JP2803541B2 - Coaxial dielectric resonator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial dielectric resonator used for communication equipment such as portable radio equipment.

[0002]

2. Description of the Related Art In recent years, coaxial dielectric resonators having one end short-circuited have been widely used in filters, VCOs, and the like as devices have become smaller and more sophisticated.

A conventional coaxial dielectric resonator will be described below with reference to FIGS. FIG. 5 is an equivalent circuit diagram of a coaxial dielectric resonator, and FIG. 6 is a perspective view showing a conventional coaxial dielectric resonator.

In FIG. 5, reference numeral 10 denotes a coaxial dielectric resonator. One end of the coaxial dielectric resonator 10 is short-circuited, and the other end is connected to a terminal 11 for connection to the outside. 1 is a coaxial dielectric, 2 is an inner conductor, 3 is an outer conductor, and 4 is a short-circuit conductor. Reference numeral 12 denotes an external connection terminal which is connected to the internal conductor 2 by press-fitting or soldering into a coaxial portion of the dielectric. FIG. 7 is a sectional view when the coaxial dielectric resonator of FIG. 6 is mounted on a circuit board. 7 is a circuit board, 8 is a ground electrode of the circuit board, 9 is a hot electrode of the circuit board, and the external conductor 3 and the ground electrode 8 and the external connection terminal 1
2 and the hot electrode 9 are connected by soldering or the like.

FIG. 8 is a perspective view of another conventional coaxial dielectric resonator, in which 21 is a coaxial dielectric, 22 is an inner conductor,
3 is an outer conductor, and 24 is a short-circuit conductor. Reference numeral 25 denotes an external connection conductor which is connected to the internal conductor 22 by partial plating or printing and baking an electrode pattern on the open end of the dielectric.

FIG. 9 is a cross-sectional view when another conventional coaxial dielectric resonator of FIG. 8 is mounted on a circuit board. 27 is a circuit board, 28 is a ground electrode of the circuit board, 29 is a hot electrode of the circuit board, and the external conductor 23 and the ground electrode 28 and the external connection conductor 25 and the hot electrode 29 are connected by solder 26 or the like.

[0007]

However, in the conventional configuration shown in FIG. 6, the size of the terminal 11 for connecting the internal conductor to another circuit is reduced as the coaxial dielectric resonator is reduced in size. It is becoming very difficult to do. For example, assuming that the relative permittivity (Er) of the coaxial dielectric resonator is 95, the length (L) of the coaxial dielectric resonator is given by the following equation: L = C / (4 × Er × f) f: Resonance frequency, C: speed of light, and the length when the resonance frequency is 1 [GHz] is about 7.7.
mm. When a terminal 11 for connection to the outside is attached to this coaxial dielectric resonator, its total length is about 9.7 m.
m, and about 21% is dead space.
When the outer diameter of the coaxial dielectric resonator is 2.5 mm, the inner diameter must be about 0.9 mm in order to maximize the no-load Q. However, there is a problem in that it is impossible to manufacture the terminal 11 having the above structure and the cost is high.

In the conventional configuration shown in FIG. 8, in order to solve the problem of the coaxial dielectric resonator shown in FIG.
5 is formed on the open end of the coaxial dielectric 21 by partial plating or the like to reduce the overall length.

However, in order to obtain a predetermined resonance frequency, the coaxial dielectric resonator having the above-mentioned structure is required to reduce the length of the coaxial dielectric resonator to a certain length by parallel polishing or the like as shown in the above equation. After that, the external connection conductor 25 must be formed by partial plating or the like, resulting in a very high cost and at the same time an arbitrary resonance frequency (resonator length)
There is a problem that it is difficult to cope with the problem.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and has high reliability in surface mounting on a circuit board and the like, enables high-density mounting, and at the same time is inexpensive and mass-produced. The purpose is to provide equipment.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a slit on an open end face of a coaxial dielectric resonator, and uses a conductor provided on an inner peripheral surface of the slit to form a dielectric with an internal conductor. An external connection conductor provided near the open end face on the outer peripheral surface of the body is connected, and the external connection conductor is not connected to another external conductor.

[0012]

According to the present invention, since the external connection conductor is provided on the outer peripheral surface of the coaxial dielectric resonator according to the above-described structure, the total length when mounted on the circuit board can be shortened, and the inner conductor and the outer conductor can be connected. Since the external connection conductor on the surface is connected by a conductor provided on the inner peripheral surface of the slit, it can be easily processed to any resonance frequency length within the range of the slit depth. Lower prices can be achieved.

