JP2803595B2 - Dielectric filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter used for various communication devices.

[0002]

2. Description of the Related Art A conventional dielectric filter will be described below with reference to the drawings.

FIG. 6 is a perspective view showing a conventional dielectric filter, FIG. 7 is an exploded perspective view, FIG. 8 is a perspective view of the same mounting board, FIG. 9 is an equivalent circuit diagram, and FIG. Is a characteristic waveform diagram.

In FIGS. 6 to 8, a dielectric filter is provided on a mounting substrate 5 having ground patterns 1 and 2 on the front and back surfaces, a circuit configuration pattern 3 and a through hole 4 for short-circuiting the ground patterns 1 and 2 on the front and back surfaces. A dielectric resonator 6 having a connection fitting on the end face on the open end side, and a notch capacitor 7 connected in series with the dielectric resonator 6 are provided.
A capacitor 8 and a coil 9 constituting a low-pass filter are provided.

A capacitor 8 constituting the π-type low-pass filter is provided on the front surface of the mounting board 5 near the end face of the mounting board 5, and the ground is conducted from the end face of the mounting board 5 to the back ground pattern 2. It has become.

An equivalent circuit at this time is as shown in FIG. 9, and a characteristic waveform diagram is shown in FIG.

[0007]

In the above configuration, since the position of the through hole 4 is provided substantially in the middle of the mounting surface of the dielectric resonator 6, the conduction state of the dielectric resonator 6 to the ground is maintained. It is not sufficient, and as shown in FIG. 10, it has affected the attenuation characteristics of high-order harmonics of the dielectric filter.

SUMMARY OF THE INVENTION The present invention solves the above problems, and improves the grounding condition of a dielectric resonator, effectively secures the attenuation characteristics of the dielectric filter, and prevents the occurrence of noise and radio interference. It is intended to provide.

[0009]

In order to achieve the above object, the present invention provides a surface ground pattern provided on a substrate surface.
And circuit configuration pattern, and the back surface provided on the back surface of the substrate
The ground pattern and the surface pattern
Short-circuits the ground pattern on the
A mounting board having a through hole;
A dielectric resonator provided on the
A coil connected between turns, and the circuit configuration pattern
And a capacitor connected between the surface ground pattern
Contact between the circuit configuration pattern and the dielectric resonator.
And a notch capacitor connected therewith.
A valve near the open end of the dielectric resonator,
Connect the ground end of the capacitor near this through hole.
Between the through hole and the ground end of the capacitor.
They are electrically connected .

[0010]

Generally, the charge density is very high in the vicinity of the open end side of the dielectric resonator compared to other portions, and in the present invention, a through hole is formed near the open end of the dielectric resonator having a high charge density. And through the through hole
By connecting the ground end of the dielectric resonator to the ground of the dielectric resonator from this through hole to the ground pattern on the back, the ground with the highest charge density is directly connected to the ground, improving the ground efficiency. As a result, the attenuation characteristics of the dielectric filter are improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a dielectric filter according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a dielectric filter, FIG. 2 is an exploded perspective view of the dielectric filter, and FIG. 3 is a perspective view of a back side of a mounting substrate used for the dielectric filter. 4 is an equivalent circuit diagram of the dielectric filter, and FIG.
3 is a characteristic waveform diagram of the dielectric filter.

In FIG. 1 to FIG. 3, the dielectric filter comprises:
A backside ground pattern 11 is provided on the backside of the board,
Surface ground pattern 10 and circuit configuration pattern 12 on the surface
And the front surface ground pattern 10 and the back surface
A dielectric resonator 15 having a connection fitting on an open end side on a mounting substrate 14 having a through hole 13 for short-circuiting the dielectric pattern 15 and a notch connected in series with the dielectric resonator 15 A capacitor 16, a capacitor 17 and a coil 18 constituting a π-type low-pass filter are provided.

The through hole 13 of the mounting board 14 is provided near the open end of the dielectric resonator 15,
A ground end of the capacitor 17 having one end connected to the ground is provided near the through hole 13, and the ground end of the capacitor 17 is connected to the through hole 13.

An equivalent circuit at this time is as shown in FIG. 4, and a characteristic waveform diagram is as shown in FIG.

