GB2342784A

GB2342784A - Dielectric resonators with embedded adjustment means

Info

Publication number: GB2342784A
Application number: GB9927566A
Authority: GB
Inventors: Yutaka Ida; Kiyoshi Kanagawa
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 1998-04-23
Filing date: 1999-04-21
Publication date: 2000-04-19
Anticipated expiration: 2019-04-21
Also published as: GB2342784B; GB9927566D0

Abstract

A dielectric resonator comprises a dielectric plate 3 with electrodes 1 on both main sides, with circular openings 4a, 4b in the electrodes which form resonator sections. The characteristics of the resonator may be changed by embedding parts 22a-c with a different dielectric constant to the plate within it. These parts may be placed in the resonator sections to adjust resonant frequency of the section. Additionally, parts may be positioned between adjacent resonator sections to adjust the coupling factor between them. Embedded parts 22 may comprise air, and may extend through the plate (see figure 5B). The resonator may be used in constructing dielectric filters, oscillators, sharing devices and other communication devices.

Description

DIELECTRIC RESONATOR DEVICE, DIELECTRIC FILTER, OSCILLATOR, SHARING DEVICE, AND ELECTRIC APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric resonator such as a dielectric filter for use in the microwave band or millimeter wave band, an oscillator, a sharing device, and a communication device each including the dielectric resonator.

2. Description of the Related Art In order to realize advanced mobile communication services and multi-media communication services, it is necessary to transmit a high capacitance information at an ultra high speed. For this purpose, the millimeter wave band having a wide band width is suitable. As new uses utilizing effectively the characteristics of the millimeter wave band, in addition to the uses of communication, a motorcar radar for absorbing collision energy is exemplified. It is much expected that the millimeter wave radar serves the assurance of safety required particularly when it mists or snows, for which a conventional laser radar utilizing light is ineffective.

If a conventional circuit configuration formed mainly of microstrip lines is used in the millimeter wave band, Q is reduced with the loss increased. Further, as regards a TEO, dielectric resonator, used widely conventionally, a great amount of resonant energy is leaked on the outside of the resonator. For this reason, in the case of the resonator and the circuit used in the millimeter wave band and having a small relative size, there is the problem that lines are undesirably coupled to each other, and the design and the reproducibility of the characteristics become difficult.

To solve this problem, the inventors have devised PDIC Tm (Planer Dielectric Integrated Circuit), and proposed a millimeter wave band module using this technique.

An example of the planar circuit type dielectric resonator incorporated in the module is disclosed in Japanese Unexamined Patent Publication No. 8-265015.

FIG. 9 shows the configuration of the dielectric resonator device. In FIG. 9, there is shown a dielectric plate 3, and on the opposite main faces of the dielectric plate 3, electrodes are formed with electrode sections which are circular, have a predetermined size, and are opposite corresponding sections on the other face of dielectric plate 3, and the upper electrode of the dielectric plate 3 is shown at a numeral 1 and the electrode sections at numerals 4a and 4b. With this configuration, the section of the dielectric resonator device, sandwiched between the electrode sections, is used as the dielectric resonator section.

In a device employing the planar circuit dielectric resonator as shown in FIG.

9, metallic adjusting screws are provided for a shield case 24 in such a manner that the insertion amount of the screws in the shield case can be adjusted. With the adjusting screws, the resonant frequency of the dielectric resonator sections and the coupling factor between the adjacent dielectric resonator sections can be adjusted.

However, in the case of the metallic adjusting screws used, an insertion loss is produced in the adjusting screws with the unloading Q reduced, when the adjusting screws are near to the resonator sections. For this reason, there is the problem that when the dielectric resonator device is used as a filter, its filter characteristics are deteriorated. Further, there is caused the problem that the outside size of the device is large since the adjusting screws are partially projected to be on the outside of the shield case.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a dielectric resonator device of which the characteristics can be adjusted without its unloading Q reduced.

It is another object of the present invention to provide a transmissionreception sharing device and a communication device each including the dielectric resonator device, which are small in size, and have excellent characteristics.

