JP3010568U - Dielectric filter and its coupling structure - Google Patents

Abstract

(57) [Abstract] [Purpose] To make it possible to inexpensively construct a high-performance, ultra-small duplexer, etc. [Configuration] On the lower surface of the dielectric block 2 of the first dielectric filter 1a, a resonator hole on one end side A groove 8 is formed in the vicinity of the groove 3 in parallel with the groove 3, and an island-shaped electrode film 8a independent of the outer conductor film 6 is formed on the inner surface of the groove 8. On the upper surface of the dielectric block 2 of the second dielectric filter 1b, a ridge 9 is formed in parallel with the resonator hole 3 on the one end side, and the outer conductor film is formed on the upper surface of the ridge 9. The island-shaped electrode film 9a is formed independently of the film 6. The concave groove 8 of the first dielectric filter 1a and the convex stripe 9 of the second dielectric filter 1b are fitted to each other to form the island-shaped electrode film 8a of the concave groove 8 and the island-shaped electrode film 9a of the convex stripe 9. Connect facing each other.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a dielectric filter used in a high frequency circuit of a mobile communication device such as a mobile phone, and in particular, combining and combining a plurality of dielectric filters such as a duplexer and a duplexer. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter suitable for a high frequency component to be constructed and its coupling structure.

[0002]

[Prior art]

 In mobile communication devices such as car phones, cordless phones, and specified low-power transceivers, a duplexer is placed at the feeding point of one antenna to share the transmitting and receiving antennas. The duplexer is a circuit that separates the transmission frequency from the reception frequency, and removes unnecessary frequencies such as external noise.It prevents mismatch when the reception system becomes a load when the antenna is viewed from the transmission system, and it also separates the reception system from the antenna. Even if you look at it, it is important to prevent mismatches due to the load on the transmission system.

In recent mobile communication devices, many duplexers use a so-called combline structure integrated dielectric filter. As is well known, in this dielectric filter, multiple resonator holes are formed in parallel in a substantially rectangular parallelepiped dielectric block, and if necessary, coupling holes are formed between the resonator holes. Are formed, and an outer conductor film is formed on the other five surfaces of the dielectric block except one surface of the dielectric block in which one end of the resonator hole and the coupling hole is open. An inner conductor film, one end of which is continuous with the outer conductor film, is formed on the peripheral surface.

Then, in order to connect to an external circuit, predetermined input / output terminal pins are mounted so as to be capacitively coupled to the resonator holes generally located on both sides. The input / output terminal pin may be inserted and arranged in the resonator hole through a resin cylindrical holder, or a separate input / output terminal hole may be formed further outside the resonator hole in parallel with the resonator hole. In some cases, the I / O terminal pin is formed and inserted and arranged in the hole (the inside of which is metallized).

A plurality (usually two) of dielectric filters having such a configuration are used, and one of the input / output terminals is connected to serve as an antenna side terminal, and the other input / output terminal of each dielectric filter is transmitted. It will be connected to the side circuit / reception side circuit.

By the way, the relationship between the resonance frequencies f1 and f2 (f1> f2) of the two dielectric filters is shown in an impedance chart as shown in FIGS. 8 (A) and 8 (B). As shown in FIG. 3A, when viewed from the side of one dielectric filter (resonance frequency f1), the phase of frequency f2 of the other dielectric filter is C-shaped, and as shown in FIG. When viewed from the other dielectric filter (resonance frequency f2) side, the phase of the frequency f1 of the one dielectric filter is L-shaped.

Although the other party's frequency is in the vicinity of infinity, in order to construct a duplexer by combining both such filters, the reflection impedance in the other party's band seen from the antenna side is made to be near infinity. , It is necessary to eliminate the influence on the other side.

Therefore, conventionally, an LC type phase shifter of a π type or a T type of a coil and a condenser by a lumped constant is inserted between both filters, or a coaxial cable or a printed board having a predetermined length is inserted. By connecting the specified input and output terminals of both filters with the transmission line formed above, the phase is rotated and the frequency of the other party is made infinite.

