KR20020095211A - Dielectric filter, antenna duplexer - Google Patents

Abstract

A dielectric filter includes resonator electrodes, an inter-stage coupling capacitor electrode, and an input/output coupling capacitor electrode on dielectric substrates, respectively. The resonator electrodes are electro-magnetically coupled to each other to form a tri-plate structure, are made of a metallic foil embedded in a resonator dielectric substrate. Another dielectric filter includes an upper shield electrode dielectric substrate, an inter-stage coupling capacitor dielectric substrate, a resonator dielectric substrate, and an input/output coupling capacitor dielectric substrate which are made of a composite dielectric material including a high-dielectric- constant material and a low-dielectric-constant material. The above described arrangement provides the dielectric filter with an improved Q factor of a resonator, a low loss, and a high attenuation.

Description

Dielectric filter and antenna common device and communication device using it {DIELECTRIC FILTER, ANTENNA DUPLEXER}

In recent years, dielectric filters have been used as high frequency filters in mobile phones, and in particular, it is desired to reduce their size and thickness. Currently, attention is focused on planar stacked dielectric filters instead of coaxial filters. A conventional planar stacked dielectric filter is described with reference to the associated drawings.

17 is an exploded perspective view of a conventional planar stacked dielectric filter. The dielectric filter having the laminated structure shown includes six dielectric substrates 1a to 1f. The shield electrode 2a is formed on the upper surface of the dielectric substrate 1b. An end-to-end coupling capacitor electrode 3 is formed on the upper surface of the dielectric substrate 1c. Resonator electrodes 4a and 4b are formed on the upper surface of the dielectric substrate 1d. Input and output coupling capacitor electrodes 5a and 5b are formed on the upper surface of the dielectric substrate 1e. The shield electrode 2b is formed on the upper surface of the dielectric substrate 1f.

On both left and right sides, cross-sectional electrodes 6a and 6b are formed as ground ports, respectively. On the back side, a cross-sectional electrode 7 is formed as a ground port connected to the open ends of the shield electrodes 2a and 2b and the resonator electrodes 4a and 4b, respectively. One end of the end face electrode 8 provided on the front side of the dielectric substrate stack structure is connected to each short end of the resonator electrodes 4a and 4b, and the other end is connected to the shield electrodes 2a and 2b. On the left and right sides of the laminated dielectric substrate, the end faces electrodes 9a and 9b are connected to the input / output coupling electrodes 5a and 5b, respectively, and operate as input / output ports.

The resonator electrodes, the end-to-end coupling capacitor electrodes, and the input / output coupling capacitor electrodes of the planar multilayer dielectric filter are manufactured by pattern printing of the conductive paste, so that it is difficult to have a uniform thickness.

FIG. 18 is a cross-sectional view of the dielectric substrates 1c and 1d shown in FIG. As shown, the resonator electrodes 4a and 4b have a thick central portion and become thinner toward the ends. When the dielectric substrate is laminated, the electrode provided by printing will have its end pointed. At both ends, a high frequency current is concentrated. For this reason, the Q value of the resonator electrode is reduced, thereby degrading the performance of the filter. The electrically conductive paste which mainly contains a metal powder reduces the performance of a filter by having a undulating surface resulting from screen printing mesh at the time of screen printing.

The resonator electrodes, the end-to-end coupling capacitor electrodes, and the input / output coupling capacitor electrodes of the planar stacked dielectric filter are provided on each surface of the ceramic substrate of the same material having the same dielectric constant. Thus, since the current of the resonator, which is an important component of the dielectric filter, concentrates at each end of the resonator electrodes 4a and 4b, the current increases the conductor loss, thereby degrading the Q value of the resonator and the performance of the dielectric filter.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter for a high frequency wireless device such as a cellular phone. In particular, the present invention provides strip-line resonator electrodes provided on a dielectric substrate to be electromagnetically coupled to each other to provide electrons to each other. A dielectric filter coupled systematically.

1 is an exploded perspective view of a dielectric filter according to a first embodiment of the present invention;

FIG. 2A is a cross-sectional view of the dielectric substrate laminated structure at line 2A-2A in FIG. 1;

2b is an enlarged cross-sectional view of the resonator electrode,

2C is a perspective view of a resonator dielectric substrate comprising a resonator electrode provided with a wide portion;

3A to 3F are views showing the manufacturing procedure of the dielectric filter according to the second embodiment of the present invention;

4A and 4B show a manufacturing procedure of the dielectric filter according to Example 2;

5A to 5F are views showing a manufacturing procedure of the dielectric filter according to the third embodiment of the present invention;

6A to 6D are views showing the manufacturing procedure of the dielectric filter according to the fourth embodiment of the present invention;

7 is a schematic block diagram of a communication device including an antenna common according to Embodiment 5 of the present invention;

8 is a sectional view of a dielectric filter according to a sixth embodiment of the present invention;

9A to 9C are views showing a manufacturing procedure of the dielectric filter according to the seventh embodiment of the present invention;

10A to 10C are views showing a manufacturing procedure of the dielectric filter according to the seventh embodiment;

11 is a sectional view of a dielectric filter according to Embodiment 8 of the present invention;

12 is a sectional view of a dielectric filter according to a ninth embodiment of the present invention;

13 is a sectional view of a dielectric filter according to a tenth embodiment of the present invention;

14A and 14B schematically show a profile of a current of an electrode of a conventional filter, and a profile of a current of an electrode of a filter according to an embodiment;

15 is a plan view showing the shape of resonator electrodes according to Embodiment 11 of the present invention;

16 is a block diagram of a communication device including an antenna common device according to a twelfth embodiment of the present invention;

17 is an enlarged perspective view of a conventional dielectric filter;

18 is a cross-sectional view of a resonator electrode provided in a conventional dielectric filter.

The dielectric filter includes resonator electrodes formed of a metal foil and electromagnetically coupled to each other, end-to-end coupling capacitor electrodes for coupling the resonator electrodes, input / output coupling capacitor electrodes for inputting and outputting signals to the resonator electrodes, and the resonator electrodes. And dielectric substrates provided with the end-to-end coupling capacitor electrode and the input / output coupling capacitor electrode. In this filter, each resonator electrode has a uniform thickness, thereby providing high Q value, low loss, and high attenuation of the resonator.

