Wave transmission lines and networks – Plural channel systems – Having branched circuits
Reexamination Certificate
2000-02-14
2001-02-06
Pascal, Robert (Department: 2817)
Wave transmission lines and networks
Plural channel systems
Having branched circuits
C333S206000, C333S222000
Reexamination Certificate
active
06184759
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a dielectric filter comprising a plurality of dielectric blocks and a transceiver using the dielectric filter.
PRIOR ART
In a conventional dielectric filter of the kind referred to above, there are provided a plurality of resonators in a hexahedral rectangular dielectric unit. All of the six surfaces of the filter are substantially coated with an electrode film, and therefore, the filter does not require a shielding case or a mounting bracket, that is, the filter is able to be mounted on the surface of a circuit board. In the conventional structure as described above, since a plurality of resonators are provided in one dielectric block, many different kinds of molds must be provided if filters having different numbers of resonators are desired. More specifically, as the dielectric filter of this type is generally formed of ceramic material, the dielectric filter is manufactured by placing a ceramic material powder in a mold and baking the mold. Therefore, a different mold must be prepared for each type of filter to be manufactured, thus raising manufacturing costs. Moreover, since the distance between the resonators is determined by the size and shape of each mold, the degree of coupling between the resonators is hard to set.
In another example of a conventional dielectric filter of a comb line type, the degree of coupling of the resonators and the frequency of each resonator are interrelated as a function of the structure of the filter. One is changed when the other is changed, and each affects the other, and therefore, it is difficult to adjust the resonant frequency and the degree of coupling independently of each other.
In a further example of a known dielectric filter, a single resonator is provided in a single dielectric block which is coupled with another dielectric block having a resonator. Since a separate element is used to couple the dielectric blocks in this example, the structure is complicated and the number of parts is increased. This complicates manufacturing procedures and increases manufacturing costs.
Yet another known dielectric filter is composed of a plurality of dielectric bodies, each of which is provided with a resonator and bonded together to form a unit. The resonator used is a quarter-wave resonator wherein one end face is short-circuited and the other end face is open-circuited. Electromagnetic energy leaks from the open end face, leading to undesirable coupling of resonators. It is very difficult to achieve a predetermined degree of coupling with this structure. Further, a shielding cover to prevent undesired coupling with an external circuit is required. There is also a limit to the degree the transceiver can be miniaturized when this type of filter is employed.
SUMMARY OF THE INVENTION
A central object of the present invention is to provide a novel dielectric filter which can be easily manufactured to be compact in size, and with a variable number of resonators, which does not require a bracket or a shielding case and which does not require different molds for each resonator. It is a further object of the present invention to reduce the number of components and reduce manufacturing costs. It is a further object of the present invention to provide a filter wherein the resonant frequency of each resonator and the degree of coupling between resonators can be independently set or adjusted as desired.
A dielectric filter includes a first dielectric block having a through bore, substantially all of the surface area of the first dielectric block being covered with a conductive film to define a first dielectric resonator whose magnetic energy varies in the direction of an axis of the through bore. A first coupling window is formed in the conductive film on a first side surface for coupling an input signal applied thereto to the first dielectric resonator. A second coupling window is formed on a second side surface in a location wherein the magnetic energy in the first dielectric block is relatively high so that magnetic energy exits the first dielectric block via the second coupling window. A second dielectric block has a through bore and substantially all of the surface area of the second dielectric block is covered with a conductive film to define a second dielectric resonator. A third coupling window is formed on a first side surface of the second dielectric block at a location corresponding to the second coupling window such that magnetic energy leaving the first dielectric block via the second coupling window enters the second dielectric block via the third coupling window and sets up a magnetic field in the second dielectric block whose magnetic energy varies in the direction of the through bore of the second dielectric block. A fourth coupling window is formed on a second surface of the second dielectric block at a location where the resonant magnetic energy in the second dielectric block is relatively high such that magnetic energy leaves the second dielectric block via the fourth coupling window.
A transceiver according to the present invention can be miniaturized by using the dielectric filter of the present invention mentioned above.
REFERENCES:
patent: 4179673 (1979-12-01), Nishikawa et al.
patent: 5130683 (1992-07-01), Agahi-Kesheh et al.
patent: 5525946 (1996-06-01), Tsujiguchi et al.
patent: 5557246 (1996-09-01), Ishihara et al.
patent: 5737696 (1998-04-01), Yorita
patent: 0208424 (1987-01-01), None
patent: 64-000801 (1989-01-01), None
patent: 1-053601 (1989-03-01), None
patent: 2-050502 (1990-02-01), None
patent: 3-136402 (1991-06-01), None
patent: 4-150101 (1992-05-01), None
patent: 4-167701 (1992-06-01), None
Murata Manufacturing Co. Ltd.
Ostrolenk Faber Gerb & Soffen, LLP
Pascal Robert
Summons Barbara
LandOfFree
Dielectric filter having inductive coupling windows between... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Dielectric filter having inductive coupling windows between..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dielectric filter having inductive coupling windows between... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2613252