the same composition as the sample No. 17 is set to 1
When a TM mode dielectric resonator was manufactured by fixing the conductors on a single alumina substrate and arranging the strip conductors 5a and 5b on the same substrate, a high Q value equivalent to that of Sample No. 17 could be obtained.

Furthermore, this embodiment is a case where there is one dielectric resonator 1 and it can be used as a one-stage bandpass filter, but a plurality of dielectric resonators 1 are provided in the shield conductor 2.
By arranging, it is possible to configure a multi-stage bandpass filter and realize desired filter characteristics. actually,
A three-stage bandpass filter was manufactured using a dielectric ceramic having the same composition as sample No. 17, and compared with a three-stage bandpass filter using a half-wave resonator using a normal microstrip line, An insertion loss of 1/5 could be realized.

[0037]

As described above, by using the structure of the high-frequency circuit device of the present invention, it is possible to realize a small-sized and low-loss high-frequency circuit device with a simple structure. In particular, the effect is more exerted by applying to circuit elements such as resonators and filters in the millimeter wave band.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a high frequency circuit element according to the present invention.

FIG. 2 is a diagram showing an embodiment of a high-frequency circuit element according to the present invention.

FIG. 3 is a diagram showing an embodiment of a high-frequency circuit device according to the present invention.

FIG. 4 is a diagram showing frequency characteristics in one embodiment of the high-frequency circuit device according to the present invention.

[Explanation of symbols]

1 Dielectric resonator 2 shield conductor 3 Support members 4a, 4b input / output line 5a, 5b Strip conductor 6a, 6b I / O line board 7a, 7b insulator 8a, 8b binding probe part 9 Ground conductor

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G030 AA07 AA10 AA21 BA09                 5G303 AA02 AB10 BA12 CA01 CB03                       CB09 CB17 CB33 CD01 CD04                       DA05                 5J006 HC03 HC07 HC13 HC21 HC24                       JA01 LA02 LA13 LA21 NA08                       PA01 PA03 PA04 PB04

Claims (8)

[Claims] 1. A composition formula xBaO-yMgO-zTaO.
_5/2 (x, y and z are respectively x + y + z = 1,
0.496 ≦ x ≦ 0.506, 0.150 ≦ y ≦ 0.1
68, 0.336 ≦ z ≦ 0.350), a dielectric porcelain, a shield conductor surrounding the dielectric porcelain, and an input / output line formed of a strip line,
A high-frequency circuit element in which the dielectric porcelain is constituted by using a TM mode resonator in which a supporting member is fixed inside the shield conductor. 2. A composition formula xBaO-yMgO-zTaO.
_5/2 (x, y and z are respectively x + y + z = 1,
0.500 ≦ x ≦ 0.504, 0.153 ≦ y ≦ 0.1
64, 0.336 ≤ z ≤ 0.347), a dielectric porcelain, a shield conductor surrounding the dielectric porcelain, and an input / output line formed of a strip line,
A high-frequency circuit element in which the dielectric porcelain is constituted by using a TM mode resonator in which a supporting member is fixed inside the shield conductor. 3. The high-frequency circuit element according to claim 1, wherein the dielectric ceramic is fixed on the dielectric substrate inside the shield conductor. 4. The high frequency circuit element according to claim 1, wherein the high frequency circuit element is composed of a plurality of dielectrics. 5. The composition formula xBaO-yCoO-zTaO.
_5/2 (x, y and z are respectively x + y + z = 1,
0.498 ≦ x ≦ 0.504, 0.158 ≦ y ≦ 0.1
67, 0.329 ≦ z ≦ 0.344), a dielectric ceramic, a shield conductor surrounding the dielectric ceramic, and an input / output line formed of a strip line,
A high-frequency circuit element in which the dielectric porcelain is constituted by using a TM mode resonator in which a supporting member is fixed inside the shield conductor. 6. A composition formula xBaO-yCoO-zTaO.
_5/2 (x, y and z are respectively x + y + z = 1,
0.498 ≦ x ≦ 0.502, 0.160 ≦ y ≦ 0.1
66, a numerical value represented by 0.332 ≦ z ≦ 0.342), a shield conductor surrounding the dielectric ceramic, and an input / output line formed of a strip line,
A high-frequency circuit element in which the dielectric porcelain is constituted by using a TM mode resonator in which a supporting member is fixed inside the shield conductor. 7. The high frequency circuit element according to claim 5, wherein the dielectric ceramic is fixed on the dielectric substrate inside the shield conductor. 8. The high-frequency circuit element according to claim 5, which is composed of a plurality of dielectrics.