Dielectric image-resonator multiplexer

• US 4,881,051 A
• Filed: 08/03/1988
• Issued: 11/14/1989
• Est. Priority Date: 04/05/1988
• Status: Expired due to Fees

• Current Assignee: Com DEV Limited 155 Sheldon Drive Cambridge Ontario Canada N1R 7H6
• Original Assignee: Com Dev Limited (Honeywell International Inc.)
• Inventors: Tang, Wai-Cheung, Bryant, David M. T., Cameron, Richard J.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/227,788
• Time in Patent Office: 468 Days
• Field of Search: 333/110, 333/134, 333/135, 333/202, 333/208-212, 333/219, 333/219.1, 333/235, 333/227, 333/231, 333/248, 370/38, 370/123
• US Class Current: 333/208
• CPC Class Codes: H01P 1/2084 with dielectric resonators
• CPC Class Codes: H01P 1/2138 using hollow waveguide filters H01P1/2131 takes precedence
• CPC Class Codes: H01P 7/10 Dielectric resonators

Abstract

A two, three or four channel multiplexer can be operated in the TE₀₁δ or HE₁₁δ modes, each channel of the multiplexer has one bandpass filter, with each filter usually having a plurality of cavities. One cavity of each filter is a common cavity with all of the other filters of the multiplexer. The common cavity contains one independent dielectric quarter-cut or half-cut image resonator for each filter representing a channel of the multiplexer. Each resonator is mounted on a suitable support the common cavity provides a common junction and contains a loop coupling to couple electromagnetic energy between the various channels. The multiplexer has at least one input and at least one output. Previous microwave multiplexers have a plurality of bandpass filters arranged on a coaxial manifold. With the multiplexer of the present invention, the manifold can be eliminated. Further, at the S-band or L-band, substantial weight and volume savings can be achieved using the multiplexer of the present invention without sacrificing performance. This can be very important for space applications.

Claims

1. A multiplexer comprising two, three or four channels, each channel having one bandpass filter, each filter having at least one cavity, said at least one cavity of each filter being a common cavity with all of the other filters of the multiplexer, said common cavity containing one independent dielectric cut image resonator for each filter representing a channel of said multiplexer, each resonator being mounted on a suitable support, said common cavity providing a common junction and containing a means to couple electromagnetic energy between the various channels, said multiplexer having at least one input and at least one output.

2. A multiplexer as claimed in claim 1 wherein the means to couple electromagnetic energy between the various channels is a loop coupling located in the common channel.

3. A multiplexer as claimed in claim 2 wherein the independent dielectric cut image resonators are selected from the group of half-cut resonators and quarter-cut resonators.

4. A multiplexer as claimed in claim 3 wherein at least one filter in the multiplexer has a plurality of cavities.

5. A multiplexer as claimed in claim 4 wherein the common cavity contains one quarter-cut dielectric resonator for each filter representing a channel of the multiplexer.

6. A multiplexer as claimed in claim 4 wherein the independent dielectric cut image resonators are selected from the group of half-cut dielectric resonators and quarter-cut dielectric resonators but are mainly quarter-cut dielectric resonators.

7. A multiplexer as claimed in claim 2 wherein at least one filter has a plurality of cavities and has one cavity, other than the common cavity, containing a plurality of cut image resonators.

8. A multiplexer as claimed in claim 7 wherein the independent dielectric cut resonators in said one cavity are half-cut resonators.

9. A multiplexer as claimed in claim 7 wherein the independent dielectric cut resonators are quarter-cut resonators.

10. A multiplexer as claimed in claim 4 wherein the cavities have a rectangular cross-section, each cavity having walls formed of metal septae.

11. A multiplexer as claimed in claim 4 wherein a majority of the cavities have a square cross-section.

12. A multiplexer as claimed in any one of claims 2, 5 or 9 wherein the number of independent one quarter-cut resonators in a single cavity ranges from one to four.

13. A multiplexer as claimed in any one of claims 10 or 11 wherein electromagnetic energy is coupled between resonators at a common intersection of septae by coupling through apertures between adjacent cut resonators, said apertures being appropriately located in said septae.

14. A multiplexer as claimed in any one of claims 2, 5 or 10 wherein electromagnetic energy is coupled between independent one quarter-cut resonators of the same cavity, other than the common cavity, by proximity coupling.

15. A multiplexer as claimed in claim 10 wherein electromagnetic energy is coupled between resonators located at a common intersection of septae, but not immediately adjacent to one another by cross-coupling.

