JP2000049506A - Method for adjusting characteristics of dielectric filter - Google Patents

Abstract

(57) [Summary] (with correction) [PROBLEMS] To enable characteristic adjustment of a dielectric filter usable in a high frequency band of 5 GHz or more. SOLUTION: A structure in which a plurality of rectangular parallelepiped dielectrics is joined is formed on one surface of each of the dielectrics, an island-shaped input / output electrode surrounded by a ground electrode. A ground electrode is also formed on the surface other than the joint surface of the dielectric, and the resonator is coupled to the joint surface where the dielectric is exposed to form a filter. The portion of the conductor film that is in contact with the dielectric bonding surface of the ground electrode on the surface opposite to the surface on which the input / output electrodes are formed is removed, and the dielectric is exposed at that portion, and the area is adjusted to adjust the bandwidth, etc. Adjust the characteristics of

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting characteristics of a small-sized dielectric filter suitable for use in a high-frequency band of 5 GHz or more, mainly based on the bandwidth.

[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. Up to about 2 GHz band has been used in mobile communication so far, and a filter combined with a dielectric coaxial resonator has been mainly used as a filter used in a mobile station.

[0003] However, when this dielectric coaxial resonator is used at a frequency of 5 GHz or more, it becomes difficult to obtain input / output coupling because the size defined by the frequency becomes thin.
Also, in order to secure a high Q, it is necessary to increase the outer diameter. For example, in order to secure the required Q at a frequency of 5 GHz, an outer diameter of more than 10 mm is required. This goes against the demand for miniaturization of electronic components and is not practical. Alternatively, a TE mode resonator is used, but the structure is increased in size and the input / output coupling structure is complicated.

[0004]

SUMMARY OF THE INVENTION The present invention relates to
An object of the present invention is to provide a dielectric filter which has sufficient filter characteristics in a high frequency band such as GHz, has a high Q, and meets the requirements of miniaturization and thinning. It is another object of the present invention to provide a dielectric filter capable of adjusting characteristics mainly including a bandwidth.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by employing a structure completely different from the conventional structure and removing a part of the conductor film of the ground electrode. .

That is, in a method for adjusting the characteristics of a dielectric filter in which a plurality of rectangular parallelepiped dielectrics are joined, an input / output electrode formed of an island-shaped conductive film is provided on one surface of each dielectric, and the input / output electrodes are connected to each other. It is provided with a ground electrode made of a conductive film which is separated and insulated and is formed on substantially the entire remaining surface of the surface and the entire surface except the bonding surface, and a dielectric is bonded on the bonding surface to form a dielectric filter. It is characterized in that a part of the conductor film of the ground electrode is removed in a portion adjacent to a bonding surface on a surface facing the surface on which the output electrode is formed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the analysis of the resonance mode of a dielectric filter according to the present invention has not been completely performed, it is considered that the dielectric filter has an effect close to that of a waveguide. It is considered that an island-shaped electrode on one surface of the dielectric is used as the input / output structure, and a resonator is coupled at the joint surface where the dielectric is exposed, thereby obtaining filter characteristics.

In the present invention, the conductor film is removed from the portion where the conductor film is removed by removing the portion of the ground electrode opposite to the surface on which the input / output electrodes are formed and in contact with the dielectric bonding surface of the ground electrode. The characteristics are adjusted by changing the electric and magnetic fields.

[0009]

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

A description will now be given of a dielectric filter of the type in which a dielectric material is bonded as a premise of the present invention. FIG. 4 shows a perspective view of the dielectric filter. A 1.1 x 1.1 mm electrode 43, 44 is formed at the center of the 6.0 x 6.0 mm surface of a 6.0 x 6.0 x 2.5 mm rectangular parallelepiped dielectric (dielectric constant 37) 41, 42, and the conductor film ground surrounding it This is one in which electrodes 45 and 46 are formed.

Conductive films are also formed on the other surfaces except for the joint surfaces, and these conductive films are connected to the ground electrodes 45 and 46 and have a ground potential when mounted. The dielectric is exposed at the bonding surface, and an electrode 48 for adjusting the coupling is formed on a part of the bonding surface. In this example, the electrode 48 has a width of 2.0 mm, and connects the ground electrode on the input / output electrode side to the ground electrode on the surface facing the input / output electrode.