[0013]

FIG. 1 is a perspective view of a coaxial dielectric resonator according to an embodiment of the present invention. In FIG. 1, 3
1 is a cylindrical coaxial dielectric, 32 is an inner conductor, 33 is an outer conductor, 34 is a short-circuit conductor, 35 is a slit, and 36 is an external connection conductor. The external connection conductor 36 is formed by the conductor provided on the inner peripheral surface of
And is not connected to another external conductor 33.

FIG. 2 is a sectional view when the coaxial dielectric resonator according to the embodiment of the present invention shown in FIG. 1 is mounted on a circuit board. 37 is a circuit board; 38 is a ground electrode of the circuit board; 39 is a hot electrode of the circuit board;
The ground electrode 38, the external connection conductor 36, and the hot electrode 39 are connected by soldering or the like.

The equivalent circuit of the coaxial dielectric resonator constructed as described above has the same circuit as that shown in FIG. 5, and has an external connection conductor on the outer peripheral surface and a short-circuited one end. Acts as a vessel.

According to this embodiment as described above, the external connection terminal 12 as shown in FIG. 6 is not required, and when mounted on a circuit board, the hot electrode 39 is provided on the portion facing the external connection conductor 36. May be provided. For example, the relative permittivity (E
r) When a coaxial dielectric resonator having a resonance frequency (f) of 1 GHz is mounted on a circuit board using a dielectric of 95, FIG.
The conventional coaxial dielectric resonator shown in FIG. 7 requires an external connection terminal 12, and its total length is about 9.7 mm in consideration of a soldering land with a circuit board. In the resonator, the length is about 7.7 mm, and the overall length can be reduced by 21%, and the mounting efficiency can be increased. At the same time, unlike the conventional example, the external connection terminals 12 are not required, so that the assembly cost is reduced, and three-dimensional wiring is eliminated, so that the reliability is improved.

Further, in the conventional coaxial dielectric resonator shown in FIG. 8, in order to obtain a predetermined resonance frequency, the coaxial dielectric resonator is processed in advance to a predetermined length by parallel polishing or the like, and then partially plated. In this case, the external connection conductor 25 must be formed, which is extremely expensive, and at the same time cannot cope with other resonance frequencies. However, in the coaxial dielectric resonator of the present embodiment, the slit 35 is formed by a mold when forming the coaxial dielectric in the production process, or the slit 35 is formed by processing or the like. If conductors are formed by plating or silver electrodes,
The length of the coaxial dielectric resonator can be arbitrarily processed within the range of the depth of the slit 35. For example, the relative permittivity (E
r) When the depth of the slit 35 of the coaxial dielectric resonator having a resonance frequency (f) of 1 GHz is set to 2 mm using a dielectric material of 95, the resonance frequency can be extremely easily reduced by about 30% by processing.
Could be changed.

Further, in the embodiment of the present invention, the cross-sectional shape of the inner conductor is a uniform circular shape. However, this is not necessary, and the size of the diameter may be changed stepwise or continuously. It may be. Further, in the embodiment of the present invention, the cross-sectional shape of the outer shape of the coaxial dielectric resonator is a uniform square, but the size of the diameter may be changed stepwise or continuously, or the shape may be rectangular, It may be circular. Further, in order to finely adjust the resonance frequency, a part of the outer conductor, the short-circuit conductor, the inner conductor, and a part of the dielectric may be peeled off by trimming or the like. Hereinafter, another embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a perspective view of a coaxial dielectric resonator according to another embodiment of the present invention. In FIG. 3, 41 is a cylindrical coaxial dielectric, 42 is an inner conductor, 43
Is an external conductor, 44 is a short-circuit conductor, 45 is a slit, 46 is an external connection conductor, and 50 is a portion where a part of the conductor and the dielectric is peeled off by trimming or the like. The cross-sectional shape of the internal conductor 42 changes stepwise, the cross-sectional shape on the short-circuit surface side is circular, and the cross-sectional shape on the open end side is rectangular. In addition, the external connection conductor 46 is
5 is connected to the inner conductor 42 by a conductor provided on the inner peripheral surface and is not connected to the other outer conductor 43.

FIG. 4 is a sectional view of another embodiment of the present invention shown in FIG. 3 when the coaxial dielectric resonator is mounted on a circuit board. 47 is a circuit board; 48 is a ground electrode of the circuit board; 49 is a hot electrode of the circuit board;
The ground electrode 48, the external connection conductor 46, and the hot electrode 49 are connected by soldering or the like.