According to the present invention, there is provided a dielectric resonator device comprising electrodes formed on the opposite main faces of a dielectric plate, said electrodes having at least one pair of electrode non-formation sections opposite to each other and having substantially the same shape and size, in which a portion of the dielectric plate sandwiched between said electrod non-formation sections opposite to each other acts as a dielectric resonator section, wherein a part having a different dielectric constant from said dielectric plate is provided inside the dielectric plate in said dielectric resonator section or inside the dielectric plate between adjacent dielectric resonator sections.

In this way the resonant frequency of the resonator section, the coupling factor between the adjacent dielectric resonator sections, the external Q factor, and the spurious characteristic are adjusted.

A dielectric filter may be formed of a signal input-output means for inputting or outputting a signal, provided in the dielectric resonator section. The resonant frequency of the resonator section, the coupling factor between the adjacent dielectric resonator sections, the external Q factor, and the spurious characteristic are determined by the attachment position, the dielectric constant, the size, and the shape of the dielectric chip. Thus, the dielectric filter having characteristics predetermined as described above may be formed.

Further, an oscillator may be formed of a negative characteristic resistance circuit connected to the coupling line coupled to the dielectric resonator section. As described above, the resonant frequency of the resonator section, the coupling factor between the adjacent dielectric resonator sections, the external Q factor, and the spurious characteristic are determined by the attachment position, the dielectric constant, the size, and the shape of the dielectric chip attached to the dielectric plate, or by the size and shape of a portion of the dielectric plate having a different dielectric constant. Thus, the oscillator having characteristics predetermined as described above may be formed.

According to the present invention, a sharing device may be formed of at least one of the signal input-output means being connected to a plurality of the dielectric resonator sections. For example. a duplexer provided with a transmitting filter and a receiving filter, and a mutiplexer provided with at least three filters may be formed.

Thus, the sharing device with a lower insertion loss and excellent branching characteristics can be attained.

Further, an electronic apparatus such as a communication device or the like may be formed, including in its high frequency circuit section one of the dielectric resonator device, the dielectric filter, and the sharing device. Thus, the electronic apparatus having the high frequency circuit with low loss and spurious characteristic can be attained.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1 B are illustrations of an example of that dielectric pieces are buried in the dielectric resonator sections; FIG. 2A consists of two illustrations of the position of the buried dielectric piece in the dielectric resonator section; FIGS. 2B and 2C are graphs showing the relationship of the frequency difference between the basic mode and the spurious mode to the dielectric constant of the dielectric piece; FIG. 3A consists of two illustrations of the position of the dielectric piece buried in the dielectric resonator section; FIGS. 3B and 3C are graphs showing the relationship of the frequency difference between the basic mode and the spurious mode to the dielectric constant of the dielectric piece; FIGS. 4A and 4B are illustrations of another example that the buried dielectric pieces are in the dielectric resonator sections; FIGS. 5A and 5B are illustrations of a sill further example of that the buried dielectric pieces are in the dielectric resonator sections; FIGS. 6A and 6B are illustrations of an example that digging portions are formed in the dielectric resonator sections; FIGS. 7A and 7B are illustrations of another example of that digging portions are formed in the dielectric resonator sections; FIGS. 8A and 8B are illustrations of an example of that perforations are formed in the dielectric resonator sections; FIG. 9 is an illustration of an example of the configuration of a conventional dielectric filter.

The arrangement of the dielectric resonator device of an embodiment will be described with reference to FIGS. 1 through 3.

In this second embodiment, a dielectric piece having a different dielectric constant from the dielectric plate 3 is buried in the dielectric plate. FIG. 1A is a plan view of the dielectric plate, and FIG. 1B is a cross-sectional view thereof. In this example, a dielectric piece 22a is buried inside of the electrode non-formation section 4a, and the dielectric pieces 22b and 22c inside of the electrode non-formation section 4b, respectively.

FIG. 2A and FIG. 3A show the positions of the buried dielectric piece, and FIG. 2B and FIG. 3B illustrate the relationship of the differences in frequency between the spurious modes and the basic mode (TE0 10 mode). In any of the cases, the dielectric piece with a size of 1 x I mm square and a depth h is buried. In FIG.

2A, the dielectric piece is buried in a position some distance from the center of the dielectric resonator section. In FIGS. 2B and 2C, the depths are 0.6 mm and 1 mm, respectively. In FIGS. 3A, the dielectric piece is buried in the center of the dielectric resonator section. In FIGS. 3B, and 9 (C), the depths h are 0.6 mm and 1 mm, respectively.

