JP2000165106A - Dielectric filter, duplexer and communication equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the setting and adjustment of linkage between resonators by forming a cross-shaped groove consisting of a groove to be extended in the arrangement direction of each resonator hole and a groove to be extended perpendicular to the groove between the resonator holes on the side of the short-circuited end surface of a dielectric filter formed by defining one end surface of the dielectric block as the short-circuited end surface. SOLUTION: The cross-shaped groove 8 is formed by the groove to be extended in the arrangement direction of the resonator holes 2a, 2b and the grooves to be extended in the arrangement direction and in the direction perpendicular to the resonator holes 2a, 2b. The horizontal groove is formed without linking both ends of the groove with the resonator holes 2a, 2b at specified intervals from the resonator holes 2a, 2b. The groove in the direction perpendicular to the resonator holes is formed so that it passes from one side to the other of the dielectric block 1. An external conductor 6 is formed on the front surface of the cross-shaped groove 8. The dielectric filter is constituted of a band-pass filter consisting of two stages of the resonators corresponding to the resonator holes 2a, 2b and synthetic linkage between the linkage due to stray capacity to be caused in a part (g) where no internal conductor is formed and the linkage due to the cross-shaped groove 8 is formed by two resonators.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter and a duplexer used in, for example, a microwave band, and a communication device using the same.

[0002]

2. Description of the Related Art Conventionally, in a dielectric filter having a plurality of resonator holes formed in a dielectric block, in order to obtain coupling between the resonators, for example, a groove connecting the resonator holes is provided on the short-circuit end face side. It is known that a groove is provided or a groove is provided between the resonator holes on the short-circuit end face side in a direction perpendicular to the arrangement direction of the resonator holes. The former groove functions to block the odd-mode magnetic field and enhance the inductive coupling, and the latter groove functions to block the even-mode magnetic field and enhance the capacitive coupling. The degree of coupling between the resonators is adjusted by changing the depth and width of the groove.

[0003]

However, in the conventional dielectric filter, each groove provided on the side of the short-circuit end face can only adjust one of inductive coupling and capacitive coupling. , It was difficult to easily obtain the required bonding. In other words, when the external dimensions and the distance between the resonator holes are set, there is a limit in setting and adjusting the required coupling property and degree of coupling, and there is a degree of freedom in design for obtaining desired filter characteristics. Was low.

An object of the present invention is to provide a dielectric filter capable of easily setting and adjusting the coupling between resonators,
An object of the present invention is to provide a duplexer and a communication device using the same.

[0005]

According to a first aspect of the present invention, there is provided a dielectric filter, wherein an inner conductor is formed on an inner surface of the dielectric block through a pair of opposed end surfaces of the dielectric block. A plurality of resonator holes are formed in parallel, an outer conductor is formed on an outer surface of the dielectric block, and a dielectric filter having one end surface of the dielectric block as a short-circuit end surface is provided between the resonator holes on the short-circuit end surface side. And a cross-shaped groove formed by a groove extending in the arrangement direction of the resonator holes and a groove extending in a direction perpendicular to the groove.

A dielectric filter according to a second aspect is characterized in that, in the dielectric filter according to the first aspect, the cross-shaped groove is formed without being connected to the resonator hole.

According to a third aspect of the present invention, in the duplexer, at least two or more filter portions are formed on the dielectric block,
Claim 1 or Claim 2 wherein at least one filter section is provided.
Wherein the dielectric filter is characterized in that:

According to a fourth aspect of the present invention, there is provided a communication device, comprising: the dielectric filter according to the first or second aspect;
And at least one of the duplexers described in (1).

In a dielectric filter in which a plurality of resonator holes are formed in a single dielectric block, an odd-mode magnetic field circulating in a circle around each resonator hole is adjacent between the resonator holes. There is an even mode magnetic field orbiting around the outside between the resonator holes in an elliptical shape, and the coupling between the resonators is obtained by the stronger mode magnetic field. Of the above-mentioned cross-shaped grooves, the groove extending in the arrangement direction of the resonator holes acts to block the odd-mode magnetic field, but does not block the even-mode magnetic field. Function to increase. On the other hand, the groove extending in the vertical direction acts to block the even-mode magnetic field, but does not block the odd-mode magnetic field, and thus functions to increase the coupling by the odd-mode magnetic field, that is, the degree of coupling of the capacitive coupling. I do. Increasing the depth, width and length of the groove in any direction,
The degree of coupling of each increases.

In the dielectric filter and the duplexer having the above-described structure, a cross-shaped groove having a function of adjusting the degree of coupling of inductive coupling and capacitive coupling is formed between the resonator holes on the short-circuit end face side. By changing the depth, width or length of the groove in each direction, it is possible to finely adjust the coupling between the resonators, and to obtain the required coupling property (inductive coupling or capacitive coupling). ) And the required degree of coupling can be easily obtained. That is, the degree of freedom of coupling between the resonators can be increased by the coupling using the cross-shaped grooves, and desired favorable characteristics can be easily realized without changing the external dimensions and the pitch between the resonator holes. .

