JPS62181506A - Dielectric resonator - Google Patents

Abstract

PURPOSE:To constitute a small-sized filter with excellent spurious characteristic by prolonging at least one of inner and outer conductors toward other end face of a dielectric in a 1/2 wavelength dielectric resonator. CONSTITUTION:The inner conductor 33 is prolonged to the outer conductor 34 and the outer conductor 34 is prolonged to the inner conductor 33 at both end faces of the dielectric 32 respectively. The prolonged part 33a of the inner conductor 33 and the prolonged part 34a of the outer conductor 34 are opposed with an interval (d) on both end faces 32a, 32a of the dielectric 32. Since the prolonged parts 33a, 34a are made close to each other at the interval (d), the static capacitance between the inner conductor 33 and the outer conductor 34 is larger at both the end faces 32a, 32a of the dielectric 32. That is, the resonance frequency of the dielectric resonator 31 is lowered by the static capacitance Cs. Thus, the length of the dielectric 32 is reduced in order to obtain an object resonance frequency.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a 1/2 wavelength dielectric resonator used in filters and the like.

(Prior art) In general, a 1/2 wavelength dielectric resonator is formed by forming an inner conductor and an outer conductor on the inner and outer peripheral surfaces of a cylindrical dielectric material having a length of 1/2 wavelength, respectively. Both ends are open.

Incidentally, as a filter using a dielectric resonator having such a structure, a filter as shown in FIG. 7 has been proposed. The filter shown in FIG. 7 houses dielectric resonators 1.1 to 15 inside a cylindrical exterior case 10, and connects these resonators 11 to 15 sequentially via capacitors C5 to C4. Dielectric resonators 11 and 15 at both ends are connected to capacitors C8 and C, respectively.
62, it is connected to input and output coaxial connectors 16 and 17 attached to the exterior case IO.

In the above filter, in order to improve spurious characteristics, among the five dielectric resonators 11 to 15, three dielectric resonators 12, 13 and 14 are arranged on the inner peripheral surface and the outer peripheral surface as shown in FIG. A low dielectric constant portion 21 having a lower dielectric constant than other portions is formed at the center of a cylindrical dielectric 20 having an inner conductor 18 and an outer conductor 19 formed on its surface.

By the way, in order to realize a dielectric resonator having the structure shown in Fig. 8, a special dielectric material that is difficult to manufacture is used, in which the center part has a low dielectric constant part 2I whose dielectric constant is lower than other parts. There was a problem that required 20.

(Object of the Invention) An object of the present invention is to provide a dielectric resonator that uses a dielectric material that has the same dielectric constant throughout and is easy to manufacture, and can constitute a small filter with excellent spurious characteristics. It is.

(Structure of the Invention) Therefore, the present invention provides that at least seven of the inner conductor and the outer conductor formed on the inner circumferential surface and the outer circumferential surface of a cylindrical dielectric body are directed toward the other at the end face of the dielectric body. It is characterized by being extended. The inner conductor and outer conductor are close to each other at the end face of the dielectric, and the capacitance between them becomes large.

(Effects of the Invention) According to the present invention, since the inner conductor and the outer conductor of the dielectric resonator are close to each other, the inner conductor and the outer conductor are close to each other at the end face of the dielectric. The electrostatic capacitance of the conductor increases and the resonant frequency decreases, and in order to obtain the target resonant frequency, the length of the dielectric material can be shortened, and the spurious characteristics when configuring a filter can be improved. can. Also, the invention? According to this, a dielectric material having the same dielectric constant can be used as a whole, so that a dielectric coaxial resonator can be manufactured easily.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1/2 wavelength dielectric resonator 3 not shown in Figure 1 and Figure 2
1, an inner conductor 33 and an outer conductor 34 are respectively formed on the inner and outer peripheral surfaces of a cylindrical dielectric 32 made of a dielectric material such as barium ditanate, and on both end surfaces of the dielectric 32, The inner conductor 33 extends toward the outer conductor 34, and the outer conductor 34 extends toward the inner conductor 33.

The extended portion 33a of the oriented conductor 33 and the extended portion 34a of the outer conductor 34 are both end surfaces 32a of the dielectric 32.

32a and j-, facing each other with an interval d.