The operation of the dielectric filter having the above configuration will be described below. In the vicinity of the open end of the dielectric resonator 15, the charge density is very high as compared with other portions, and the through hole 13 is provided near the open end of the dielectric resonator 15 having a high charge density. The earth of the dielectric resonator 15 is conducted from the through hole 13 to the back surface earth pattern 11, and the earth end of the capacitor 17 constituting the π-type low-pass filter is arranged near the through hole 13. Are also conducted to this through hole 13.

Thus, when the ground end of the capacitor 17 is conducted from the through hole 13, the dielectric resonator 15
Is affected by the flow of charges generated from a very high charge density in the vicinity of the open end, the conduction state to the backside ground pattern 11 is improved, and as a result, high-order harmonic attenuation characteristics are effectively secured. .

As described above, according to the present embodiment, the ground characteristic of the dielectric filter is improved, and the attenuation characteristic of high-order harmonics can be effectively secured. Can be.

Further, in this embodiment, the ground end of the capacitor 17 constituting the π-type low-pass filter is connected to the back ground pattern 11 through the through hole 13. Even when the ground pattern 11 is electrically connected, the distance between the ground end surface of the capacitor 17 and the end surface of the mounting board 14 is larger than the distance between the ground end surface of the capacitor 17 and the through hole 1.
The same effect is obtained as long as the capacitor 17 is provided at a position where the distance with respect to 3 is shorter.

[0020]

As described above, according to the present invention, a through hole is provided near the open end of a dielectric resonator having a high charge density, and a dielectric material is provided from the through hole to the backside ground pattern. By conducting the ground of the resonator, the highest point of the charge is directly conducted to the ground to improve the flow of the charge, and the ground end of the capacitor constituting the π-type low-pass filter near the through hole. By providing, the ground of the capacitor is also taken from the through hole, and the attenuation characteristics of high-order harmonics are effectively ensured, and it is possible to provide a dielectric filter in which noise and radio wave interference are prevented from occurring. it can.

Further, the ground of the capacitor constituting the π-type low-pass filter is not only taken to the back conductor pattern via only the through hole, but also the front ground pattern and the back ground pattern are electrically connected at the end face of the mounting board. Even if the capacitor is provided at a position where the distance between the capacitor and the through hole is shorter than the distance between the capacitor and the end surface of the mounting board, the same effect can be obtained.

[Brief description of the drawings]

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

FIG. 2 is an exploded perspective view of the dielectric filter.

FIG. 3 is a perspective view showing a back surface side of a mounting substrate used for the dielectric filter.

FIG. 4 is an equivalent circuit diagram of the dielectric filter.

FIG. 5 is a characteristic waveform diagram of the dielectric filter.

FIG. 6 is a perspective view showing a conventional dielectric filter.

FIG. 7 is an exploded perspective view of the dielectric filter.

FIG. 8 is a perspective view showing a back surface side of a mounting substrate used for the dielectric filter.

FIG. 9 is an equivalent circuit diagram of the dielectric filter.

FIG. 10 is a characteristic waveform diagram of the dielectric filter.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 Front ground pattern 11 Back ground pattern 12 Circuit configuration pattern 13 Through hole 14 Mounting board 15 Dielectric resonator 16 Notch capacitor 17 Capacitor 18 Coil

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-232605 (JP, A) JP-A-7-162208 (JP, A) JP-A-5-160603 (JP, A) 48401 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) H01P 1/205

Claims (2)

(57) [Claims] 1. A surface ground pattern provided on a substrate surface.
And the pattern for circuit configuration, and the back
Surface ground pattern, provided in the substrate and said
Short-circuit the front ground pattern and the back ground pattern
A mounting board having a through hole;
A dielectric resonator provided on the turn;
A coil connected between the patterns and the circuit configuration pattern;
Connected between the ground and the surface ground pattern
Between the circuit configuration pattern and the dielectric resonator.
A notch capacitor connected to the
In the vicinity of the open end of the dielectric resonator.
The ground end of the capacitor
The through hole and the ground end of the capacitor.
And a dielectric filter electrically connected to the filter. 2. The ground end of the capacitor and the end surface of the mounting board.
Than the distance between the ground end of the capacitor and the through hole.
A capacitor so that the distance from the
The dielectric filter according to claim 1 .