As described above, the resonant frequency differences of the neighboring spurious modes to the basic mode can be adjusted with the position in which the dielectric piece is buried, its depth, and its dielectric constant.

In the example shown in FIG. 1, the dielectric piece having a predetermined depth is buried in the upper face of the dielectric plate. For example, as shown in FIG. 4, the dielectric pieces 22a, 22b, and 22c may be buried in the upper face of the dielectric plate 3, and dielectric pieces 22d and 22e in the lower face thereof. In addition, as shown in FIG. 5, the dielectric pieces 22a, 22b, and 22c are so disposed that they are elongated through the upper and lower faces thereof. Further, the dielectric pieces may be buried inside of the dielectric plate 3 without the dielectric piece exposed.

In the above-described embodiment, described is an example of that the dielectric pieces having a different dielectric constant from the dielectric plate are buried. However, as the dielectric pieces, air may be employed. That is, a recess or a perforation may be formed in the dielectric plate.

FIG. 6 shows an example of that recesses 23a, 23b, and 23c are provided in the upper face of the dielectric plate 3. Further, FIG. 7 shows an example of that the recesses 23a, 23b, and 23c are formed in the upper face of the dielectric plate 3, and recesses 23d and 23e in the lower face thereof. Furthermore, FIG. 8 shows an example of that perforations 23a, 23b, and 23c are provided for the dielectric plate 3.

The dielectric resonator device of the present invention may be applied, inter alia, to the dielectric filter, the sharing device, and the oscillator. The dielectric resonator device of the present invention may be applied to different types of high frequency modules including the dielectric resonator.

In addition, the application of the sharing device of the present invention is not restricted to a three-port duplexer such as an antenna sharing device or the like. The sharing device of the present invention may be applied to a multiplexer having at least four ports.

Further, the electronic apparatus of the present invention is not restricted to the communication device including the antenna sharing device, and may be applied to an electronic apparatus which includes the dielectric filter, the sharing device, the oscillator, or the like in its high frequency circuit section.

According to the present invention, the reduction of the non-loading Q factor, caused by the use of the adjusting screw, is eliminated. Thus, when the dielectric filter is configured, the insertion loss can be reduced. Furthermore, since a part of the adjusting screw is prevented from being projected into the outside of the shield case, the apparatus, as a whole, can be easily miniaturized.

The resonant frequency of the resonator section, the coupling factor between the adjacent dielectric resonator sections, the external Q factor, and the spurious characteristics can be adjusted by use of the attachment position of the dielectric chip to the dielectric plate, the formation position of a part having a dielectric constant different from the dielectric plate, the dielectric constant, the size, and the shape of the part. Thus, the adjustment can be carried out in a wide range and with respect to many adjusting items.

Attention is directed to Application No. 9909198.5 (Serial No.) from which this application was divided.

Claims

CLAIMS: 1. A dielectric resonator device comprising electrodes formed on the opposite main faces of a dielectric plate, said electrodes having at least one pair of electrode non-formation sections opposite to each other and having substantially the same shape and size, in which a portion of the dielectric plate sandwiched between said electrode non-formation sections opposite to each other acts as a dielectric resonator section, wherein a part having a different dielectric constant from said dielectric plate is provided inside the dielectric plate in said dielectric resonator section or inside the dielectric plate between adjacent dielectric resonator sections.
2. A dielectric filter including a signal input-output means for inputting or outputting a signal, coupled to the dielectric resonator section according to claim 1.
3. An oscillator including a coupling line coupled to the dielectric resonator section according to claim 1, and a negative characteristic circuit connected to said coupling line.
4. A sharing device including plural signal input-output means according to claim 2, at least one of said signal input-output means being coupled to a plurality of said dielectric resonator sections.
5. An electronic apparatus including in its high frequency circuit section one of the dielectric resonator device according to claim 1, the dielectric filter according to claim 2, the oscillator according to claim 3, and the sharing device according to claim 4.
6. A dielectric resonator device substantially as hereinbefore described with reference to Figures 1 to 8 of the accompanying drawings.