(Example 1)

1 is an exploded perspective view of a dielectric filter according to a first embodiment of the present invention. The dielectric filter having the same basic arrangement as that shown in FIG. 17 includes six dielectric substrates 11a to 11f. The resonator dielectric substrate 11d including the resonator electrodes is a ceramic substrate having a high dielectric constant, but may be a resin substrate or a resin composite substrate containing a resin material and an inorganic filler.

The shield electrode dielectric substrate 11b includes a shield electrode 12a on its upper surface. The end-to-end coupling capacitor dielectric substrate 11c has an end-to-end coupling capacitor electrode 13 on its upper surface. The resonator dielectric substrate 11d includes resonator electrodes 14a and 14b formed of foil containing gold, silver, or copper having a thickness in the upper surface thereof in the range of 10 μm to 400 μm. Each resonator electrode has a cross section in which four corners are rounded. The input / output coupling capacitor dielectric substrate 11e includes input / output coupling capacitor electrodes 15a and 15b on an upper surface thereof. The shield electrode dielectric substrate 11f includes a shield electrode 12b on its upper surface. Dielectric substrates 11a to 11f are stacked together in a layer structure to form a dielectric filter.

Similar to conventional filters, cross-sectional electrodes 16a and 16b are provided on both left and right sides thereof. Single-sided electrodes 19a and 19b are provided as input / output ports on both the left and right sides thereof, and are connected to the input / output coupling capacitor electrodes 15a and 15b, respectively. Single-sided electrodes 17 and 18 are provided on the back and front side of the laminated dielectric substrate.

The characteristic of the filter according to this embodiment is in the arrangement of the resonator electrodes. The resonator electrodes 14a and 14b are formed of metal foil containing gold, silver or copper on the upper surface of the resonator dielectric substrate 11d as shown in FIG.

FIG. 2A is a cross-sectional view of the dielectric substrates 11c, 11d, and 11e at the line 2A-2A in FIG. 1. On the upper surface of the resonator dielectric substrate 11d, resonator electrodes 14a and 14b made of metal foil containing gold, silver or copper are placed, and the manufacturing method thereof will be described later in more detail. In addition, the end-to-end coupling capacitor electrode 13 and the input / output coupling capacitor electrodes 15a and 15b are respectively provided by pattern printing of conductive paste on the upper surfaces of the end-to-end coupling capacitor dielectric substrate 11c and the input / output coupling capacitor dielectric substrate 11e. have. The inter-phase coupling capacitor electrode 13 and the input / output coupling capacitor electrodes 15a and 15b may be formed of the same metal foil as the resonator electrodes 14a and 14b.

Each of the resonator electrodes 14a and 14b of this embodiment will have a cross section of rounded corners and rounded ends to improve electrical performance. Rounded corners and ends will have a radius of at least 1 μm. The resonator electrodes 14a and 14b have a rounded corner rectangular cross section that can be formed into strips of the electrical electrode frame to a desired electrode size by chemical etching or electropolishing. More preferably, the resonator electrodes 14a and 14b may be surface polished or metal plated to have a smooth surface having a roughness in the range of 0.5 μm to 0.01 μm.

The resonator electrodes 14a and 14b, when formed from a metal foil having a smooth surface, form a resonator having an improved Q value, thereby contributing to the low loss and better attenuation characteristics of the dielectric filter.

The resonator electrodes 14a and 14b are not limited to the shape of the uniform width strip as shown in Fig. 1, but T having a wide portion 14aw or 14bw as shown in Fig. 2c according to the required characteristics. It may be arranged in a shape.

According to this embodiment, the filter comprises a strip electrode of metal foil having a thickness in the range of 10 μm to 400 μm. In a dielectric filter operating at a high frequency, the high frequency current will be concentrated in an area close to the surface of the electrode without uniformly flowing in the thickness direction of the electrode. The conductor of the resonator has a thickness larger than the thickness of this region and the surface thickness. The strip electrode in which the high frequency current flows along the upper and lower surfaces has twice the thickness of the conductor. Therefore, when the surface depth is in the range of approximately 1 µm to 3 µm at a frequency of kHz, the metal foil preferably has a thickness of 10 µm or more that is greater than twice its depth. Experiments have shown that the resonator is high until it has a thickness of 100 μm, but has a Q value which is unchanged or very small from the thickness of 200 μm. The dielectric filter thickens as it includes a strip that thickens. According to the above, it will be preferable that the metal foil has a thickness of 400 μm or less.

The metal foil of the electrodes of the resonator containing copper and silver of 100 μm gave a Q value of 280. The resonator electrodes formed by the known 40 μm thick printing method provide a Q value of 240. Therefore, the resonator electrodes of the metal foil of this embodiment provide the improved Q value to the resonator.

(Example 2)

3A to 3F show a method of manufacturing the resonator dielectric substrate 27, which is an important component of the dielectric filter according to the second embodiment of the present invention.

3A is a cross-sectional view of the substrate at line 3A-3A in the plan view of FIG. 3B. On both upper and lower surfaces of the metal foil 21 containing gold, silver, or copper, an etching resist layer 22 of the same pattern is provided by lithography. The metal foil 21 is completed as an electrode frame 24 having resonator electrodes 23 as shown in FIG. 3B when the surface is polished by chemical or electrolytic treatment after being etched from both sides. The electrode frame 24 includes positioning guides 25 on both inner sides thereof. The electrode frame 24 may be manufactured by mold molding.

3C shows a cross section of the electrode frame 24. The electrode frame 24 is then placed on the dielectric sheet 26 and pressed together up, down, left, and right as indicated by the arrows in FIG. 3D. As a result shown in FIG. 3E, the electrode frame 24 is embedded in the dielectric sheet 26. This sheet is then divided into resonator dielectric substrates 27, as shown in FIG. 3F.