16. A multiplexer as claimed in claim 10 wherein, when it is desired to prevent proximity coupling between two independent one quarter-cut resonators that would otherwise be in the same cavity, an extra septum is inserted to divide what would otherwise by a square cavity in half into two rectangular cavities to prevent such proximity coupling.

17. A multiplexer as claimed in any one of claims 2, 5 or 10 wherein the filter resonates in a TE₀₁δ

mode.

18. A multiplexer as claimed in any one of claims 2, 5 or 10 wherein the filter resonates in a HE₁₁δ

mode.

19. A multiplexer as claimed in claim 10 wherein the multiplexer has two channels and seven cavities, with the total number of independent quarter-cut resonators being equal to eight, said cavities being arranged in a configuration of two large squares overlapping with one another at a common corner cavity, a first, second, third and fourth cavities forming one square and a fourth, fifth, sixth and seventh cavities forming a second square, said fourth cavity being the common cavity and containing the loop coupling, said fourth cavity containing two independent quarter-cut resonators with the remaining cavities of the multiplexer each containing one independent quarter-cut resonator, a first, second, third and fourth quarter-cut resonators being located at a common intersection of septae and being oriented in the form of a circle, a fifth, sixth, seventh, eighth dielectric resonator being located at a common intersection of septae and also being oriented in the form of a circle.

20. A multiplexer as claimed in claim 10 wherein the multiplexer has three channels and eight cavities, with the common cavity containing three independent quarter-cut dielectric resonators, the filter of one channel containing four independent dielectric quarter-cut resonators and four cavities including the common cavity, one resonator being located in each cavity other than the common cavity, a second filter containing four independent dielectric quarter-cut resonators and a total of three cavities, including the common cavity, one cavity other than the common cavity containing two independent quarter-cut resonators, a third filter also containing three cavities including the common cavity and having four quarter-cut resonators, there being two independent quarter-cut resonators in one cavity other than the common cavity.

21. A multiplexer as claimed in claim 10 wherein the multiplexer has three channels and nine cavities, with the common cavity containing three independent quarter-cut resonators, one for each channel, a first channel having four independent quarter-cut resonators in four cavities including the common cavity, there being one resonator per cavity other than the common cavity, except that one cavity other than the common cavity contains a quarter-cut resonator from the first channel together with a quarter-cut resonator from a second channel, the second channel having four independent quarter-cut resonators and four cavities including the common cavity, there being one resonator of the second channel in each of the four cavities, a third channel containing four independent quarter-cut dielectric resonators in four cavities including the common cavity, there being one resonator per cavity except for the common cavity.

22. A multiplexer as claimed in claim 10 wherein the multiplexer has three channels and eight cavities, a first channel containing a filter having three independent quarter-cut resonators and one independent half-cut resonator in a total of three cavities including the common cavity, there being one quarter-cut resonator and one half-cut resonator in one cavity other than the common cavity, a second channel containing a filter with four independent quarter-cut resonators in four cavities including the common cavity, there being one resonator of the second channel per cavity, a third channel containing a filter having three independent quarter-cut resonators and one independent half-cut resonator arranged in a manner similar to the first channel.

23. A multiplexer as claimed in claim 10 wherein the multiplexer has four channels and nine cavities, a first channel having a filter with four independent quarter-cut resonators in three cavities there being two quarter-cut resonators in one of the cavities other than the common cavity and one resonator of the first channel in each of the other two cavities including the common channel, a second channel containing four independent quarter-cut dielectric resonators in three cavities arranged in a manner similar to the first channel, a third channel containing four independent quarter-cut resonators in three cavities arranged in a manner similar to the first channel, a fourth channel containing four independent quarter-cut resonators in three cavities arranged in a manner similar to the first channel, there being four quarter-cut dielectric resonators in the common channel, said multiplexer having a total of sixteen quarter-cut dielectric resonators.

24. A multiplexer as claimed in claim 10 wherein the multiplexer has four channels, a first channel having four independent quarter-cut dielectric resonators in four cavities, there being one resonator of the first channel in each cavity, a second, third and fourth channel each having four independent quarter-cut dielectric resonators arranged in a manner similar to the resonators of the first channel, there being four quarter-cut dielectric resonators, one from each channel in the common cavity, said multiplexer having a total of thirteen cavities and sixteen quarter-cut dielectric resonators.

25. A multiplexer as claimed in any one of claims 3, 6 or 9 wherein the quarter-cut resonators are 45°

sectors.

26. A multiplexer as claimed in any one of claims 3, 6 or 8 wherein the half-cut resonators are 180°

sectors.