JPH03145803A - Dielectric filter - Google Patents

Abstract

PURPOSE:To attain small size and low cost by expanding partially a resonator inner conductor layer in the vicinity of an open end of the resonator in a tri- plate dielectric filter so as to reduce the effect of the dielectric substance onto an electric characteristic. CONSTITUTION:A TEM mode resonator 51 is constituted in a tri-plate dielectric filter 11 by contacting two dielectric plates 21, 31 of the same shape closely, using an outer side as an earth face 4 of the conductor layer and arranging a resonator inner conductor layer 61 onto the close contact face, and the resonator inner conductor 61 near the open end 65 of the resonator 51 is partially expanded, the same shape of the dielectric plates 21, 31 is used within a range of a characteristic to cover the difference by changing the shape of the resonator inner conductor layer 61 only thereby improving the productivity. Moreover, the vicinity of the open end 65 is expanded in the shape of the resonator inner conductor layer 61 to expand the area, the fringing capacitor C entering between the open end and the earth is increased to reduce the length L of the resonator 51 thereby reducing the length of one side of the dielectric plates 21, 31 and attaining miniaturization.

Description

[Detailed Description of the Invention] [Summary] Regarding a triplate type dielectric filter, the dielectric portion has little influence on electrical characteristics (if possible, it is made irrelevant, and a small and low-cost dielectric filter is provided. For this purpose, we constructed a TEM mode resonator by placing two dielectric plates of the same shape in close contact with each other, using the outer surface as the grounding surface of the conductive layer, and arranging the internal conductor layer on the contact surface. This is a triplate type dielectric filter, and is configured so that a conductive layer within the resonator near the open end of the resonator is partially enlarged.

[Industrial application field]

The present invention relates to a triplate dielectric filter.

In recent years, wireless communication has made remarkable progress in the mobile communication field due to miniaturization and improved performance.

For example, car phones, mobile phones, or home wireless phones are rapidly becoming popular.

Dielectric filters used in the 800 MHz band and quasi-microwave band of these mobile radios have been made smaller as dielectric materials have higher dielectric constants.

However, there is a strong demand for further miniaturization and cost reduction, and as this progress progresses, the fields of use will be further expanded, and it is also expected that it will lead to the development of new fields and contribute to expanding demand and making life more convenient. .

[Prior art] Figure 6(a) is a perspective view of a conventional example, and Figure Cb) is the same.
-A cross-sectional view is shown.

As a conventional example, as shown in FIG. 6(a), there is a dielectric filter 91 in which three TEM mode resonators 95 are arranged in a rectangular parallelepiped dielectric block 92.

The dielectric block 92 has a conductive layer formed by metallization on the outer surface except for the negative surface 93 to serve as a ground surface 94. Furthermore, on one surface 93 where there is no ground surface 94, there are three conductive layers arranged at predetermined intervals in a line in the center. A through hole is bored, and as shown in Figure 3), its inner surface is metallized to form a conductive layer, one end is electrically connected to a ground plane 94, and the other end is an open end 96, forming a TEM mode resonator 95. The length of the through hole of each resonator 95 corresponds to approximately 174 wavelengths of the resonant frequency, and the degree of coupling and sharpness between the resonators 95 are determined by the hole diameter and interval of the through hole.

For the input and output of the circuit, a coupling pattern 97 is provided on the side surface near the resonator 95 at both ends insulated from the ground plane 94, and this area provides a predetermined degree of coupling. External input and output circuits are connected to.

The center resonant frequency of the resonator 95 is adjusted by directly cutting the conductive layer at the open end 96 from the end.

[Problem to be solved by the invention]

However, (1) The dielectric block 92 of the dielectric filter 91 changes every time the specifications of electrical characteristics such as center frequency and passband width change.
The external shape of the through hole, the diameter of the through hole, and the spacing must be changed.

(2) The process of drilling through holes in the dielectric block 92 requires many man-hours and reduces yield, and in the case of die forming, the cost of the die is high.

(2) In addition, a prototype cannot be produced until the dielectric block 92, which bears all the characteristics, is completed, which requires the longest manufacturing period. This limits the cycle time for prototyping and
There are limits to shortening.

There were problems such as.

SUMMARY OF THE INVENTION In view of these problems, it is an object of the present invention to provide a small, low-cost dielectric filter in which the dielectric portion has little influence on electrical characteristics, and if possible, is made irrelevant.

[Means to solve the problem]

The above problems are solved as shown in Figs. 1 to 5: (1) Two dielectric plates 21 and 31 having the same external shape are brought into close contact with each other, and the outer surface is used as the ground plane 4 of the conductive layer, so that resonance occurs on the adhering surface. A triplate type dielectric filter 11 in which a TEM mode resonator 51 is configured by disposing an internal conductor layer 61, in which the internal conductor layer 61 near the open end 65 of the resonator 51 is partially disposed. The problem is solved by the dielectric filter of the present invention.