4A and 4B show the procedure for manufacturing the dielectric filter by the resonator dielectric substrate 27 (same as the substrate 11d shown in FIG. 1) having the resonator electrodes 14a and 14b of the metal foil. In this procedure, the same components as those shown in Fig. 1 are denoted by the same reference numerals and described.

In Fig. 4A, a protective ceramic dielectric substrate 11a as a protective layer, a shield electrode ceramic dielectric substrate 11b having a shield electrode 12a, an end-to-end coupling capacitor ceramic dielectric substrate 11c having an end-to-end coupling capacitor electrode 13, An input / output coupling capacitor ceramic dielectric substrate having a resonator ceramic dielectric substrate 11d having resonator electrodes 14a and 14b of a metal foil filled and embedded by the procedures of FIGS. 3A to 3F, and input / output coupling capacitor electrodes 15a and 15b ( 11e) and the shield electrode ceramic dielectric substrate 11f having the shield electrode 12b are sequentially stacked and pressed together in the direction indicated by the arrow. This provides the dielectric substrate assembly 28 shown in FIG. 4B. The dielectric substrate assembly 28 is fired in a reducing atmosphere at 900 ° C to obtain a laminated ceramic dielectric filter.

According to this embodiment, each dielectric ceramic substrate having a high dielectric constant is a Bi-Ca-Nb-O-based, Ba-Ti-O-based, [Zr (Mg, Zn, Nb)] TiO ₄ + MnO ₂ -based, and The Ba-Nd-Ti-O mixture may be formed of a dielectric material. The part which constitutes no capacity may be formed of forsterite or alumina borosilicate glass.

(Example 3)

Example 3 differs from Example 2 in that the dielectric substrate including the resonator electrode of the metal foil to be embedded is formed of a composite material containing a thermosetting resin such as an epoxy resin and an inorganic filler of powder of Al ₂ O ₃ or MgO.

The thermosetting resin of the composite material may be formed of not only an epoxy resin but also a phenol resin and a cyanate resin.

5A to 5F are schematic diagrams essentially illustrating the method according to the present embodiment. As shown in Fig. 5A, a protective ceramic dielectric substrate 31a as a protective layer in the form of a green sheet, a shield electrode ceramic dielectric substrate 31b in the form of a green sheet having a shield electrode 32a, and an inter-coupled capacitor electrode ( The end-to-end coupling capacitor ceramic dielectric substrate 31c in the form of a green sheet having 33) is laminated and pressed together in the direction indicated by the arrow. The stacked substrate is then fired at approximately 900 ° C. to form the first dielectric block 34 shown in FIG. 5B. Next, as shown in FIG. 5C, the green sheet type shield electrode ceramic having the input / output coupling capacitor ceramic dielectric substrate 36 in the form of a green sheet having the input / output coupling capacitor electrodes 35a and 35b and the shield electrode 32b. The dielectric substrate 37 is laminated and pressed. The laminated substrate is then fired at approximately 900 ° C. to form the second dielectric block 38 shown in FIG. 5D.

Next, a resonator composite dielectric substrate 40 fabricated by the process described in FIGS. 3A-3F and having embedded resonator electrodes 39a and 39b is shown in FIG. 5E as shown in FIG. 5E. And the second dielectric block 38 are pressed together in the direction indicated by the arrow. The substrate 40 includes input / output coupling capacitor electrodes 35a and 35b embedded in the bottom surface thereof. The substrate is heated at a temperature in the range of 150 to 200 ° C. to cure the composite material, thereby joining the first dielectric block 34, the resonator composite dielectric substrate 40, and the second dielectric block 38 together in FIG. 5F. Provided is the dielectric filter shown.

In order to improve the performance of the filter, the resonator composite dielectric substrate 40 is made of Al ₂ O ₃ and MgO, as well as Bi-Ca-Nb-O, Ba-Ti-O, [Zr (Mg, Zn, Nb)] TiO _4. It can contain a high content of dielectric ceramic powder with high dielectric constant as an inorganic filler selected from + MnO ₂ , and Ba-Nd-Ti-O mixtures.

Since the resonator electrodes 39a and 39b of the metal foil of this embodiment are embedded in the composite substrate containing the resin, the dielectric filter is made to be manufactured by the simple process shown in Figs. 5A to 5F.

It is preferable that the inorganic filler of the composite material of this embodiment contains approximately 70% to 90% of the composite material to have the same thermal expansion as that of the ceramic material.

In order to increase the dielectric constant of the composite material, more filler may be contained. For adhesive strength, the filler may contain less than the above range.

The resonator significantly increases the Q value by the electrode of the metal foil having the high conductor Q value and the dielectric substrate having the high material Q value.

The dielectric filter of the third embodiment is characterized by the resonator electrodes 39a and 39b embedded in a dielectric material having a low dielectric constant. Each electrode is in contact with a material having a high dielectric constant at its upper and lower surfaces, and a material having a high dielectric constant at both sides thereof.

The dielectric filter of Example 3 has an electrode such as a capacitor coupled electrode or an input / output electrode in a high dielectric constant material, but has the same advantages even if the high dielectric constant material does not include an electrode. To include the electrode, the dielectric material is fired with the electrode. However, dielectric materials, i.e. low temperature co-fired ceramics (LTCC), which can be fired with the electrodes, have an almost low Q value (material Q value). According to the fourth embodiment, the resonator electrode has a high Q value by being placed in direct contact with a high temperature calcined ceramic which has a high Q value but cannot be fired with the electrode. The dielectric material, when not including an electrode, provides the dielectric filter with the advantages of HTCC, that is, a high material Q value.

(Example 4)

The dielectric filter according to Example 4 of the present invention is manufactured by the following method. As shown in FIG. 6A, the electrode frame 24 fabricated in the manner shown in FIGS. 3A-3F is pressed onto a composite material 41 having the same thickness as the electrode frame 24. As a result shown in FIG. 6B, the gap portion 42 of the electrode frame 24 is filled with the composite material 41 to form the electrode composite substrate 43.