With such a configuration, both end surfaces 32a of the dielectric 32,
At 32a, each extension 33a of the inner conductor 33 and the outer conductor 34
Since the respective extension portions 34a are close to each other with a distance d between them, the capacitance between the inner conductor 33 and the outer conductor 34 becomes large at both end surfaces 32a, 32a of the dielectric 32. That is, the equivalent circuit of the dielectric resonator 31 shown in FIG. 3 has a circuit configuration in which a value of capacitance Cs is connected between each extension portion 33a of the inner conductor 33 and the ground. This capacitance Cs lowers the resonant frequency of the dielectric resonator 31. Therefore, in order to obtain the target resonant frequency, the length of the dielectric 32 is shortened. Furthermore, when a plurality of dielectric resonators 31 are connected via capacitors to form a filter, since the inner conductor 33 has an extension 33a, this extension 33a can be used easily. The capacitor can be electrically connected to the inner conductor 33.

Next, another embodiment of the present invention is shown in FIG.

The dielectric resonator 31' shown in FIG. 4 is the same as the dielectric resonator 31 shown in FIGS. 1 and 2 using a dielectric material 32' whose cross section is square.

In the dielectric resonator 31' of FIG. 4, parts corresponding to those in FIG. 1 are designated by corresponding reference numerals, and redundant explanation will be omitted.

J in Figure 4: Sea urchin, dielectric resonator 3 with a square cross section
1', as shown in FIG.
1°, . . . , 31° can be directly mounted to easily configure a filter.

In FIG. 5 above, the dielectric resonators 31°, 31', . . .
.

31°, the earth conductor 4 of the microwave integrated circuit board 41
The outer conductor 34 of each dielectric resonator 31° is soldered to the ground conductor 42, and the adjacent dielectric resonators 31' and 31' are connected by a capacitor CI+. interconnected. That is, the capacitor CI
The other electrode 43b is soldered to the extension part 33a of the inner conductor 33 of 1°, and the other electrode 43b is connected to the adjacent dielectric resonator 31', 3.
Extension portion 3 of the inner conductor 33 of the other dielectric resonator 31''
3a is soldered (J). As a result, a filter 44 is configured on the microwave integrated circuit random board 41-1-.

The filter 44 has capacitors C12 and C13 between an output conductor 45 of a pre-stage circuit (not shown) formed on the microwave integrated circuit board 4I and a human power conductor 46 of a post-stage circuit (not shown). Inserted via Capacitor C
The electrode 4-3a of the capacitor CI2 and the first input conductor 45 are connected by a ribbon conductor 47, and the electrode 43b of the capacitor CI3 and the first input conductor 46 are connected by a ribbon conductor 48. The electrode 43b of the capacitor C1 is soldered to the extension 33a of the inner conductor 33 of the dielectric resonator 31° at the front stage of the filter 44, and the electrode 43b of the capacitor C13
3a is soldered to an extension 33a of the inner conductor 33 of the final stage dielectric resonator 31' of the filter 44.

The spurious characteristics of the filter 44, the configuration of which has been explained below in -1-, is shown by the solid line h1 in FIG. In addition, the spurious characteristics of a filter using a dielectric resonator in which the extension portions 33a, 33a of the inner conductor 33 are not formed are shown in dotted lines in FIG.
Indicated by From this FIG. 6, in the filter 44 of FIG. 5,
It can be seen that the spurious characteristics are clearly improved compared to the one using a dielectric resonator without the extensions 33a, 33a.

In the above embodiments, it is sufficient that at least one of the inner conductor 33 and the outer conductor 34 of the dielectric resonator 31.degree.
Both are extension portions 33a, respectively.

34a.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an embodiment of the dielectric resonator according to the present invention, FIG. 2 is a longitudinal sectional view of the dielectric resonator of FIG. 1, and FIG. 3 is a cross-sectional view of the dielectric resonator of FIG. 1. An equivalent circuit diagram, FIG. 4 is a perspective view of another embodiment of the dielectric resonator according to the present invention, FIG. 5 is an explanatory diagram of a filter configured using the dielectric resonator of FIG. 4, Fig. 6 is a spurious characteristic diagram of the filter shown in Fig. 5 and the conventional filter. Fig. 7 is an explanatory diagram of the structure of a filter using a conventional dielectric resonator. Fig. 8 is used for the filter shown in Fig. 7. FIG. 3 is a longitudinal cross-sectional view of a dielectric resonator. 31.31°...dielectric resonator, 32.32'...dielectric, 32a...end surface, 33.
...Inner conductor, 33a...Extension part, 34...Outer conductor, 34a...Extension part. Patent applicant: Murata Manufacturing Co., Ltd. Agent: Patent attorney: Mr. Hajime and 2 others = 8-

Claims (1)

[Claims] (1) In a 1/2 wavelength dielectric resonator in which an inner conductor and an outer conductor are formed on the inner and outer circumferential surfaces of a cylindrical dielectric, at least one of the inner conductor and the outer conductor is A dielectric resonator characterized in that the end face of the body extends toward the other end.