[0009]

[Problems to be solved by the device]

 Since the former LC type phase shifter inserted between both filters (transmission / reception filter) is a π-type or T-type lumped constant circuit consisting of a coil and a capacitor, the duplexer adopting this configuration has a small number of parts. However, the mounting layout becomes difficult and the mounting process becomes troublesome, which is an obstacle to miniaturization and cost reduction. Further, at a high frequency of 900 MHz or more, the LC type phase shifter does not operate as a lumped constant circuit, and there is a problem that its design and adjustment are extremely difficult.

When connecting the latter coaxial cable or transmission line, an external component such as a coaxial cable is required as in the above case, which is not only expensive in that respect but also the coaxial cable or the like. When connected, the phase rotates to the TG side, and the longer the length of the coaxial cable, etc., the greater the rotation. Therefore, when the frequency of the other party is C-shaped ((A) in the figure), the angle to rotate also becomes large, so the length of the coaxial cable to be used also becomes long and the installation area (occupied area) becomes large. Have a problem.

The present invention has been made in view of the above background, and an object of the present invention is to solve the above problems and to configure a high-performance, ultra-compact duplexer, triplexer, and other high-frequency components at low cost. (EN) Provided are a dielectric filter and a coupling structure thereof, which can realize a simple structure and can easily perform phase matching without using a special external component when coupling a plurality of dielectric filters. Especially.

[0012]

[Means for Solving the Problems]

 In order to achieve the above object, in the dielectric filter according to the present invention, an outer conductor film is formed on a predetermined portion of the outer surface of a substantially rectangular parallelepiped dielectric block having a plurality of resonator holes, and the resonator holes are formed. A dielectric filter in which an inner conductor film, one end of which is continuous with the outer conductor film, is formed on the inner peripheral surface of the dielectric block, and the dielectric filter is provided on the outer surface of the dielectric block in the vicinity of the resonator hole on the one end side. Concave grooves are formed in parallel, and the island-shaped electrode film independent of the outer conductor film is formed on the inner surface of the groove.

Further, as another means for solving the problem, in place of the concave groove, on the outer surface of the dielectric block, a convex stripe is formed in parallel with the resonator hole on the one end side in the vicinity of the resonator hole, and the convex stripe is formed. The island-shaped electrode film independent of the outer conductor film is formed on the upper surface of the.

Further, as another means for solving the problems, on the outer surface of the dielectric block, a concave groove or a convex line is formed in parallel with the resonator hole on one end side and the other end side, and the concave groove is formed. The inner electrode of the groove or the upper surface of the ridge is formed so that an island-shaped electrode film independent of the outer conductor film is formed.

Further, in the dielectric filter coupling structure according to the present invention, a plurality of predetermined dielectric filters having the above-mentioned configuration are used, and when coupling them, the concave groove formed in one dielectric filter and the other dielectric filter are formed. The two dielectric filters are coupled by fitting the ridges formed on the body filter and connecting the island-shaped electrode film of the concave groove and the island-shaped electrode film of the ridge to face each other. Therefore, a duplexer is constructed by combining two dielectric filters.

[0016]

[Action]

 Among the plurality of dielectric filters adjacent to each other, the concave groove of one of the dielectric filters and the convex stripe of the other dielectric filter are fitted to each other, and the island-shaped electrode film of the concave groove and the convex groove are formed. By connecting the strip-shaped island-shaped electrode films so as to face each other, both dielectric filters are coupled. Which dielectric filter is provided with the concave groove and which is provided with the convex stripe is determined according to the phase characteristics of both. Specifically, it is preferable to form a concave groove when the counter frequency is C-shaped and to form a ridge when the counter frequency is L-shaped. Then, the phase can be rotated in a desired direction without making the depth of the concave groove or the height of the convex stripe too large, and the phase can be made almost infinite. Further, the coupling capacitance between the resonator hole of each dielectric filter and the island-shaped electrode film can be freely set by the width of the groove and the ridge and the formation position and size of the island-shaped electrode film. Therefore, it is possible to easily make the depth of the concave groove to be matched and the height of the convex line substantially coincident with each other.