(2) Also, two dielectric plates 22 and 32 having the same external shape are brought into close contact with each other, the outer surface is used as the ground plane 4 of the conductive layer, and the internal conductive layer 62 in the resonator is arranged on the contact surface to form a TEM mode resonator. 52, the ground plane 4 of the dielectric plate 22.32 facing the vicinity of the open end 65 of the intra-resonator conductor layer 62 is partially provided with a recess 42. This problem is solved by the dielectric filter of the present invention, which can approach a predetermined value.

(3) Also, two dielectric plates 23 and 33 having the same external shape are brought into close contact with each other, the outer surface is used as the ground plane 4 of the conductive layer, and the internal conductor layer 62 is placed on the contact surface to form a TEM mode resonator. A triplate type dielectric filter 13 configured with 53,
This problem is solved by the dielectric filter of the present invention, in which the ground plane 4 of the dielectric plate 23, 33 facing the vicinity of the open end 65 of the intra-resonator conductor layer 62 is brought close to a predetermined position by partially providing a groove 43.

(4) Also, two dielectric plates 24 and 34 having the same external shape are brought into close contact with each other, the outer surface is used as the ground plane 4 of the conductive layer, and the internal conductor layer 64 in the resonator is arranged on the contact surface to achieve resonance in the TEM mode. The triplate type dielectric filter 14 has a plurality of resonators 54 arranged in an interdigital type in which the directions of the open ends 65 are staggered, and two dielectric plates 24. This problem is solved by the dielectric filter of the present invention, in which one or more metal pins 44 are arranged between the resonators 54 through the resonators 54, and both ends of the metal pins 44 are connected to the respective ground planes 4.

[Function] That is, the intra-resonator conductor layers 61, 62, and 64 are sandwiched between the two dielectric plates 21 to 24 and the dielectric plates 31 to 34 to form the triplate type dielectric filters 11 to 14. Therefore, within the range of the characteristics, the dielectric plates 21 to 2
4 and the dielectric plates 31 to 34 are the same, and this can be achieved by simply changing the shape of the intra-resonator conductor layers 61, 62, and 64, thereby making it possible to improve productivity.

In addition, the cycle time of the prototype is also shorter than the resonator conductor layer 61.62.6 compared to remaking the dielectric block of the conventional example described above.
4, the process can be sufficiently shortened, and many types can be easily created with high accuracy.

Here, the TEM mode resonator has a resonant impedance Z0, as shown in the equivalent diagram of the TEM mode resonator in FIG.
A long resonator is shown with one end grounded and the other end open, and generally a fringing capacitor C (capacitance C shown) is inserted between the open end and the ground.
This will shorten the length of the resonator a little.

This relational condition is expressed by the following equation.

L=λ/2π・tan-'1/Z, (+) smile, C
If C is decreased, L will approach λ/4, so if the resonance frequency is not changed, L will have to be lengthened, and conversely, if C increases, L can be reduced.

The present invention intentionally increases the number of fringing capacitors C to achieve miniaturization.

In the first invention, as shown in FIG. 1, the shape of the resonator internal conductor layer 61 is enlarged near the open end 65 to increase the area, and C is increased to shorten the length of the resonator 51. As a result, the length of one side of the dielectric plate 21.31 becomes shorter, and the size of the dielectric plate 21.31 can be reduced.

The second invention provides an open end 6 of the resonator 52, as shown in FIG.
A similar reduction in size can be achieved by making the ground plane 4 near 5 thicker by providing a recess 42 and partially approaching the ground plane 4 .

The third invention is similar to the second invention, as shown in FIG.
C is made thicker.

The fourth invention is to configure each resonator 54 in an interdigital manner, as shown in FIG. 4, to minimize the influence on the degree of coupling due to the widening of the internal conductor layer 64 near the open end 65 of the resonator 54. Furthermore, the coupling capacitance between the resonators 64 is reduced due to the metal pin 44 at ground potential inserted between them.
In order to achieve the same value, the spacing must be reduced, and as a result, the length of one side of the dielectric plate 24.degree. 34 becomes shorter, and the size can be reduced.

In this way, the influence of the dielectric portion on the electrical characteristics is small, and within the scope of the dielectric portion, it is made irrelevant, making it possible to provide a small and low-cost dielectric filter.