Next, a dielectric substrate 44 of ceramic material in the form of a green sheet having a high dielectric constant is positioned on the top surface of the second dielectric block 38 in the form of a green sheet manufactured in the manner shown in FIG. 5C. It is fired under the same conditions as to form the third dielectric block 45. As shown in FIG. 6C, a resonator composite dielectric substrate 46 separated from the electrode composite substrate 43 between the first dielectric block 34 and the third dielectric block 45 fabricated in the manner shown in FIG. 5B. This is located. These are then pressed together to form the dielectric filter shown in FIG. 6D. This filter includes a dielectric substrate 44 having a high dielectric constant located between the input / output coupling capacitor electrodes 35a and 35b and the resonator electrodes 39a and 39b, thereby having an improved Q value even when manufactured in an inexpensive process. . This resonator significantly increases the Q value by the electrode of the metal foil having the high conductor Q value and the dielectric substrate having the high material Q value.

The dielectric filter of Embodiment 4 is characterized by resonator electrodes 39a and 39b embedded in a dielectric material having a low dielectric constant. Each electrode is in contact with a material having a high dielectric constant at its upper and lower surfaces, and a material having a high dielectric constant at both sides thereof.

Instead of the composite substrate 43, the filter of this embodiment provides the resonator electrodes 39a and 39b directly on the upper surface of the third dielectric block 45 in the process shown in FIG. 6C, and the electrode frame 24. The gap portion 42 is made by filling a liquid resin such as epoxy, phenol, cyanate, polyphenylene phthalate, or polyphenylene ether resin with an adhesive, and then joining the dielectric block 34 from the above. You may be. These may be joined by a paste of glass flit instead of a resin adhesive, whereby the gap portion 42 of the electrode frame 24 is filled, fired at about 900 ° C, and glass sealed.

In the processes shown in FIGS. 3A to 3E, 6A, and 6B, a plurality of resonator electrodes are simultaneously obtained in the electrode frame. In other processes, each dielectric filter is described for convenience of explanation.

The resonator electrodes of the metal foils of the above-described embodiments have an average surface roughness in the range of 0.5 to 0.01 mu m as the surface is polished or metal plated by Au, Ag, or Cu. Since the resonator electrode has a smoother surface than the electrode produced by the conventional conductive paste printing process that provides an average surface roughness in the range of 1 to 3 mu m, it has an increased Q value, thereby improving the performance of the filter. .

The dielectric filter of Example 4 has an electrode such as a capacitor coupled electrode or an input / output electrode in a high dielectric constant material, but has the same advantages even if the high dielectric constant material does not include an electrode. To include the electrode, the dielectric material is fired with the electrode. However, the dielectric material, i.e., low temperature cofired ceramic (LTCC), which can be fired with the electrode, has an almost low Q value (material Q value). According to the fourth embodiment, the resonator electrode has a high Q value by being placed in direct contact with a high temperature calcined ceramic which cannot be fired together with the electrode. The dielectric material, when not including an electrode, provides the dielectric filter with the advantages of HTTC, that is, a high material Q value.

The resonator of Example 4 includes a pair of resonator electrodes of metal foil, but providing three or more resonator electrodes provides the same effect to the filter.

The resonator electrode formed by pattern printing of the conventional electrically conductive paste has a limit in thickness. The resonator electrode of this embodiment formed of the metal foil can be manufactured by a hotolithographic process and an etching process, so that the conductor loss is reduced with a desired thickness according to desired characteristics. Because of the filter with this electrode, the communication device can be miniaturized and the performance can be improved.

(Example 5)

This embodiment includes the dielectric filters of Embodiments 1 to 4 as transmitter filter 62 or receiver filter 61 for separating the signal into a received signal and a transmitted signal in a communication device 67 such as a cellular phone. It relates to an antenna common (65). As shown in FIG. 7, the dielectric filters of the above-described embodiment are connected to both ends of the matching circuit 266 having the antenna port 63 connected to the antenna 64. For this reason, a coaxial resonator commonly used for a conventional antenna common device and occupying a large space can be excluded. The antenna common of this embodiment reduces the overall dimension.

Since the antenna common device of the present embodiment includes a dielectric filter having a resonator electrode formed of a metal foil, it can contribute to miniaturization and performance improvement of a communication device such as a cellular phone.

The resonator electrode of the dielectric filter in the antenna common device has a high Q value because the surface is smoothed by polishing or metal plating.

In the antenna common device, the resonator electrode of the dielectric filter is subjected to photomasking and etching of both surfaces of a metal foil sheet containing gold, silver, or copper, followed by a step of rounding its ends and corners by chemical or electrolytic polishing. It is made of the formed electrode frame. As a result, the resonator electrode may have rounded ends and corners.

(Example 6)

8 is a sectional view of a dielectric filter according to a sixth embodiment of the present invention. The dielectric filter having a basic structure similar to that shown in FIG. 17 includes six dielectric substrates 111a to 111f.

The electrode of the dielectric filter may be made of the same conductive material as the conventional filter. Each electrode of the present embodiment has a rectangular cross section as shown in the cross-sectional view of FIG. 8 for convenience of description. The cross section may be any suitable shape, such as the bobbin shape shown in FIG. 18, and may be provided by pattern printing of the conductive paste.

The upper shield electrode dielectric substrate 111b includes a shield electrode 112a on an upper surface thereof. The end-to-end coupling capacitor dielectric substrate 111c includes an end-to-end coupling capacitor electrode 113 on an upper surface thereof. The resonator dielectric substrate 111d includes resonator electrodes 114a and 114b on its upper surface. The input / output coupling capacitor dielectric substrate 111e includes input / output coupling capacitor electrodes 115a and 115b on an upper surface thereof. The lower shield electrode dielectric substrate 111f includes a shield electrode 112b at an upper surface thereof. The substrates 111b to 111f are stacked together with the uppermost protective substrate 111a to provide the dielectric filter of this embodiment. The protective substrate 111a may be formed of a material other than the dielectric material, for example, an organic material capable of protecting the shield electrode from the surrounding environment.

The dielectric filter of this embodiment shown in FIG. 8 has cross-sectional electrodes on its left and right sides, as shown in FIG. 17, which is not shown and described.

