JPH11195906A - Dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a filter which has sufficient filter characteristics in a high frequency band by providing an island-shaped conductor film on the surface of a dielectric block with an interval in a longitudinal direction, providing conductor films over almost the entire residual part of the surface and the other surfaces separating and insulating from the conductor film and extending a through hole on a surface which faces a surface on which input-output electrodes are formed. SOLUTION: Input-output electrodes 11 and 12 which are constituted of an island- shaped conductor film are formed on a surface that is the widest area of a dielectric block 10 of a rectangular parallelepiped with an interval placed and they are input- output electrodes. A conductor film 13 which surrounds the electrodes 11 and 12 around the electrodes 11 and 12 with 0.5 mm interval placed is formed over almost the entire surface except of the residual surface. Also, a conductor film is formed on all of the other surfaces except the surface on which the electrodes 11 and 12 are formed and is made conductive with the electrodes 11 and 12 that surround the film 13 and the whole is made a ground electrode. The electrodes 11 and 12 are connected to an input-output signal line. A through hole which extends to an opposite surface from the surface is formed between the electrodes 11 and 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a small-sized dielectric filter suitable for use in a high frequency band of 5 GHz or more.

[0002]

2. Description of the Related Art With the spread of mobile communication equipment, utilization of a frequency higher than a frequency band currently used is being studied. Conventional mobile communication uses frequencies up to about 2 GHz band, and as a filter used in a mobile station, a combination of a dielectric coaxial resonator and a filter is mainly used.

However, when an attempt is made to use a dielectric coaxial resonator at a higher frequency, the size defined by the frequency becomes thin, so that it is difficult to obtain input / output coupling, and high Q
It is necessary to increase the outer diameter in order to maintain For example,
To ensure the required Q at a frequency of 5 GHz, 10
An outer diameter of several millimeters is required. Alternatively, although a TE mode resonator is used, the structure is increased in size and the input / output coupling structure is complicated.

[0004]

SUMMARY OF THE INVENTION The present invention is to provide a dielectric filter which has sufficient filter characteristics in a high frequency band of 5 GHz to 30 GHz and which meets the demand for miniaturization and thinning.

It is another object of the present invention to provide a dielectric filter whose pass band characteristics can be easily adjusted.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by employing a structure completely different from the conventional structure.

That is, in a dielectric filter integrally formed with a rectangular parallelepiped dielectric block, an input / output electrode formed by an island-shaped conductive film formed at intervals in the longitudinal direction on a surface having the largest area of the dielectric block. A conductive film which is separated and insulated from the conductive film of the input / output electrode and is formed on substantially the entire remaining surface and the entire other surface, and the input / output electrode is formed between the input / output electrodes. It is characterized by having a through-hole extending from the bent surface to the opposite surface.

In a dielectric filter integrally formed with a rectangular parallelepiped dielectric block, an input / output electrode formed by an island-shaped conductive film formed on a surface having the largest area of the dielectric block at intervals in a longitudinal direction. A conductive film which is separated and insulated from the conductive film of the input / output electrode and is formed on substantially the entire remaining surface and the entire other surface, and the input / output electrode is formed between the input / output electrodes. A through hole extending from the bent surface to the opposite surface, and the coupling between the resonators is adjusted by the through hole.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the resonance mode of a dielectric filter according to the present invention has not been completely analyzed, it has the same function as a waveguide, and has a structure in which a dielectric is filled inside the waveguide. It is considered that It is considered that a resonator is constituted by the input and output electrode portions, and the coupling between them is adjusted by the through hole present in the middle.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention. I / O electrodes 1 made of island-shaped conductor film on the widest surface of 12.0 × 6.0 × 2.5 mm rectangular dielectric block 10
1 and 12 are formed at intervals, and these are used as input / output electrodes. The dimensions of the input / output electrodes are 1.4 × 1.4 mm.

A conductor film 13 surrounding the input / output electrodes 11 and 12 is formed over substantially the entire remaining surface of the surface at intervals of 0.5 mm. In addition, a conductor film is formed on all surfaces other than the surface on which the input / output electrodes 11 and 12 are formed, and
Conduction is made with the conductor film 13 surrounding 1 and 12, and the whole becomes a ground electrode. The input / output electrodes 11 and 12 are connected to input / output signal lines.

