JPH11195907A - Dielectric filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a filter capable of obtaining sufficient filter characteristics in a high frequency band and being made small in size and thin in thickness by providing grooves which are located between input-output electrodes and extend from the surface on which the input-output electrodes are formed to the opposite surface on the surfaces perpendicular to the surface on which the input-output electrodes are formed. SOLUTION: Input-output electrodes 11 and 12 which are constituted of an island-shaped conductor film are formed on the surface being the widest area of a rectangular parallelepiped dielectric block 10 with a certain interval. A conductor film 13 which surrounds the electrodes 11 and 12 around the electrodes 11 and 12 with 0.5 mm interval is formed over almost the entire surface of the residual surface. Also, a conductor film is formed on all of the other surfaces other than 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. Grooves 16 and 17 are formed on sides of the dielectric block from both sides 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 made of an island-shaped conductive film formed on a surface having the largest area of the dielectric block at intervals in the longitudinal direction. Comprising 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 on a surface perpendicular to the surface on which the input / output electrode is formed, It is characterized by having a groove located between the input / output electrodes and extending from the surface on which the input / output electrodes are formed to the opposing 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. Comprising 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 on a surface perpendicular to the surface on which the input / output electrode is formed, A groove is provided between the input / output electrodes and extends from the surface on which the input / output electrodes are formed to the opposing surface. The groove is used to adjust the coupling between the resonators.

[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 groove existing 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, grooves 16 and 17 are formed between input / output electrodes 11 and 12 on both sides of the dielectric block from both sides. In this example, the dimensions of the grooves 16 and 17 are 0.3 mm width and depth
There is 2.0mm.

FIG. 2 shows the pass band characteristics of the dielectric filter manufactured by using the dielectric material having a relative dielectric constant of 37 according to the present invention shown in FIG. Center frequency 5.995 GHz, 3 dB bandwidth 0.263 GHz, peak insertion loss 0.848 dB
It was confirmed that the filter can be used as a 6 GHz band band-pass filter.

The characteristics shown in FIG. 3 are obtained by using a dielectric block and input / output electrodes of the same size as in FIG.
It is the case of 2 × 0.3 mm. In this case, the center frequency was 6.047 GHz, the 3 dB bandwidth was 0.145 GHz, the insertion loss at the peak was 1.150 dB, and the pass bandwidth was narrow. This is considered to be because the coupling between the resonators was weakened by the deepening of the groove.

FIG. 4 is a perspective view showing an example in which a groove is formed only on one side. The size of the dielectric block and the shape of the electrode are shown in FIG.
Is the same as the example. 0.5 mm wide and 3.4 mm deep from one side of the dielectric block on a surface perpendicular to the surface where the input / output electrodes are formed
Are formed. FIG. 5 shows the characteristics. In this case, the center frequency was 6.025 GHz, the 3 dB bandwidth was 0.208 GHz, and the insertion loss at the peak was 0.898 dB. FIG. 6 shows the characteristics when the depth of the groove is 3.6 mm, and the center frequency is 6.055 GHz, 3 dB.
0.149 GHz bandwidth, 1.055 dB peak insertion loss
As a result, the pass bandwidth became 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 groove. Also, the coupling state between the resonators can be changed by filling the groove 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 a perspective view showing another embodiment of the present invention.

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

FIG. 6 is an explanatory diagram of characteristics of a dielectric filter according to the present invention.

[Explanation of symbols]

 10, 40: Dielectric block 11, 12, 41, 42: I / O electrode 13, 43: Conductive film (earth electrode) 16, 17, 46: Groove

Claims (4)

[Claims] 1. A dielectric filter integrally formed with 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. Comprising 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 on a surface perpendicular to the surface on which the input / output electrode is formed, Located between input and output electrodes,
A dielectric filter comprising a groove extending from a surface on which input / output electrodes are formed to an opposing 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 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, and is perpendicular to the surface on which the input / output electrode is formed. A dielectric filter, comprising: a groove positioned between input and output electrodes, the groove extending from a surface on which the input and output electrodes are formed to a facing 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. It has an earth electrode made of a conductor film formed on the entire surface of the rest of the surface and the entire surface of the other surface that is separated and insulated from the conductor film of the input / output electrode, and the input / output electrode is connected to the signal input / output line And a groove located between the input and output electrodes and extending from the surface on which the input and output electrodes are formed to a facing surface on a surface perpendicular to the surface on which the input and output electrodes are formed. 4. 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 having the largest area of the dielectric block. Comprising 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 on a surface perpendicular to the surface on which the input / output electrode is formed, Located between input and output electrodes,
A dielectric filter comprising a groove extending from a surface on which input / output electrodes are formed to an opposing surface, and coupling between resonators is adjusted by the groove.