[0017]

【Example】

 Hereinafter, preferred embodiments of a dielectric filter and its coupling structure according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a schematic structure of a dielectric filter 1a with a concave groove which is a first embodiment of the dielectric filter according to the present invention. In this structure, five resonator holes 3 and four coupling holes 4 are alternately formed in parallel in a substantially rectangular dielectric block 2, and one end of each of the resonator holes 3 and the coupling holes 4 is formed. The outer conductor film 6 is formed on the other five surfaces except the front surface 2a of the dielectric block 2 which is open, and one end of the inner peripheral surface of the resonator hole 3 is continuous with the outer conductor film 6. It is a dielectric filter in which an internal conductor film 7 is formed. In the present invention, a groove 8 is formed in the lower surface of the dielectric block 2 in the vicinity of the resonator hole 3 on one end side in parallel with the hole 3, and the inner surface of the groove 8 is covered with the outer conductor film 6 An independent island-shaped electrode film (input / output electrode) 8a is formed.

With such a configuration, it is possible to capacitively couple between the resonator hole 3 on one end side and the island-shaped electrode film 8a, and to transmit / receive a signal to / from an external circuit. Although not specifically shown, the resonator hole on the other end side (right end in the figure) is inserted with an input / output terminal pin through a cylindrical holder made of synthetic resin, for example, and connected to an external circuit. It becomes possible to send and receive the signal.

By forming the concave groove 8 as described above, the distance between the resonator hole 3 and the island-shaped electrode film 8a is shortened, so that the coupling force is strengthened. Then, as compared with a dielectric filter having a normal shape in which the groove 8 is not provided, the phase with the frequency of the other side rotates in the TL direction, and the angle of rotation is determined by the depth of the groove 8a ( The deeper it rotates, the greater it will be). Therefore, as shown in FIG. 8A, when the phase of the opposite frequency is C-shaped, the groove 8 is formed as in this embodiment to rotate the phase by a predetermined angle to make it infinite. be able to.

FIG. 2 shows a schematic configuration of a dielectric filter 1b with a ridge, which is a second embodiment of the dielectric filter according to the present invention. The basic structure of this is the same as that of the dielectric filter 1a, and the same or corresponding parts are designated by the same reference numerals. The characteristic point of this dielectric filter 1b is that a convex strip 9 is formed in parallel with the resonator hole 3 on one end side on the upper surface of the dielectric block 2, and the upper surface of the convex strip 9 has an external shape. The point is that the island-shaped electrode film 9a independent of the conductor film 6 is formed.

With such a configuration, it is possible to capacitively couple between the resonator hole 3 on one end side and the island-shaped electrode 9a, and to transmit / receive a signal to / from an external circuit. Since it is formed on the upper surface of the protrusion 9, the distance between the resonator hole 3 and the island-shaped electrode film 9a is longer than that in the normal case, which is contrary to the first embodiment, and the coupling force is weakened. . And this is similar to the case where a coaxial cable is attached, and the phase with the frequency of the other side rotates in the TG direction compared to a dielectric filter of a normal shape without the ridge 9 and the angle of rotation. Is determined by the height of the ridge 9 (the higher the height, the greater the rotation). Therefore, as shown in FIG. 8B, when the phase of the opposite frequency is L-shaped, the ridge 9 is formed as in the present embodiment to rotate the phase by a predetermined angle to make it infinite. be able to.

A duplexer can be constructed by using the dielectric filters 1a and 1b of the above-described embodiments by combining and coupling them as shown in FIG. First, the resonance frequency f1 of the first dielectric filter 1a and the resonance frequency f2 of the second dielectric filter 1b are in the relationship of f1> f2, and in the state where the groove 8 and the ridge 9 are not provided, As a reference, it is assumed that the partner frequency f2 has a C-like relationship (the relationship shown in FIG. 8A).

In accordance with such a premise, the concave groove 8 of the first dielectric filter 1 a and the convex groove 9 of the second dielectric filter 1 b are fitted to each other, and the island-shaped electrode film 8 a of the concave groove 8 and the convex groove 9 are projected. The island-shaped electrode film 9a of the strip 9 is opposed and connected. Of course, the formation positions and dimensions of the concave grooves 8, the convex stripes 9 and the island-shaped electrode films 8a and 9a are set so as to be in a combined state as shown in FIG.

Then, the first dielectric filter 1a and the second dielectric filter 1b are electrically connected by the island-shaped electrode films 8a and 9a. Therefore, both filters 1a and 1b can transmit and receive a signal to and from an external circuit from the joint surface, and serve as terminals for antenna joining in the duplexer.

