JPH0352005Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a dielectric duplexer that combines a plurality of λ/4 resonance type multistage dielectric filters. The present invention relates to a dielectric duplexer in which each dielectric filter is held by a plate and is mounted and bonded to a metal base having holes provided in positions corresponding to the resonator holes.

[Prior Art] In the field of mobile communications such as car phones and mobile phones, duplexers using multistage dielectric filters made of barium titanate or the like are used.

A multistage dielectric filter consists of a rectangular parallelepiped dielectric block, which has a plurality of resonator holes spaced apart from each other in the longitudinal direction, and a conductive layer such as metallization on the inner surface of the resonator holes, the top or bottom surface, and all sides of the block. This structure has a large number of resonant elements having a resonant wavelength four times the length of the resonator hole.

As shown in Figure 4, the conventional dielectric duplexer has the following characteristics:
The configuration is such that a plurality of dielectric filters 10 as described above (two in this example) are combined and housed in a metal casing 12. As the metal housing 12, a die-cast product of aluminum or the like is generally used. The metal housing 12 has a plurality of grooves 13 and has input/output terminals 14 attached to both ends.
A dielectric filter 10 is accommodated in each of the grooves 13,
A structure is adopted in which a predetermined electrical connection is made between both filters 10 or between the input and output terminals 14 using lead wires 15, and a metal lid 16 is covered.

In such a dielectric duplexer, the metal housing 12
If the electrical connection between the dielectric filter 10 and the outer conductor layer of the dielectric filter 10 is poor, sufficient grounding cannot be achieved and the characteristics deteriorate. Therefore, usually a metal casing 1
A metal plate 18 having spring properties is interposed between the inner wall of the filter 2 and the dielectric filter 10.

[Problems to be solved by the invention] However, in the configuration in which the dielectric filter 10 is accommodated in each groove 13 formed in the metal casing 12, if the dimensional accuracy between the groove 13 and the filter 10 is not sufficiently high, the position of the filter may be changed. is not determined, and a large spurious (2
There is a disadvantage that spurious waves (harmonics) appear and the spurious waves change depending on the distance between the lid 16 and the filter 10.

Furthermore, in order to adjust the resonance frequency of each resonance element during assembly, the lid 16 must be attached and removed many times. In other words, the housing 12
Measurement is performed with the lid 16 attached to the resonator, and if there is any inconvenience, the lid 16 is removed, the metallized layer of the resonator hole is ground, and the lid 16 is reattached and measured to achieve the desired characteristics. . For this reason, the number of adjustment steps is extremely large, which also has the disadvantage of poor workability.

The purpose of this invention is to eliminate the above-mentioned drawbacks of the conventional technology, to provide excellent earthquake resistance and to suppress the occurrence of spurious signals, to significantly reduce the number of adjustment steps, and to achieve miniaturization and cost reduction. The purpose of this invention is to provide a dielectric duplexer that can

[Means for Solving the Problems] The present invention, which can achieve the above objects, uses a dielectric demultiplexer having a structure in which a plurality of block-shaped λ/4 resonant multi-stage dielectric filters are combined. In the device, each dielectric filter is held in close contact with metal separators that are in close contact with each other so as to isolate the filters, and a metal frame plate that is bent in a U-shape and surrounds the outer surface of the filter, and these metal separators and metal This is a dielectric duplexer with a structure in which a frame plate is mounted and bonded to a metal base. Here the metal base is
An adjustment filter is provided facing the open surface of each dielectric filter (the surface on which the resonator hole is opened and which does not have a conductive layer formed thereon), and is located at a position corresponding to each of these resonant elements. It has a structure in which holes are formed and input/output terminals are attached.

[Function] The outer surface of each dielectric filter is completely surrounded by the metal separator and the metal frame plate and held in close contact with each other. The metal separator and the metal frame plate are connected and fixed to the metal base at their edges. Therefore, good electrical continuity is achieved between the outer conductor layer of each dielectric filter and the metal base, and the distance between the open surface of the dielectric filter and the metal base is kept constant by the metal separator and the metal frame plate. is maintained. Therefore, there is less spurious noise, and
Characteristics can be stabilized without spurious changes.

In addition, in the present invention, since holes are formed at positions corresponding to the resonator holes in the metal base, the frequencies of each resonant element can be adjusted using the holes.
Since there is no need to remove or install the lid, the number of adjustment steps can be significantly reduced.

[Embodiment] FIG. 1 is an exploded perspective view showing an embodiment of a dielectric duplexer according to the present invention, and FIG. 2 is a perspective view of the same after assembly. This dielectric duplexer 20 mainly includes two λ/4 resonance type five-stage dielectric filters 22 having a block shape, a metal separator 24 that isolates both filters 22, and a metal separator 24 that surrounds the outer surface of the filter 22. It is composed of a metal frame plate 26 and a metal base 28.