Further, by forming the cross-shaped grooves (grooves in the arrangement direction) so as not to be connected to the resonator holes, the Qo of the resonator is improved as compared with the case where the cross-shaped grooves are formed to be connected to the resonator holes. And deterioration of insertion loss can be prevented.

Further, the communication apparatus according to the present invention is provided with the dielectric filter or the dielectric duplexer having the above-mentioned characteristics, and thus has excellent characteristics.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a dielectric filter according to a first embodiment of the present invention will be described with reference to FIGS. This dielectric filter has a substantially rectangular parallelepiped dielectric block 1.
It has. In the dielectric block 1, two resonator holes 2a and 2b penetrating from the first end face 1a to the second end face 1b opposed thereto are formed. Resonator holes 2a, 2b
Are arranged in parallel with each other and in a line.
An inner conductor 5 is formed on the inner peripheral surface of each of the resonator holes 2a and 2b, and an outer conductor 6 is formed on the outer surface of the dielectric block 1. The inner conductor 5 of each resonator hole 2a, 2b is provided with an inner conductor non-formed portion g near the first end face 1a and is separated from the outer conductor 6, and this portion is an open end. 2nd end face 1b
In this case, each inner conductor 5 is connected to an outer conductor, and the second end face 1b is a short-circuit end face. The first surface of the dielectric block 1
Terminal electrodes 7a and 7b insulated (separated) from the outer conductor 6 are formed over both side surfaces near the end surface 1a. The terminal electrodes 7a and 7b and the inner conductor 5 of the resonator holes 2a and 2b are coupled by electrostatic capacitance, and external coupling is obtained by this capacitance.

A cross-shaped groove 8 is formed between the resonator holes 2a and 2b on the side of the second end face 1b serving as a short-circuit end face. The cross-shaped groove 8 includes a groove (a horizontal groove in FIG. 2) extending in the arrangement direction of the resonator holes 2a and 2b and the resonator holes 2a and 2b.
2b and grooves extending in the vertical direction (vertical grooves in FIG. 2). Both ends of the horizontal groove are formed at a predetermined distance from the resonator holes 2a, 2b, that is, without being connected to the resonator holes 2a, 2b. The vertical groove is formed so as to pass from one side surface of the dielectric block 1 to the other side surface. The outer conductor 6 is formed on the entire surface of the cross-shaped groove 8. The width and depth of the groove in each direction are formed with different dimensions.

This dielectric filter has resonator holes 2a and 2a.
The two resonators are constituted by a band-pass filter composed of two-stage resonators corresponding to the b. The two resonators are electromagnetically coupled by the combined coupling of the stray capacitance generated in the inner conductor non-formed portion g and the coupling by the cross-shaped groove 8. Tied together. To increase the degree of coupling of the inductive coupling, the depth, width or length of the horizontal groove is set to be large, and the depth or width of the vertical groove is set to be small. Conversely, when increasing the degree of coupling of the capacitive coupling, the depth or width of the vertical groove is set to be large, and the depth, width or length of the horizontal groove is set to be small.

Next, the configuration of a duplexer (antenna duplexer) according to a second embodiment of the present invention will be described with reference to FIG. The duplexer includes a dielectric block 1 having a substantially rectangular parallelepiped shape, and includes resonator holes 2 a to 2 f and an external coupling hole 3 that penetrate from the first end face 1 a to the second end face 1 b and have an inner conductor 5 formed on the inner face. The outer conductor 6 is formed on the outer surface of the dielectric block 1. The inner conductor 5 of each of the resonator holes 2a to 2f has an inner conductor non-formed portion g near the first end face 1a, and this portion is an open end. On the second end face 1b, the inner conductor 5 of each of the resonator holes 2a to 2f is connected to the outer conductor 6. The resonator holes 2a and 2b and the external coupling hole 3 are formed by straight holes d having the same diameter over the entire length, and the resonator holes 2c to 2f are large in diameter on the first end surface 1a side and on the second end surface 1b. The side is formed with a small step hole. On the outer surface of the dielectric block 1, terminal electrodes 7a, 7b, 7c insulated from the outer conductor 6 are formed.
The inner conductor 5 of the outer coupling hole 3 is connected to the outer conductor 6 at the first end face 1a, and is connected to the terminal electrode 7b at the second end face 1b. The terminal electrodes 5a, 5c and the inner conductors 5 of the resonator holes 2a, 2f are coupled by capacitance, and the inner conductor 5 of the outer coupling hole 3 and the inner conductor 5 of the resonator holes 2c, 2d are interdigitally coupled. ing. The terminal electrode 7a functions as a transmitting terminal, the terminal electrode 7c functions as a receiving terminal, and the terminal electrode 7b functions as an antenna terminal.