〔Example〕

The present invention will be specifically described below with reference to embodiments shown in the drawings. The same reference numerals indicate the same objects throughout the figures. FIG. 1 is a configuration diagram of an embodiment of the first invention, FIG. 2 is a configuration diagram of an embodiment of the second invention, and FIG. 3 is a configuration diagram of an embodiment of the third invention.
FIG. 4 shows a configuration diagram of an embodiment of the fourth invention.

This example is applied to a dielectric filter used in the 800 MHz band of mobile radio, in which two dielectric plates of the same shape are brought into close contact, the outer surface is used as the grounding surface of the conductive layer, and the contact surface is made of copper. This is a triplate type dielectric filter in which a plurality of 72M mode resonators are configured and coupled by arranging a thin internal resonator conductor layer.

The embodiment of the first invention is as shown in FIG.
On both sides, L-shaped input terminals 71 and output terminals 72 for magnetic field coupling are disposed at a predetermined interval in a comb shape with one end connected in common, and the other end of the resonator 51 is an open end. It's 65.

The dielectric plate 21.31 is made of a titanate barum porcelain material with a high dielectric constant, and has a rectangular shape of 30 m in width x 15 m in height x 3 m in thickness, and is metallized on the entire surface except for the adhesive surface to form the ground plane 4 of the conductor layer. In addition, the horizontal edge of the adhesive surface is metalized to have the same width as the common connection part of the intra-resonator conductor layer 61 to provide a grounding part 46, and the corner facing the grounding part 46 on the same surface is also metalized. A bonding allowance 47 is provided, each of which is connected to the other ground surface 4.
It is conductive.

Each of these resonators 51 has a shape in which the vicinity of the open end 65 of the intra-resonator conductor layer 61 is expanded into a rectangular shape, and the number of fringing capacitors is increased to shorten the length of the resonator 51. The height dimension of the plate 21.31 is reduced.

As for assembly, the common connection part of the intra-resonator conductor layer 61 is stacked on the ground part 46 of the adhesive surface of the dielectric plate 21.31, and the soldering is sandwiched together. At this time, the adhesion margins 47 on the same surface are also soldered to each other to firmly assemble the whole.

Of course, the input terminal 71 and the output terminal 72 protrude from the seam, and the nearby ground plane 4 is avoided so as not to come into contact with them.

In this dielectric filter 11, an input is applied from an external circuit to an input terminal 71, and the first resonator 51 of 72M mode is excited by magnetic field coupling. 51 is excited, the third resonator 51 is further excited at the resonant frequency, the resonator frequency is selected, and the output is led to the external circuit from the output terminal 72 which is similarly magnetically coupled, and the filter characteristics are changed. can get.

The embodiment of the second invention is as shown in FIG.
Three resonators 52 are formed on a mm W4 plate, and L-shaped input terminals 71 and output terminals 72 for magnetic field coupling are disposed on both sides at a predetermined interval in a comb shape with one end commonly connected. Resonator 5
The other end of 2 is an open end 65.

The dielectric plates 22 and 32 also have the same dimensions and dimensions as those of the first invention, and similarly have a ground surface 4 on the outer surface and a ground portion 46 on the adhesive surface.
, an adhesive allowance 47 is provided.

However, in order to increase the fringing capacitor at the open end 65 of the resonator 52, a circular hole-shaped recess 42 is provided in the opposing portion so as to bring the ground plane 4 near the open end 65 closer together.

Assembly and operation are completely the same as those of the first invention.

The embodiment of the third invention is as shown in FIG. 3, and the intra-resonator conductor layer 62 is the same as that of the second invention.

The dielectric plates 23, 33 are also the same as those of the second invention, but the method of increasing the fringing capacitors is different, and instead of the recess 42, a groove 43 is provided to bring the ground plane 4 closer.

Assembly and operation are completely the same as those of the first invention.

The embodiment of the fourth invention is as shown in FIG. 4, in which three resonators 54 are arranged in an interdigital manner.

For this reason, in the intra-resonator conductor layer 64, the resonator 54, which is shortened by expanding the vicinity of the open end 65, is arranged by alternating the directions vertically. It has a shape in which both sides are bordered and connected so that they are integrally formed.

The dielectric plates 24 and 34 have the same size and shape as those of the first invention, and similarly have a ground surface 4 on the outer surface, a ground portion 46 on the upper and lower edges on the adhesive surface, and a thin adhesive margin connecting the ground portions 46 on both sides. 48 is the provision.

Moreover, the entire circumference of the intra-resonator conductor layer 64 is edged,
Since the input/output terminals 71 and 72 were not provided on the same surface, the ground plane 4 of the dielectric plate 24 at the corresponding position of the first and third resonators 54 was cut out to form the input cover pattern 73 for electric field coupling. An output cover turn 74 is provided insulated.

Furthermore, a metal pin 4 made of copper wire is placed at the center position between each resonator 54.
A through hole 49 for arranging the hole 4 is bored.