The characteristic of the dielectric filter of this embodiment is in the structure of the substrate. As shown in FIG. 8, each of the upper shield electrode dielectric substrate 111b, the inter-coupled coupling capacitor dielectric substrate 111c, the resonator dielectric substrate 111d, and the input / output coupling capacitor dielectric substrate 111e has a high dielectric constant. A first dielectric material 116 (hereinafter referred to as a high dielectric constant material) and a second dielectric material 117 (hereinafter referred to as a low dielectric constant material) having a lower relative dielectric constant than the first dielectric material do. In particular, high dielectric constant materials and low dielectric constant materials are alternately arranged in the transverse direction.

Thus, high dielectric constant material 116 is located at the center of each resonator electrode 114a and 114b in the dielectric filter. Low dielectric constant material 117 is located outside of each resonator electrode 114a and 114b. This places the electric force lines uniformly on the resonator electrodes 114a and 114b. In the conventional dielectric filter, this line is distributed near each cross section of the electrode. Since the current densities of the resonator electrodes 114a and 114b are uniform, the conductor losses of the resonator electrodes 114a and 114b are reduced, thereby reducing the loss of the dielectric filter.

In the dielectric filter of this embodiment, each overlapping portion between the resonator electrodes 114a and 114b and the end coupling capacitor electrode 113 and each overlapping portion between the input / output coupling capacitor electrodes 115a and 115b and the end coupling capacitor electrode 113. It is filled with this low dielectric constant material 117. Because of this, the capacity and characteristics of the filter can be easily designed.

(Example 7)

9A to 9C show a manufacturing process of the composite ceramic dielectric substrate according to the seventh embodiment of the present invention. As shown in Fig. 9A, green sheets 121a and 121b formed of Bi-Ca-Nb-O ceramic material having high dielectric constant and green sheets 122a and 122b formed of forsterite ceramic material having low dielectric constant, and 122c) are alternately stacked. Each green sheet 121a and 122b includes ceramic green layers having a thickness of several micrometers to several hundred micrometers prepared by the doctor blade method of a slurry containing a powder of dielectric material and an organic binder.

The composite ceramic dielectric block 123 (hereinafter referred to as green sheet block) of the green sheets 121a and 122b is cut along lines A-A, B-B, C-C, and D-D as shown in FIG. 9B. This provides four composite ceramic dielectric green substrates 124-127 as shown in FIG. 9C. Each substrate comprises two different dielectric materials, a ceramic having a high relative dielectric constant and a ceramic having a low relative dielectric constant.

10A to 10C are perspective views showing the second half manufacturing process of the dielectric filter of this embodiment. As shown in FIG. 10A, an upper shield electrode 131a is provided on an upper surface of the ceramic dielectric green substrate 124. An upper end coupling capacitor electrode 132 is provided on the upper surface of the ceramic dielectric green substrate 125. The upper surface of the ceramic dielectric green substrate 126 is provided with resonator electrodes 133a and 133b having one end as a short end and the other end as an open end. Input and output coupling capacitor electrodes 134a and 134b are provided on an upper surface of the ceramic dielectric green substrate 127. Then, these are stacked together, and as shown in Fig. 10B, each of the upper side and the lower side thereof is provided with a ceramic dielectric green substrate having a protective ceramic green substrate 136 and a lower shield electrode 131b. 137). These are then pressed and fired to a predetermined temperature, providing the dielectric filter shown in FIG. 10C.

The ceramic dielectric green substrate 137 having the protective green substrate 136 and the lower shield electrode 131b shown in FIGS. 10A to 10C is formed of the same material as the ceramic material 122a having a low dielectric constant. These may be formed of a ceramic material having a high dielectric constant. The resonator electrode of the dielectric filter of this embodiment has one end as a short end and the other end as an open end, but may have both ends as an open end.

The ceramic dielectric green substrates 124, 125, 126, and 127 of this embodiment shown in Figs. 9A to 9C and 10A to 10C are formed of green sheet blocks 123 and cut to desired thicknesses. The substrate may be formed from each green sheet block, each containing two different dielectric materials. The high dielectric constant portions of each ceramic dielectric green substrate may have different cross-sectional widths. For this reason, the dielectric filter can be designed flexibly.

The electrodes provided on the dielectric green substrate may be made by pattern printing of conductive paste or etching of metal foil. Ceramic dielectric green substrates with electrodes can be fired under desired conditions.

The first half procedure of Embodiment 7 in which the green sheet block 123 is divided into ceramic dielectric green substrates 124, 125, 126, and 127, and then an electrode is provided, stacked and fired is described. This procedure can be modified so that the ceramic dielectric green substrates 124, 125, 126, and 127 obtained from the green sheet block 123 are fired and then the electrode is provided. This deformation procedure prevents cracking of the substrate during firing.

The calcined ceramic dielectric substrate of the modifying procedure may be combined with an adhesive selected from thermosetting resins, composite materials containing thermosetting resins and inorganic fillers, glass frits having low melting temperatures, and the like.

As described, the characteristic of the dielectric filter of this embodiment is in laminated composite dielectric substrates formed of composite materials having different relative dielectric constants. Thus, the dielectric filter may include a substrate selected from a dielectric substrate having a single dielectric constant and a composite dielectric substrate depending on the desired shape and desired characteristics.

(Example 8)

Fig. 11 is a sectional view of the dielectric filter according to the eighth embodiment of the present invention. The dielectric filter of the eighth embodiment is modified by the structures of the end-to-end coupling capacitor electrodes 143 on the end-to-end coupling capacitor dielectric substrate 111c and the input / output coupling capacitor electrodes 145a and 145b on the input / output coupling capacitor dielectric substrate 111e. Different from 6. As shown in FIG. 11, both ends of the end-to-end coupling capacitor electrode 143 and one end of each input / output coupling capacitor electrode 145a and 145b are located in the high dielectric constant material 116. Because of this structure, the capacitor portion having the capacitance is located in the high dielectric constant material, thereby increasing the capacitance of the capacitor portion of the dielectric filter.