FIG. 5 is an explanatory diagram of characteristics of the dielectric filter. With the above configuration, the center frequency is 5.91
0GHz, 3dB bandwidth showed the characteristic of 196MHz.

FIG. 1 is a perspective view showing an embodiment of the present invention.
This is obtained by joining dielectrics of the same size as those shown in FIG. However, a part of the conductor film of the ground electrode on the surface facing the surface on which the input / output electrodes are formed is removed. In this example, the conductor film is removed so that the dielectric is exposed in a rectangular shape from the end face to the center at the portion in contact with the bonding surface of the dielectric.

FIG. 2 shows bandpass characteristics when the conductor film of the ground electrode is removed with a width of 0.5 mm and a length of 2.0 mm to expose the dielectric. At this time, the center frequency was 5.909 GHz and the 3 dB bandwidth was 185 MHz. The bandwidth of about 10 MHz was narrower than the example shown in FIG.

FIG. 3 shows the band pass characteristics when the conductor film of the ground electrode is removed with a width of 1.0 mm and a length of 2.0 mm to expose the dielectric. At this time, the center frequency was 5.901 GHz, and the 3 dB bandwidth was 174 MHz. The bandwidth of about 20 MHz was narrower than the example shown in FIG.

As described above, when the area to be removed is increased, the electric field and the magnetic field leaking from the exposed portion of the dielectric material are increased, the coupling state is changed, and the bandwidth is changed. It is only necessary to scrape the conductor film at the joint as an adjustment after joining the dielectric, which is effective in matching characteristics.

[0017]

According to the present invention, a dielectric filter which can be used in a frequency band of 5 GHz or more and has good characteristics can be obtained. The characteristics can be adjusted only by removing the conductive film, and can be adjusted even after the assembly.

Further, not only the size and thickness can be reduced, but also the dielectric filter can be obtained simply 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 of an embodiment of a dielectric filter to which the present invention is applied.

FIG. 2 is an explanatory diagram of characteristics of the dielectric filter of FIG. 1;

FIG. 3 is an explanatory diagram showing characteristics of another embodiment of the present invention.

FIG. 4 is a perspective view of a dielectric filter to which the present invention is applied.

FIG. 5 is an explanatory diagram of characteristics of a dielectric filter to which the present invention is applied.

[Explanation of symbols]

 11, 12: Dielectric 13, 14: I / O electrode 15, 16: Ground conductor

Claims (3)

[Claims] 1. A method for adjusting characteristics of a dielectric filter in which a plurality of rectangular parallelepiped dielectrics are joined, comprising: an input / output electrode formed of an island-shaped conductive film on one surface of each dielectric;
It has a ground electrode made of a conductor film formed on the entire surface except for the entire surface except for the bonding surface, which is separated and insulated from the input / output electrode, and the dielectric is bonded at the bonding surface. And removing a part of the conductor film of the ground electrode adjacent to the bonding surface of the surface facing the surface on which the input / output electrodes are formed. 2. A method for adjusting the characteristics of a dielectric filter in which a plurality of rectangular parallelepiped dielectrics are joined, comprising: an input / output electrode formed of an island-shaped conductive film on one surface of each of the dielectrics;
It has a ground electrode made of a conductor film formed on the entire surface except for the entire surface except for the bonding surface, which is separated and insulated from the input / output electrode, and the dielectric is bonded at the bonding surface. Wherein a part of the conductor film of the ground electrode adjacent to the bonding surface of the surface opposite to the surface on which the input / output electrode is formed is removed from the end surface side to expose the dielectric. How to adjust the characteristics of the body filter. 3. A method for adjusting characteristics of a dielectric filter in which a plurality of rectangular parallelepiped dielectrics are joined, comprising: an input / output electrode formed of an island-shaped conductive film on one surface of each dielectric;
It has a ground electrode made of a conductor film formed on the entire surface except for the entire surface except for the bonding surface, which is separated and insulated from the input / output electrode, and the dielectric is bonded at the bonding surface. It is characterized in that the exposed area of the dielectric is adjusted by removing a part of the conductor film of the ground electrode in a portion adjacent to the bonding surface of the surface facing the surface on which the input / output electrodes are formed. To adjust the characteristics of the dielectric filter.