In the present invention, between the input / output electrodes 11 and 12, a through hole 15 extending from the surface to the opposite surface is formed. In this example, the size of the through hole 15 is 1.4 × 0.3 mm
There is.

FIG. 2 shows the pass band characteristics of the dielectric filter manufactured using the dielectric having a relative permittivity of 37 according to the present invention shown in FIG. The center frequency was 6.006 GHz, the 3 dB bandwidth was 0.240 GHz, and the insertion loss at the peak was 0.871 dB, confirming that the filter can be used as a 6 GHz band band-pass filter.

The characteristics shown in FIG. 3 are obtained when the dielectric block and the input / output electrodes having the same size as those in FIG. 1 are used and the size of the through hole is 1.6 × 0.3 mm. In this case, the center frequency is 6.023 GHz and the 3 dB bandwidth is 0.195 GH
z, the insertion loss at the peak was 0.888 dB, and the passband width was narrow. It is considered that this is because the coupling between the resonators was weakened due to the large through hole.

The characteristics shown in FIG. 4 are obtained by using a dielectric block and input / output electrodes of the same size as in FIG. 1 and making the size of the through hole 1.4 × 0.5 mm. In this case, the center frequency is 6.066 GHz and the 3 dB bandwidth is 0.198 GH
z, the insertion loss at the peak was 0.874 dB, and the pass bandwidth was similarly narrow.

As described above, the characteristics such as the bandwidth can be adjusted by utilizing the fact that the pass band characteristics change depending on the size of the through hole. The coupling state between the resonators can also be changed by filling the through hole with a dielectric or inserting a metal piece.

[0018]

According to the present invention, it is possible to obtain a dielectric filter which can be used in a frequency band of 5 GHz or more and whose characteristics can be easily adjusted.

Further, not only the size and thickness can be reduced, but also the dielectric filter can be manufactured only by forming a conductive film on the surface of a rectangular parallelepiped dielectric, so that a dielectric filter which is easy to manufacture and inexpensive can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of characteristics of a dielectric filter according to the present invention.

FIG. 3 is an explanatory diagram of characteristics of a dielectric filter according to the present invention.

FIG. 4 is an explanatory diagram of characteristics of a dielectric filter according to the present invention.

[Explanation of symbols]

 10: Dielectric block 11, 12: I / O electrode 13: Conductive film (earth electrode) 15: Through hole

Claims (4)

[Claims] 1. A dielectric filter integrally formed on a rectangular parallelepiped dielectric block, wherein the input / output electrodes are formed by island-shaped conductive films formed at intervals in the longitudinal direction on the surface of the dielectric block having the largest area. A conductive film which is separated and insulated from the conductive film of the input / output electrode and is formed on substantially the entire remaining surface and the entire other surface, and the input / output electrode is formed between the input / output electrodes. A through-hole extending from the bent surface to the opposite surface. 2. A dielectric filter integrally formed on a rectangular parallelepiped dielectric block, wherein the input / output electrodes are formed by island-shaped conductor films formed at intervals in the longitudinal direction on the surface of the dielectric block having the largest area. And a ground electrode formed of a conductive film which is insulated and insulated from the conductive film of the input / output electrode and is formed on substantially the entire remaining surface and the entire surface of the other surface. A dielectric filter comprising a through-hole extending from a surface on which is formed to an opposing surface. 3. A dielectric filter integrally formed on a rectangular parallelepiped dielectric block, wherein the input / output electrodes are formed by island-shaped conductive films formed at intervals in the longitudinal direction on a surface having the largest area of the dielectric block. And a grounding electrode formed of a conductive film which is separated and insulated from the conductive film of the input / output electrode and is formed on almost the entire remaining surface and the entire surface of the other surface. The input / output electrode is connected to the signal input / output line And a through-hole located between the input / output electrodes and extending from the surface on which the input / output electrodes are formed to the opposing surface. 4. An input / output electrode comprising an island-shaped conductive film formed at intervals in a longitudinal direction on a surface having the largest area of a dielectric block in a dielectric filter integrally formed with a rectangular parallelepiped dielectric block. A conductor film formed on almost the entire remaining surface and the other surface of the input / output electrode so as to be separated and insulated from the conductor film of the input / output electrode, and extend from the surface on which the input / output electrode is formed to the opposite surface. And a through-hole located between the input and output electrodes, and the coupling between the resonators is adjusted by the through-hole.