(Example 9)

FIG. 12 shows a ninth embodiment of the present invention featuring dielectric substrates 111a through 111f having a tri-plate structure formed of a composite material comprising a high dielectric constant material 116 and a low dielectric constant material 117. The dielectric filter by this is shown. Dielectric substrates are made of a cut green sheet block, and thus are manufactured in a simple procedure.

(Example 10)

Fig. 13 shows the dielectric filter of embodiment 10 of the present invention. This filter includes a resonator dielectric substrate 111d and an inter-junction capacitor substrate 111c formed of a composite material comprising a high dielectric constant material 116 and a low dielectric constant material 117. The filter further includes a protective dielectric substrate 111a, an upper shield electrode dielectric substrate 111b, an input / output coupling capacitor dielectric substrate 111e, and a lower shield electrode dielectric substrate 111f formed of a low dielectric constant material 117. . This configuration of this embodiment suppresses problems such as cracks occurring after firing due to shrinkage differences between other dielectric materials as compared with the above-described embodiment in which all dielectric substrates are obtained from a single block.

14A and 14B show a current profile flowing through a conventional dielectric filter and a current profile flowing through the dielectric filter of the embodiments in the cross section of the resonator electrode. In a conventional dielectric filter, electric field lines normally biased to both sides of the resonator electrode embedded in a single dielectric material are uniformly aligned in the transverse direction by the configuration of this embodiment. Because of this, the current can flow uniformly through the cross section of the resonator electrode.

(Example 11)

The dielectric filter according to the eleventh embodiment of the present invention is almost the same as the above-described embodiments except for the configuration of the resonator electrode. The resonator electrode dielectric substrate is described with reference to the top view of FIG. 15, but other components are not described in greater detail.

The resonator electrode of the dielectric filter of the above-described embodiments has a rectangular shape of uniform width. The resonator electrodes 163a and 163b of this embodiment have wide portions 163aw and 163bw at their respective open ends as shown in FIG. The wide portions 163aw and 163bw are designed to determine the characteristics of the filter.

As shown in the drawings of this embodiment, each resonator electrode 163a and 163b has a central portion located on the high dielectric constant material and includes wide ends 163aw and 163bw located on the low dielectric constant material. Have This configuration provides the filter with the same advantages as the above-described embodiments.

In this embodiment, the filter includes two resonator electrodes, which may include three or more resonator electrodes having both ends and center portions respectively positioned in dielectric materials having different relative dielectric constants.

(Example 12)

Embodiment 12 of the present invention is the dielectric filter of Embodiments 6 to 11 as a transmitter filter 262 or a receiver filter 261 for separating signals into signals transmitted and signals received at a communication device 267 such as a cellular phone. An antenna common 265 having a. As shown in FIG. 16, antenna common 265 includes a dielectric filter of the foregoing embodiments connected to each of both ends of matching circuit 266 having antenna port 263 connected to antenna 264. As shown in FIG. . This configuration is commonly used in conventional antenna commoners and excludes coaxial resonators that occupy a large space. The antenna common of this embodiment reduces the overall dimension.

Since the antenna common device of the present embodiment includes a dielectric filter having a resonator electrode formed of a metal foil, it can contribute to miniaturization and performance improvement of a communication device such as a cellular phone.

The resonator electrodes, the end-to-end coupling capacitor electrodes, and the input / output coupling capacitor electrodes of this embodiment can be formed by pattern printing of a conductive paste containing gold, silver, or copper.

The resonator electrodes, the end-to-end coupling capacitor electrodes, and the input / output coupling capacitor electrodes of the present embodiment may be formed of a metal foil mainly containing gold, silver, or copper.

The first dielectric material is not limited to being formed of a Bi-Ca-Nb-O mixture, and may be selected from a group of ceramic materials including Ba-Ti-O and Zr (Mg, Zn, Nb) Ti-Mn-O. . The second dielectric material may be forsterite or alumina borosilicate glass-based ceramic material throughout the embodiments.

The dielectric filter of the embodiments is a ceramic material of Bi-Ca-Nb-O, Ba-Ti-O, or Zr (Mg, Zn, Nb) Ti-Mn-O as the first dielectric material and a polyester as the second dielectric material. By including the ceramic material of light or alumina borosilicate glass, operation reliability and material properties are improved.

The dielectric filter may be manufactured by the following process.

(a) combining a first dielectric material in the form of a green sheet and a second dielectric material in the form of a green sheet having a lower permittivity than the first dielectric material in a lateral direction to provide a composite ceramic dielectric block of the green sheet;

(b) cross cutting the composite ceramic dielectric block in the form of a green sheet to provide a composite dielectric substrate in the form of a green sheet comprising a first dielectric material and a second dielectric material;

(c) providing, on each top surface of the composite dielectric substrates in the form of a green sheet, an upper shield electrode, an end-to-end coupling capacitor electrode, a resonator electrode, and an input / output coupling capacitor electrode, and then stacking the composite dielectric substrate under specific conditions. Fire them.

Because of these processes, dielectric substrates and electrodes can simply be fired simultaneously.

The dielectric filter of the present invention includes resonator electrodes formed of a metal foil having a uniform thickness, electromagnetically coupled to each other, and formed of a metal foil having a smooth surface. Thus, the filter is inexpensively manufactured, has an improved Q value, and has a low loss and a high attenuation.

Because of the dielectric filter of the present invention, a communication device such as a cellular phone including the filter can be miniaturized and improved in performance.