The structure of the dielectric filter 22 may be basically the same as that of a conventional filter. Five resonator holes 30 are provided at predetermined intervals in the longitudinal direction of a rectangular parallelepiped dielectric block made of dielectric ceramic such as barium titanate, and a coupler hole 32 is provided between them. One of the open surfaces (the lower surface in this embodiment) is an open surface 34, and a conductive layer is formed by metallization or the like on all other side surfaces, the upper surface, and the inner surface of the resonator hole 30.

The metal separator 24 is simply a flat plate, whereas the metal frame plate 26 is a sheet metal workpiece bent into a U-shape. The length of the metal separator 24 and the metal frame plate 26 is slightly longer than that of the dielectric filter 22, and the height thereof is also slightly higher. The metal separator 24 is located between both dielectric filters 22, and the metal frame plate 26 is tightly fixed by soldering or conductive adhesive, etc., so as to cover the outer surface of the dielectric filter 22. At this time, the upper surface of the dielectric filter 22 and the metal separator 24 and metal frame plate 26
The upper edges of the two are aligned so that the distance from their lower edges to the open surface 34 is always constant.

The metal base 28 is located so as to face the open surface 34 of the dielectric filter 26, and has holes 36 at positions corresponding to the respective resonator holes 30 of the dielectric filter 22, and has holes 36 near both ends. This is a configuration in which an input/output terminal 38 is attached. On the surface facing the open surface 34, an appropriate number of protrusions 40 for positioning are provided at appropriate positions so that the metal separator 24 and the metal frame plate 26 can be easily mounted. Further, mounting notches 42 are formed at both ends for fixing devices and the like.

As described above, the dielectric filter 22 is clamped by the metal separator 24 and the metal frame plate 26 on its outer surface, and the metal separator 24 and the metal frame plate 26
The lower end of 6 is mounted on a metal base 28 and connected and fixed by soldering, welding, or the like.

A predetermined electrical connection is made to the input/output terminals 38 and lead wires using coupling capacitors 44 and the like provided on the open ends of the resonator holes at both ends of the dielectric filter 22 . The frequency of the resonator hole 30 of the dielectric filter 22 is adjusted using the hole 36 formed in the metal base 28. After the adjustment is completed, the surface of the metal base 36 and the surface opposite to the metal base are covered with a thin metal plate or the like to prevent leakage of radio waves.

With such a structure, the characteristics become extremely stable and the generation of spurious signals can be suppressed. The situation is shown in Figure 3. In the figure, the solid line is the characteristic diagram of the product of the present invention, and the broken line is the characteristic diagram of the conventional product. The reason why this invention can significantly suppress spurious noise is that the dielectric filter is closely held by a metal separator or metal frame plate, and they are attached to a metal base for good electrical connection. This is because there is no intervening metal plate or the like, so that the dielectric filter is firmly held so as not to be displaced, and the distance between the open surface of the dielectric filter and the metal base can be maintained at an optimal constant state.

Although the above embodiments all use five-stage filters, it goes without saying that the present invention is not limited to the configuration of the above embodiments. A multi-stage filter can be used instead of only five stages, and the two filters may have the same or different number of stages depending on the required characteristics.

[Effects of the invention] As described above, the present invention surrounds a dielectric filter with a metal separator and a metal frame plate and holds it in close contact, and also mounts and connects it to a metal base with holes formed at positions corresponding to the resonator holes. Because of this structure, the dielectric filter is directly fixed to the metal separator or metal frame plate, so it does not displace and has excellent earthquake resistance, and the electrical connection between the outside surface of the filter and the metal base is good, and the open surface of the filter and the metal Since the distance from the base can be maintained at an optimal constant state, it has an excellent effect of suppressing spurious waves and stabilizing the characteristics.

Additionally, the present invention eliminates the need to remove and attach the lid each time an adjustment is made, allowing direct adjustment using the holes in the metal base, which has the effect of greatly simplifying the number of adjustment steps.

Furthermore, since the present invention only requires sheet metal processing, the manufacturing cost can be significantly reduced compared to conventional die-cast products, and it also has the advantage of being smaller and lighter.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing an embodiment of the dielectric duplexer according to the present invention, Fig. 2 is a perspective view showing its assembled state, and Fig. 3 is attenuation characteristics of the inventive product and the conventional product. FIG. 4 is a diagram showing an example of the conventional technology. 20... Dielectric duplexer, 22... Dielectric filter, 24... Metal separator, 26... Metal frame plate, 28... Metal base, 30... Resonator hole 3
4...open surface, 36...hole, 38...input/output terminal.

Claims (1)

[Claims for Utility Model Registration] In a duplexer having a structure in which a plurality of λ/4 resonant multi-stage dielectric filters in a block shape are combined, a metal separator and a metal separator that are in close contact with each other so as to isolate the dielectric filters from each other are used. , each dielectric filter is held in close contact with a metal frame plate bent into a U-shape that surrounds the outer surface of the dielectric filter, and placed at a position corresponding to each resonator hole facing the open surface of each dielectric filter. A dielectric duplexer in which the metal separator and metal frame plate are mounted and bonded to a metal base having holes and input/output terminals.