The equivalent circuit of the coaxial dielectric resonator constructed as described above has the same circuit as that shown in FIG. 5, has a conductor for external connection on the outer peripheral surface, and has a short-circuited one end. By changing the shape of the internal conductor at the same time, the characteristic impedance is changed to change the resonance frequency and the frequency of the harmonic.

According to the present embodiment as described above, the length of the coaxial dielectric resonator can be further reduced by changing the shape of the internal conductor 42. For example, when the relative dielectric constant (Er) of the dielectric of the coaxial dielectric resonator of FIG. 1 is 95, when the resonance frequency (f) is 1 GHz, the length becomes:
Although it was about 7.7 mm, in the embodiment of FIG.
If the length of one side is 3 mm, the diameter of the short-circuit surface side of the internal conductor 42 is 0.8φ, the length of the circular portion is 2 mm, and the length of one side of the open end side of the internal conductor 42 is 2 mm, the coaxial dielectric The total length of the resonator was 4.4 mm, which was about 43% shorter than that of the embodiment of FIG. Further, the trimming unit 50
The resonance frequency can be changed by several tens of MHz by providing the above, and the resonance frequency can be easily changed after being mounted on the circuit board 47 as shown in FIG.

In this embodiment, the length of the coaxial dielectric resonator is shortened by making the cross-sectional shape of the internal conductor on the short-circuit side smaller than the cross-sectional shape of the internal conductor on the open end side. Conversely, by increasing the length, the length of the coaxial dielectric resonator can be intentionally increased. Although the trimming section 50 is provided near the open end, it may be provided near the short-circuit end and near the short-circuit end for the purpose of lowering the resonance frequency.

[0024]

According to the present invention, a slit is provided on an open end face of a coaxial dielectric resonator, and a conductor provided on an inner peripheral face of the slit is provided near an open end face on an inner conductor and an outer peripheral face of the dielectric. The external connection conductor is connected to the external connection conductor, and the external connection conductor is not connected to other external conductors.This eliminates the external connection terminals required for mounting on a conventional circuit board. Enables highly reliable surface mounting,
The overall length during mounting is shortened, enabling high-density mounting without dead space . Also, by providing a conductor in the slit
Therefore, even after the conductor has been formed, polishing is performed on the open end side of the resonator.
Resonator length within the range of slit depth by means such as grinding
Can be adjusted to make the resonance frequency shorter.
Fine adjustment of characteristics and the like can be easily performed.

[Brief description of the drawings]

FIG. 1 is a perspective view of a coaxial dielectric resonator according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view when a coaxial dielectric resonator according to one embodiment of the present invention is mounted on a circuit board.

FIG. 3 is a perspective view of a coaxial dielectric resonator according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view when a coaxial dielectric resonator according to another embodiment of the present invention is mounted on a circuit board.

FIG. 5 is an equivalent circuit diagram of a coaxial dielectric resonator.

FIG. 6 is a perspective view showing a conventional coaxial dielectric resonator.

FIG. 7 is a cross-sectional view when a conventional coaxial dielectric resonator is mounted on a circuit board.

FIG. 8 is a perspective view of another conventional coaxial dielectric resonator.

FIG. 9 is a sectional view when another conventional coaxial dielectric resonator is mounted on a circuit board.

[Explanation of symbols]

 31 Coaxial dielectric 32 Internal conductor 33 External conductor 34 Short-circuit conductor 35 Slit 36 External connection conductor 37 Circuit board 38 Ground electrode 39 Hot electrode

──────────────────────────────────────────────────の Continued on the front page (72) Kazuhiro Eguchi 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Hiroshi Ohno 1006 Kadoma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (56) References JP-A-2-182003 (JP, A) JP-A-1-305702 (JP, A) JP-A-4-137901 (JP, A) JP-A-63-55604 (JP, U) Hikaru Hei 2-84408 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01P 7/04 H01P 1/212 H01P 5/08

Claims (2)

(57) [Claims] 1. A cylindrical dielectric having a slit on one end surface, an external conductor provided on an outer peripheral surface of the dielectric, and an outer conductor provided on an outer peripheral surface of the dielectric so as to be separated from the outer conductor. A conductor for external connection, an internal conductor provided on the inner peripheral surface of the dielectric, a short-circuit conductor provided on the other end surface of the dielectric to short-circuit the internal conductor and the external conductor, And a conductor for short-circuiting the internal conductor and the external connection conductor is provided. 2. The coaxial dielectric resonator according to claim 1, wherein a step is provided in the through hole of the dielectric, and a cross-sectional area of the through hole is made different.