Claims (55)

In the dielectric filter, Resonator electrodes formed of metal foil and electromagnetically coupled to each other; An end coupling capacitor electrode for coupling the resonator electrodes; Input and output coupling capacitor electrodes for inputting and outputting signals to the resonator electrodes; And And dielectric substrates provided with the resonator electrodes, the end-to-end coupling capacitor electrodes, and the input / output coupling capacitor electrodes. The method of claim 1, The first dielectric substrate of the dielectric substrates provided with the resonator electrodes has a lower dielectric constant than the second dielectric substrate of the dielectric substrates, And the resonator electrodes have at least one side in contact with the second dielectric substrate. 3. The dielectric filter of claim 2, wherein the resonator electrodes each have a side contacting the first dielectric substrate. The dielectric filter of claim 1, wherein each of the resonator electrodes has a short end at one end and an open end at the other end. 5. The dielectric filter of claim 4, wherein the resonator electrodes each have a wide portion at its open end. The dielectric filter of claim 1, wherein the resonator electrodes have open ends at both ends thereof. 7. The dielectric filter of claim 6, wherein the resonator electrodes each have at least one wide portion provided at its open end. The dielectric filter according to claim 1, wherein the metal foil contains at least one of gold, silver, and copper. The dielectric filter of claim 1, wherein the resonator electrodes have a cross section each having an arc shape and a rounded square shape. The dielectric filter of claim 1, wherein the resonator electrodes have respective thicknesses ranging from 10 μm to 400 μm. The dielectric filter of claim 1, wherein the resonator electrodes have respective surfaces polished or metal plated. The dielectric filter of claim 1, wherein the resonator electrodes have respective average surface roughness in the range of 0.5 μm to 0.01 μm. In the method for producing a dielectric filter, Providing resonator electrodes of a metal foil; Embedding the resonator electrodes in a dielectric substrate to form a resonator dielectric substrate; And Stacking said resonator dielectric substrate with another dielectric substrate having a conductive layer on a surface thereof to form a laminated dielectric substrate. The method of manufacturing a dielectric filter according to claim 13, wherein the metal foil contains at least one of gold, silver, and copper. The method of claim 13, wherein providing the resonator electrodes comprises: Providing photomasks on both sides of the metal foil; Etching the metal foil through the photomask; And And forming an electrode frame by processing the cross-sectional shape of the etched metal foil to have a rounded rectangular shape or an arc shape by chemical or electropolishing. The method of claim 13, wherein providing the resonator electrodes comprises: Embedding the resonator electrodes in a resonator ceramic dielectric substrate in the form of a green sheet. The method of claim 13, wherein forming the multilayer dielectric substrate comprises: Stacking a resonator ceramic dielectric substrate in the form of a green sheet having the embedded resonator electrodes between the green dielectric sheet in the form of a green sheet having a conductive layer and the shield electrode ceramic dielectric substrate in the form of a green sheet; And Firing the stacked resonator ceramic dielectric substrate in the form of the green sheet, the laminated ceramic dielectric substrate in the form of the green sheet, and the shield electrode ceramic dielectric substrate in the form of the stacked green sheet. Manufacturing method. The method of claim 13, wherein the forming of the dielectric substrate comprises: Stacking a resonator ceramic dielectric substrate in the form of a green sheet with the buried resonator electrodes between the fired ceramic dielectric substrates; And Firing the stacked resonator ceramic dielectric substrate in the form of a green sheet. The method of claim 13, wherein providing the resonator electrodes comprises: Embedding the resonator electrodes in a resin substrate containing a thermosetting resin; And And heat-curing the resin substrate. 20. The method of claim 19, wherein the resin substrate is a composite substrate containing an amorphous filler. The method of claim 19, wherein forming the multilayer dielectric substrate comprises: Stacking the resin substrate and the shield electrode ceramic dielectric substrate. In antenna commons, An antenna port; A first filter comprising a dielectric filter according to any one of claims 1 to 12 and connected to the antenna port; And And a second filter coupled to the antenna port. In antenna commons, An antenna port; And An antenna common device comprising a dielectric filter according to any one of claims 1 to 12, each having a first and a second filter coupled to the antenna port. In antenna commons, An antenna port; A first transmitter filter comprising a dielectric filter manufactured by the method of any one of claims 13 to 21 and coupled to said antenna port; And And a second filter coupled to the antenna port. In antenna commons, An antenna port; And An antenna common device comprising a dielectric filter each produced by the method according to any one of claims 13 to 21, each having a first and a second filter coupled to said antenna port. A communication device comprising the antenna common device according to any one of claims 22 to 25. In the dielectric filter, At least one first, second, and third dielectric substrate comprising at least one remaining portion having a different relative dielectric constant and laminated together; Resonator electrodes on the first dielectric substrate, electromagnetically coupled to each other; An end-to-end coupling capacitor electrode on the second dielectric substrate for coupling the resonator electrodes; And And an input / output coupling capacitor electrode on a third dielectric substrate for inputting and outputting signals to the resonator electrodes. 28. The dielectric filter of claim 27, wherein each of the resonator electrodes has a short end at one end and an open end at the tartan. 29. The dielectric filter of claim 28, wherein the resonator electrodes each have a wide portion at its open end. 28. The dielectric filter of claim 27, wherein the resonator electrodes each have open ends at both ends thereof. 31. The dielectric filter of claim 30, wherein each of the resonator electrodes has at least one wide portion at its open end. 28. The method of claim 27, wherein at least one of the resonator electrodes, the end-to-end coupling capacitor electrode, and the input / output coupling capacitor electrode is formed by pattern printing of a conductive paste containing at least one of gold, silver, and copper. Dielectric filter. 