Further, as described above, in the first dielectric filter 1a, by providing the concave groove 8, it is possible to rotate the partner frequency to the TL side by a predetermined angle, and the second dielectric filter 1b. Since the ridge 9 is provided, the other party's frequency can be rotated to the TG side by a predetermined angle, so that the phase of the other party's frequency can be adjusted to an infinite position. If the absolute values of the C- and L-property phase angles are the same when the groove 8 and the ridge 9 are not formed, it is necessary to rotate the phase of the opposite frequency to make the groove infinite. Since the depth of 8 and the height of the ridge 9 are equal, the two dielectric filters 1a and 1b can be joined as they are without any other parts. When the angles are different, it is possible to match the depth and height by appropriately changing the areas of the island-shaped electrode films 8a and 9a. Can be dealt with by interposing an appropriate spacer. Even if such spacers are provided, the spacers are present between both filters and do not project to the outside, so there is no risk of upsizing, and they are used only for position (gap) adjustment. Therefore, since it does not affect the circuit at all, it does not cause the troublesome adjustment and the high cost unlike the conventional external parts.

FIG. 4 shows the construction of another embodiment of the coupling structure (duplexer) according to the present invention. In the above-mentioned embodiment, the convex strip 9 is formed on the upper surface of the one dielectric block 2 and the concave groove 8 is formed on the lower surface of the other block. On the other hand, in the embodiment of FIG. 4, the groove 8 is formed on the right side surface of the dielectric block 2 of the first dielectric filter 1a ', and the left side surface of the dielectric block 2 of the second dielectric filter 1b' is formed. The ridge 9 is formed on the bottom. The side surfaces of both dielectric blocks 2 are joined together. Since the other configurations and operational effects are similar to those of the above-described embodiment, the same reference numerals are given and detailed description thereof will be omitted.

FIG. 5 shows the configuration of still another embodiment of the present invention. In the third dielectric filter 1c shown in the figure, a groove 8 is formed in parallel with the resonator hole 3 on one end side on the upper surface of the dielectric block 2 and the inner surface of the groove 8 is formed. Is formed with an island-shaped electrode film 8a independent of the external conductor film 6, and a ridge 9 is formed in the lower surface of the dielectric block 2 in the vicinity of the resonator hole 3 on the other end side in parallel therewith. The island-shaped electrode film 9a independent of the outer conductor film 6 is formed on the top surface of the ridge 9.

Then, as indicated by the chain double-dashed line, the second dielectric filter 1b having a ridge is coupled to the upper surface side of the third dielectric filter 1c, and the lower surface side of the third dielectric filter 1c is It is possible to combine the first dielectric filter 1a with the groove. As a result, a triplexer can be configured, and if the first dielectric filter 1a is used as a local filter and the third dielectric filter 1c is used as a reception filter, local and reception can be combined, and the mixer is stable. And it can be simplified. Further, by providing a plurality of third dielectric filters 1c, it is possible to further increase the number of stages (combiner of filters having a plurality of resonance frequencies).

Further, the coupling structure for joining three or more dielectric filters in this way is not limited to the one described above, and for example, as shown in FIG. 6, a second dielectric filter 1b and The third dielectric filter 1c 'and the third dielectric filter 1c' are joined in a state where they are arranged vertically, and the first dielectric filter 1a and the third dielectric filter 1c 'are laterally arranged in a lateral state. Although not shown, the structure may be reversed from that shown in FIG. 6, all the dielectric filters may be connected side by side, or any other combined state may be adopted. .

FIG. 7 shows another embodiment of the formation position of the island-shaped electrode film 8a in the concave groove 8 (same as the island-shaped electrode film 9a in the ridge 9). As shown, the island-shaped electrode film 8a can be formed close to the front surface 2a of the block 2.

In the above-described embodiment, the example applied to the duplexer or triplexer has been described, but the present invention is not limited to the above-mentioned embodiment, and various dielectric filters formed by joining a plurality of dielectric filters are formed. It can be applied to high frequency components.

The coupling holes shown in each of the above embodiments do not necessarily have to be provided, and the invention can be applied to an interdigital type.