For assembly, similarly, the resonator internal conductor layer 64 is sandwiched between the dielectric plates 24 and 34, the ground portion 46 and the adhesive portion 48 are fixed by soldering, and the two metal pins 44 are inserted into each through hole. 49 and fix both ends to the ground plane 4 by soldering.

By inserting this metal pin 44, the coupling between each resonator 54 is weakened, so in order to obtain the same coupling as before, it is necessary to shorten the spacing. It is the smallest compared to the previous model, and the external size can be made smaller.

The above embodiments are merely examples, and the shapes and dimensions of each part, the number of resonators, and the input/output coupling method are not limited to those described above.

The enlarged shape near the open end 65 of the resonator 51 may be circular or polygonal in addition to a square.

In addition, the recesses 42 provided in the dielectric plates 22 and 32 are also circular holes.
It may be a square hole or a triangular hole, and it may be provided on one side instead of both sides.

In addition, the groove portion 43 provided in the dielectric plate 23.33 may also be a round groove, a triangular groove, or a stepped surface in addition to the square groove (and
There is no problem even if it is provided on only one side.

Although this embodiment is for mobile radio use in the 800 MHz band, the applicable frequency band is not limited to this.

[Effects of the Invention] As described above, according to the present invention, the influence of the dielectric portion on the electrical characteristics can be suppressed to a minimum and it can be made irrelevant.
Furthermore, a small and low-cost dielectric filter can be obtained, and productivity can be greatly improved.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the first invention, Fig. 2 is a block diagram of an embodiment of the second invention, Fig. 3 is a block diagram of an embodiment of the third invention, and Fig. 4 is a block diagram of an embodiment of the third invention. 4 is a block diagram of an embodiment of the invention, FIG. 4 is a conventional example, and FIG. 6 is an equivalent diagram of a TEM mode resonator. In the figure, 4.94 is the ground plane, 11, 12.13.14.91 is the dielectric filter, 21
~24. 31 to 34 are dielectric plates, 42 is a recess, 43 is a groove, 44 is a metal pin, 46 is a ground portion, 47.48 is an adhesive margin, 49 is a through hole, 51 to 54.95 are resonators, 61, 62, 64 are internal conductor layers of the resonator, 65.96 is an open end, 71 is an input terminal, 72 is an output terminal, 73 is an input cover turn, 74 is an output cover turn, 92 is a dielectric block, 93 is one side, 97 is a combination pattern. Dielectric material photograph; 1: Mi-TEN five-domain device/) Ear value diagram 5th side Conventional example 16 Figure 22-

Claims (4)

[Claims] (1) Two dielectric plates (21) and (31) having the same external shape are brought into close contact with each other, the outer surface is used as the grounding surface of the conductor layer (4), and the internal conductor layer (61) in the resonator is placed on the contact surface. A triplate type dielectric filter (11) configured with a TEM mode resonator (51), comprising an intra-resonator conductor layer (61) near the open end (65) of the resonator 6 (51). A dielectric filter characterized by being partially enlarged. (2) Two dielectric plates (22) and (32) having the same external shape are brought into close contact with each other, the outer surface is used as the grounding surface of the conductor layer (4), and the internal conductor layer (62) in the resonator is placed on the contact surface. A triplate dielectric filter (12) comprising a TEM mode resonator (52), the dielectric plate (12) facing near the open end (65) of the intra-resonator conductor layer (62). 22) A dielectric filter characterized in that the ground plane (4) of (32) is brought close to a predetermined position by partially providing a recess (42). (3) Two dielectric plates (23) and (33) having the same external shape are brought into close contact with each other, the outer surface is used as the grounding surface (4) of the conductive layer, and the internal conductor layer (62) in the resonator is arranged on the closely joined surface. A triplate dielectric filter (13) comprising a TEM mode resonator (53), the dielectric plate (13) facing near the open end (65) of the intra-resonator conductor layer (62). 23) A dielectric filter characterized in that the ground plane (4) of (33) is brought close to a predetermined position by partially providing a groove (43). (4) Two dielectric plates (24) and (34) having the same external shape are brought into close contact with each other, the outer surface is used as the grounding surface (4) of the conductive layer, and the internal conductor layer (64) in the resonator is placed on the closely joined surface. A triplate type dielectric filter (14) configured with a TEM mode resonator (54), which is an interdigital type in which a plurality of the resonators (54) are arranged with open ends (65) arranged in alternating directions. The resonator (54) is constructed by penetrating the two dielectric plates (24) and (34).
) A dielectric filter characterized in that one or more metal pins (44) are arranged between the metal pins (44), and both ends of the metal pins (44) are connected to respective ground planes (4).