A cross-shaped groove 8a is formed between the resonator holes 2a and 2b, and a cross-shaped groove 8b is formed between the resonator holes 2d and 2e. Have been. An outer conductor 6 is formed on the entire surface of the cross-shaped grooves 8a and 8b. The vertical groove of the cross-shaped groove 8a is formed so as to pass through between the opposing side surfaces as in the first embodiment, but the vertical groove of the cross-shaped groove 8b is spaced a predetermined distance from the opposing side surface. It is formed.

In this duplexer, the transmitting side has a resonator hole 2
The receiving side is composed of a band-pass filter composed of three stages of resonators corresponding to the resonator holes 2d to 2f. Each resonator is coupled by a stray capacitance generated in the inner conductor non-formed portion g or by a step hole, and both resonators of the resonator holes 2a and 2b are cross-shaped grooves 8a.
The coupling is adjusted by a, and the coupling of both resonators of the resonator holes 2d and 2e is adjusted by the cross-shaped groove 8b.

As described above, by using the connection by the cross-shaped groove and the other connection means together, more various characteristics can be realized. Also, as in the present embodiment, the cross-shaped groove does not need to be formed between all the resonators, but is provided at an appropriate location according to the required filter characteristics.

It should be noted that the dielectric filter and the duplexer according to the present invention are not limited to the above embodiments, but can be variously modified within the scope of the invention.
For example, in each of the embodiments described above, the open end of each resonator is formed at a position deeper than the end face of the dielectric block, but the first end face 1a is formed without forming an outer conductor on the first end face 1a. May be an open end.

Next, the configuration of a communication device according to a third embodiment of the present invention is shown in FIG. In FIG. 4, 122 is an antenna, 123 is a duplexer, 124 is a transmission filter,
Reference numeral 125 denotes a reception filter, 126 denotes a transmission circuit, and 127 denotes a reception circuit. The antenna terminal ANT of the dielectric duplexer 123 is connected to the antenna 122, the transmission terminal Tx is connected to the transmission circuit 126, and the reception terminal RX is connected to the reception circuit 127, thereby forming a communication device.

Here, the dielectric filter of the first embodiment can be used as the transmission filter 124 or the reception filter 125, and as the duplexer 123,
The duplexer of the second embodiment can be used.
By using the dielectric filter or the duplexer according to the present invention, a communication device having good characteristics can be realized.

[0023]

As described above, the dielectric filter or the duplexer according to the present invention has a function of adjusting the degree of coupling between inductive coupling and capacitive coupling between resonator holes on the short-circuit end face side. Since the groove is formed, the required connectivity and degree of coupling can be easily obtained by changing the depth, width or length of the groove in each direction. Therefore, a dielectric filter or duplexer having the required bandwidth and attenuation characteristics can be easily obtained.

Further, by forming the cross-shaped grooves (grooves in the arrangement direction) so as not to be connected to the resonator holes, the Q of the resonator is improved.
o can be prevented, and thus the insertion loss can be prevented from deteriorating.

Further, by mounting the dielectric filter or the dielectric duplexer according to the present invention, it is possible to obtain a communication device having good characteristics.

[Brief description of the drawings]

FIG. 1 is a perspective view of a dielectric filter according to a first embodiment.

FIG. 2 is a plan view of a short-circuit end face of the dielectric filter according to the first embodiment.

FIG. 3 is a perspective view of a duplexer according to a second embodiment.

FIG. 4 is a block diagram of a communication device according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric block 2a-2f Resonator hole 5 Inner conductor 6 Outer conductor 7a-7c Terminal electrode 8, 8a, 8b Cross-shaped groove

Claims (4)

[Claims] A plurality of resonator holes having an inner conductor formed on an inner surface thereof are formed in parallel with each other and penetrate between a pair of opposed end surfaces of the dielectric block, and an outer conductor is formed on an outer surface of the dielectric block. In a dielectric filter having one end face of a dielectric block as a short-circuit end face, between the resonator holes on the short-circuit end face side, a groove extending in the arrangement direction of each resonator hole and a groove extending in a direction perpendicular to the groove. A dielectric filter, wherein a cross-shaped groove is formed. 2. The dielectric filter according to claim 1, wherein the cross-shaped groove is formed without being connected to the resonator hole. 3. A duplexer, wherein at least two or more filter units are formed in a dielectric block, and at least one of the filter units is the dielectric filter according to claim 1 or 2. 4. A communication device comprising at least one of the dielectric filter according to claim 1 or 2, and the duplexer according to claim 3.