[0033]

[Effect of device]

 As described above, in the dielectric filter and its coupling structure according to the present invention, it is possible to appropriately capacitively couple a plurality of dielectric filters without using any other element, and the coupling characteristics can be made uniform with high accuracy. Can be kept at This capacitive coupling can be made to function as a phase shifter between the transmission and reception filters, and therefore high-performance, ultra-compact high-frequency components such as duplexers and triplexers can be realized at low cost. In particular, since it operates as a stable phase shifter even in the band of 900 MHz or more, it is a very effective technique for realizing an ultra-compact and high-performance mobile communication device such as a mobile phone.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a dielectric filter according to the present invention.

FIG. 2 is a perspective view showing a second embodiment of the dielectric filter according to the present invention.

FIG. 3 is a diagram showing a combined state of first and second dielectric filters.

FIG. 4 is a view showing another embodiment of the present invention in which the forming positions of the groove and the ridge are different.

FIG. 5 is a view showing another embodiment of the present invention having both a convex stripe and a concave groove.

FIG. 6 is a view showing still another embodiment of the present invention having both a ridge and a groove.

FIG. 7 is a view showing another embodiment of the present invention in which the formation position of the island-shaped electrode film is different.

FIG. 8 is a diagram for explaining a conventional problem.

[Explanation of symbols]

 1a, 1a '1st dielectric filter 1b, 1b' 2nd dielectric filter 1c, 1c '3rd dielectric filter 2 Dielectric block 3 Resonator hole 4 Coupling hole 6 External conductor film 7 Inner conductor film 8 Recessed groove 8a Island-shaped electrode film 9 Projected line 9a Island-shaped electrode film

Claims (5)

[Scope of utility model registration request] 1. An outer conductor film is formed on a predetermined part of an outer surface of a substantially rectangular parallelepiped dielectric block having a plurality of resonator holes, and one end of the outer conductor film is formed on the inner peripheral surface of the resonator hole. A dielectric filter having a continuous internal conductor film formed, wherein a groove is formed in the outer surface of the dielectric block in the vicinity of the resonator hole on one end side in parallel therewith, and an inner surface of the groove is formed. The dielectric filter is characterized in that an island-shaped electrode film independent of the external conductor film is formed on the film. 2. An outer conductor film is formed on a predetermined portion of an outer surface of a substantially rectangular parallelepiped dielectric block having a plurality of resonator holes, and one end of the outer conductor film is formed on the inner peripheral surface of the resonator hole. A dielectric filter having a continuous internal conductor film formed, wherein a protrusion is formed in the outer surface of the dielectric block in the vicinity of the resonator hole on one end side in parallel therewith, and an upper surface of the protrusion is formed. The dielectric filter is characterized in that an island-shaped electrode film independent of the external conductor film is formed on the film. 3. An outer conductor film is formed on a predetermined portion of the outer surface of a substantially rectangular parallelepiped dielectric block having a plurality of resonator holes, and one end of the outer conductor film is formed on the inner peripheral surface of the resonator hole. A dielectric filter in which a continuous inner conductor film is formed, wherein a groove or a ridge is formed in parallel with the resonator hole on one end side and the other end side in the vicinity of the resonator hole on the outer surface of the dielectric block. The dielectric filter is characterized in that an island-shaped electrode film independent of the outer conductor film is formed on the inner surface of the concave groove or the upper surface of the ridge. 4. The dielectric filter according to claim 1 and the dielectric filter according to claim 2, wherein the concave groove provided in the dielectric filter according to claim 1 is provided. The above-mentioned projection provided on the dielectric filter described in (3) is fitted, and the island-shaped electrode film of the groove and the island-shaped electrode film of the projection are connected to face each other. Dielectric filter coupling structure. 5. A predetermined number of the dielectric filter according to claim 1 and the dielectric filter according to claim 2.
In the coupling structure of the dielectric filters, which is configured to be connected via the dielectric filter according to, the joint surface between adjacent dielectric filters has a concave groove provided in one of the dielectric filters and the other. And the projections provided on the dielectric filter are arranged so as to be opposed to each other, and both are fitted to each other, and the island-shaped electrode film of the concave groove and the island-shaped electrode film of the projection are connected to face each other. Characteristic dielectric filter coupling structure.