Wave transmission lines and networks – Coupling networks – Wave filters including long line elements
Reexamination Certificate
1999-06-30
2001-04-03
Lee, Benny (Department: 2817)
Wave transmission lines and networks
Coupling networks
Wave filters including long line elements
C333S230000, C333S212000
Reexamination Certificate
active
06211752
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to microwave filter devices having a metal cavity with dielectric inserts.
The invention is particularly advantageous when applied to filtering in the field of satellite telecommunications.
Metal cavities have long been used to filter microwaves.
Recent research has shown that loading such metal cavities with transverse inserts in the cavity is beneficial in improving the electrical performance of the resonators constituted by the metal cavities.
In this regard, reference may advantageously be had to the following publications:
[1] R. Comte, S. Verdeyme, P. Guillon, “New concept for low loss microwave devices”, Electronics Letters, Vol. 30, No. 5, Mar. 3, 1994, 1995 MTT-S Digest, Orlando, Vol. 3, pp 1535-1538;
[2] R. Comte, S. Verdeyme, P. Guillon, “Rigorous design of multimodal low losses microwave cavity”, ESA workshop on advanced CAD for microwave filters and passive devices, 1995, ESTEC, pp 225-231;
[3] R. Comte, S. Gendraud, S. Verdeyme, P. Guillon, C. Boschet, B. Theron, “A high Q factor microwave cavity”, 1995, MTT-S Digest, Orlando, Vol. 3, pp 1535-1538.
It might nevertheless still be thought today that, because of the distribution of the field in such cavities with dielectric inserts, they could be coupled to input and output waveguides only via metal coupling irises or coaxial probes on the side walls of the cavities and not on their end walls.
The dielectric inserts distance high electromagnetic fields from the metal end walls of the cavity and thereby confine the energy in the central part of the cavity.
The energy levels are therefore very low in the vicinity of the end walls of the cavity and this is why it might be thought that correct coupling could not be achieved via those walls.
However, a problem arises with coupling via the side walls of the cavity because of coupling of spurious resonant modes in the dielectric inserts, especially for high values of input coupling.
SUMMARY OF THE INVENTION
One aim of the invention is to propose a filter device having a metal cavity with dielectric inserts which solves the above problem and also has particularly satisfactory properties, in particular at high powers.
Because of the distribution of the field in such cavities with dielectric inserts, it might also be thought that it is not possible to couple to each other a plurality of resonators defined in the same metal cavity by a plurality of dielectric inserts.
Another aim of the invention is therefore to propose a metal cavity type device in which the dielectric inserts define a plurality of resonators enabling said device to effect multiple filtering and in which means are provided for coupling the resonators to each other.
The inventors have found that, unexpectedly, transverse metal irises in the end walls of the cavity or inside the cavity, between two resonators defined by dielectric inserts, provide particularly satisfactory coupling and solve the problem caused by coupling of spurious resonant modes in the dielectric inserts.
Accordingly, the invention proposes a filter device including a metal cavity closed by two end walls extending transversely relative to the axis of said cavity and at least two dielectric inserts defining a resonator in said cavity, characterized in that it includes at least one coupling iris which also extends transversely relative to said axis.
The device advantageously includes two coupling irises on respective end walls and which couple said cavity to metal waveguides on said end walls.
It can include a coupling iris extending transversely between two resonators each defined between two dielectric inserts.
REFERENCES:
patent: 3028565 (1962-04-01), Walker et al.
patent: 4721933 (1988-01-01), Schwartz et al.
patent: 5083102 (1992-01-01), Zaki
patent: 5703547 (1997-12-01), Bertin et al.
patent: 6005457 (1999-12-01), Wu
patent: 0 351 840 A3 (1990-01-01), None
Y. Kobayashi et al, “A Low Bandpass Filter Using Electrically Coupled High-Q TM01 Dielectric Rod Resonators”, IEEE Transactions On Microwave Theory and Techniques, vol. 36, No. 12, Dec. 19, 1988, pp. 1727-1732, XP000035419.
R. Comte et al, “Rigorous Design of a Multimodal Low Losses Microwave Cavity”, ESA Workshop On Advanced Cad for Microwave Filters and Passive Devices, Nov. 6-8 1995, pp. 225-231, XP000671423.
Gendraud Sandra
Guillon Pierre
Verdeyme Serge
Alcatel
Lee Benny
Lee Stephen E.
Sughrue Mion Zinn Macpeak & Seas, PLLC
LandOfFree
Filtering device with metal cavity provided with dielectric... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Filtering device with metal cavity provided with dielectric..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Filtering device with metal cavity provided with dielectric... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2463450