Wave transmission lines and networks – Coupling networks – Wave filters including long line elements
Reexamination Certificate
1998-12-29
2001-01-30
Pascal, Robert (Department: 2817)
Wave transmission lines and networks
Coupling networks
Wave filters including long line elements
C333S204000, C333S134000
Reexamination Certificate
active
06181223
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a dielectric duplexer device comprising a plurality of resonators and adapted to be suitably be used for a mobile telephone set such as an automobile telephone set or a portable telephone set.
PRIOR ART
Japanese Patent Kokai No. 63-311801 discloses a dielectric duplexer device comprising a dielectric duplexer including a plurality of resonators arranged in parallel in a direction on a dielectric ceramic block which has outer peripheral surface coated with an grounding conductor except an open-circuit end surface where through holes of the resonators are exposed. The dielectric duplexer is mounted on a substrate provided with a coupling circuit which is coupled to the related resonators of the dielectric duplexer. The dielectric ceramic block of said dielectric duplexer and said coupling circuit are housed in and covered by a metal casing. Various similar dielectric duplexer devices have also been proposed to date.
In such a dielectric duplexer device, circuit elements such as coupling capacitors for LC-coupling the resonators are mounted on the substrate and electric paths are formed on the substrate to produce required circuits. The circuit elements and electric paths are then covered by a metal casing operating as shield case. Input/output electrodes are formed on the substrate for connection with external electric paths to realize the dielectric duplexer device in the form of an integral unit that provides easy handling. Additionally, such an arrangement provides an enhanced degree of design freedom because coupling capacitors and other elements may be mounted independently on the substrate so that appropriate values may be selected for the circuit constants.
However, with such a conventional arrangement, each of the resonators is provided with a metal terminal driven into it in order to realize an LC-coupling for the resonators and the metal terminals are connected to related electric paths formed on the printed substrate or board, while coupling capacitors have to be mounted on the substrate, so that, as a whole, the dielectric duplexer requires a cumbersome operation of connecting wires and involves a considerable number of assembling steps reflecting a complicated circuit design and a clumsy circuit arrangement.
In an attempt to avoid the above problem, the inventor of the present patent application proposed a dielectric duplexer assembly comprising a laminated circuit arrangement for coupling circuit realized by laminating a plurality of dielectric sheet materials and arranged on the open-circuit end surface of the dielectric duplexer, the coupling circuits being connected to the related resonators of the transmitter section and/or the receiver section of the duplexer.
FIG. 1
of the accompanying drawings shows such a dielectric duplexer device A, in which connector pads P are exposedly arranged on a layered side portion of a laminated circuit arrangement B where the layered side portion of the laminated circuit arrangement appears, and a flat side portion perpendicular to said layered side portion of the laminated circuit arrangement B is bonded to the open-circuit end surface of a dielectric duplexer C comprising a plurality of resonators D. However, as a result of a series of experiments, it has been found that the previously proposed device is accompanied by the following problems.
a) The laminated circuit arrangement B is arranged so that one of the layered side portions of dielectric sheet members (opposite side portions along which the dielectric sheet members are laminated) is disposed on the surface of the printed circuit board and thus forms a boundary surface that is less smooth. There are arisen problems that floatings and gaps may be produced between the surface of the printed circuit board and the layered side portion which is brought into contact with that surface. In short, this conventional arrangement does not provide a satisfactory flatness, and the dielectric duplexer and the laminated circuit arrangment cannot be mounted stably on the printed circuit board.
b) A large surface area of the flat side portion perpendicular to the layered side portion of the laminated circuit arrangment B results in a large height of the device to baffle the effort for downsizing the portable telephone set incorporating the device.
Thus, the surface area is subjected to limitations to consequently limit the surface area of the capacitor electrodes arranged on the surface of the dielectric laminated circuit arrangement and hence the allowable capacitance range for the capacitors.
It is, therefore, an object of the present invention is to provide a dielectric duplexer device that is capable of overcoming these problems.
SUMMARY OF THE INVENTION
According to the invention, there is provided a dielectric duplexer device comprising a dielectric duplexer having a plurality of resonators arranged in parallel in a direction and divided into two sections, a transmitter section and a receiver section, and a coupling circuit connected to predetermined ones of the resonators of the transmitter section and/or receiver section of the dielectric duplexer, wherein said coupling circuit comprises a laminated circuit arrangement including a plurality of dielectric sheet members and bonded to an open-circuit end surface of the dielectric duplexer at a lateral layered side portion thereof so that an intended transmission/reception circuit is formed.
Such an arrangement, where the dielectric laminated circuit arrangement is bonded to the open-circuit end surface of the dielectric duplexer to provide a coupling circuit, makes the assembly show a neat and simple profile and allows appropriate values to be selected for the circuit constants.
Additionally, since the dielectric laminated circuit arrangement is bonded to the open-circuit end surface of the dielectric duplexer at a rear layered side portion, a highly smooth entire surface of the outermost or lowest dielectric sheet member is made to face and stably mounted on a printed circuit substrate.
Then, the height, or thickness, of the dielectric laminated circuit arrangement is invariable to make it compatible with the effort of downsizing the portable telephone set comprising it, if the surface area of the dielectric sheet members to be laminated is changed appropriately.
Preferably, the dielectric duplexer may comprise a plurality of coaxial type resonators arranged in parallel, each being made of a dielectric block which has a single through hole extending therethrough and having its inner surface coated with an inner conductor, an outer surface coated with a grounding conductor and an open-circuit end surface having no conductor.
With such an arrangement, the characteristics of each of the coaxial type resonators can be regulated independently to optimize the operating characteristics of the dielectric duplexer as a whole. The coaxial type resonators may be unitized in advance or assembled together by rigidly mounting them on the substrate on a one by one basis.
Alternatively, the dielectric duplexer may comprise a plurality of coaxial type resonators provided on a single dielectric block which has a plurality of through holes extending in parallel along a same direction therethrough, an outer surface coated with a grounding conductor and an open-circuit end surface having no conductor, each through hole having an inner surface coated with an inner conductor.
With such an arrangement, the dielectric duplexer can be mounted on the substrate with ease because it is made of a single dielectric block.
According to a preferable embodiment, the laminated circuit arrangement may constitute a coupling circuit having a low pass filter circuit section coupled to the resonators of one of the resonator sections and a band pass filter circuit section coupled to the resonators of the other resonator section.
According to another preferable embodiment, the laminated circuit arrangement may constitute a coupling circuit having a low pass filter section coupled to the resonators of one of th
Larson & Taylor PLC
NGK Spark Plug Co. Ltd.
Nguyen Patricia T.
Pascal Robert
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