28. The dielectric filter of claim 27, wherein at least one of the resonator electrodes, the end-to-end coupling capacitor electrode, and the input / output coupling capacitor electrode is formed of a metal foil containing at least one of gold, silver, and copper. . The method of claim 27, wherein the first and second dielectric substrate, respectively, A first dielectric part located at the center of each of the resonator electrodes; And And a second dielectric part having a lower dielectric constant than the first dielectric part and positioned on both sides of each of the resonator electrodes. The method of claim 34, wherein The end-to-end coupling capacitor electrode is positioned in the second dielectric portion of the second dielectric substrate, The third dielectric substrate includes the second dielectric portion, And the input / output coupling capacitor electrode is positioned in the second dielectric portion of the third dielectric substrate. The method of claim 34, wherein The first dielectric portion is formed of a ceramic material of one of Bi-Ca-Nb-O-based, Ba-Ti-O-based, and Zr (Mg, Zn, Nb) Ti-Mn-O-based, And the second dielectric portion is formed of a ceramic material of one of forsterite and alumina borosilicate glass. In the method for producing a dielectric filter, Stacking a first dielectric material and a second dielectric material having a lower dielectric constant than the first dielectric material to provide a composite dielectric block; Cutting the composite dielectric block parallel to the stacking direction of the first and second dielectric materials to provide composite dielectric substrates; Providing, respectively, end-to-end coupling capacitor electrodes, resonator electrodes, and input / output coupling capacitor electrodes on the composite dielectric substrates; And Stacking the composite dielectric substrates having the end-to-end coupling capacitor electrode, the resonator electrodes, and the input / output coupling capacitor electrode. 38. The method of claim 37, wherein providing the end-to-end coupling capacitor electrode, resonator electrodes, and input / output coupling capacitor electrode, Forming at least one of the end-to-end coupling capacitor electrode, the resonator electrodes, and the input / output coupling capacitor electrode through pattern printing of a conductive paste containing at least one of gold, silver, and copper. Method for producing a dielectric filter. 38. The method of claim 37, wherein providing the end-to-end coupling capacitor electrode, resonator electrodes, and input / output coupling capacitor electrode, Fabricating at least one of the inter-coupled capacitor electrode, the resonator electrodes, and the input / output coupled capacitor electrode with a metal foil containing at least one of gold, silver, and copper. Way. The method of claim 37, The first dielectric material is formed of a ceramic material of one of Bi-Ca-Nb-O-based, Ba-Ti-O-based and Zr (Mg, Zn, Nb) Ti-Mn-O-based, And the second dielectric material is formed of a ceramic material of one of forsterite and alumina borosilicate glass. In the method for producing a dielectric filter, Stacking a first dielectric material in the form of a green sheet and a second dielectric material in the form of a green sheet having a lower permittivity than the first dielectric material to provide a composite dielectric block in the form of a green sheet; Cutting the composite dielectric block in the form of a green sheet in parallel with the stacking direction of the first and second dielectric materials to provide composite dielectric substrates; Providing an end-to-end coupling capacitor electrode, a resonator electrode, and an input / output coupling capacitor electrode on the composite dielectric substrates in the green sheet form; Stacking the composite dielectric substrates in the form of the green sheet having the end-to-end coupling capacitor electrode, the resonator electrodes, and the input / output coupling capacitor electrode; And Firing the composite dielectric substrates in the form of the stacked green sheets. 42. The method of claim 41, wherein providing the end-to-end coupling capacitor electrode, resonator electrodes, and input / output coupling capacitor electrode, Providing at least one of the end-to-end coupling capacitor electrodes, the resonator electrodes, and the input / output coupling capacitor electrodes through pattern printing of a conductive paste containing at least one of gold, silver, and copper. Method for producing a filter. 42. The method of claim 41, wherein providing the end-to-end coupling capacitor electrode, resonator electrodes, and input / output coupling capacitor electrode, And providing at least one of the end-to-end coupling capacitor electrode, the resonator electrodes, and the input / output coupling capacitor electrode from a metal foil containing at least one of gold, silver, and copper. The method of claim 41, wherein The first dielectric material is formed of a ceramic material of one of Bi-Ca-Nb-O based, Ba-Ti-O based, and Zr (Mg, Zn, Nb) Ti-Mn-O based, And the second dielectric material is formed of a ceramic material of one of forsterite and alumina borosilicate glass. In the method for producing a dielectric filter, Stacking a first dielectric material in the form of a green sheet and a second dielectric material in the form of a green sheet having a lower permittivity than the first dielectric material to provide a ceramic dielectric block in the form of a green sheet; Cutting the composite dielectric block in the form of a green sheet in parallel with the stacking direction of the first and second dielectric materials to provide a plurality of composite dielectric substrates; Firing the plurality of composite dielectric substrates in the form of the green sheet; Providing an interstage coupling capacitor electrode, resonator electrodes, and input / output coupling capacitor electrode on the fired plurality of composite dielectric substrates; And Stacking the plurality of composite dielectric substrates having the end-to-end coupling capacitor electrodes, resonator electrodes, and input / output coupling capacitor electrodes. The method of claim 45, wherein the stacking of the plurality of composite dielectric electrodes comprises: Bonding the plurality of composite dielectric substrates to each other with a resin material containing a thermosetting resin. 47. The method of manufacturing a dielectric filter according to claim 46, wherein the resin material is a composite material containing a nonfat filler. 46. The method of claim 45, wherein laminating the plurality of composite dielectric substrates, And a plurality of composite dielectric substrates are joined by firing low melt glass frit. 46. The method of claim 45, wherein providing the end-to-end coupling capacitor electrode, resonator electrodes, and input / output coupling capacitor electrode, At least one of the inter-coupled capacitor electrode, the resonator electrodes, and the input-output coupled capacitor electrode is provided by pattern printing of a conductive paste containing at least one of gold, silver, and copper. . 46. The method of claim 45, wherein providing the end-to-end coupling capacitor electrode, resonator electrodes, and input / output coupling capacitor electrode, And providing at least one of the end-to-end coupling capacitor electrode, the resonator electrodes, and the input / output coupling capacitor electrode from a metal foil containing at least one of gold, silver, and copper. The method of claim 45, The first dielectric material is formed of a ceramic material of one of Bi-Ca-Nb-O-based, Ba-Ti-O-based, and Zr (Mg, Zn, Nb) Ti-Mn-O-based, And the second dielectric material is formed of a ceramic material of one of forsterite and alumina borosilicate glass. In antenna commons, An antenna port; 37. A filter comprising: a first filter comprising a dielectric filter according to any one of claims 27 to 36, coupled to said antenna port; And And a second filter coupled to the antenna port. In antenna commons, An antenna port; 37. A filter comprising: a first filter comprising a dielectric filter according to any one of claims 27 to 36, coupled to said antenna port; And An antenna common device comprising a dielectric filter according to any one of claims 27 to 36 and having a second filter coupled to said antenna port. A communication device comprising the antenna common according to claim 52 or 53. 37. A communications device comprising the dielectric filter of any of claims 27-36.