Low loss waveguide launch

• US 20040036550A1
• Filed: 08/20/2002
• Published: 02/26/2004
• Est. Priority Date: 08/20/2002
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Heidinger, Richard Dennis, Emrick, Rudy Michael
• Granted Patent: US 6,917,256 B2
• Time in Patent Office: Days
• US Class Current: 333/26
• CPC Class Codes: H01P 5/107 Hollow-waveguide/strip-line transitions

Abstract

According to the preferred exemplary embodiments of the present invention, a transmission line, such as microstrip, is connected to a waveguide using suspended stripline as an intermediate connection. This method results is a very low-loss transition, suitable for active microwave device applications such as low-noise receivers and transmitting devices such as power amplifiers.

Claims

1. A coupling apparatus comprising:

a microstrip transmission line;

a suspended stripline connected to said microstrip transmission line; and

a waveguide connected to said suspended stripline.

2. The coupling apparatus of claim 1 wherein said microstrip transmission line comprises:

a groundplane;

a substrate mounted on said groundplane; and

a conductor strip mounted on said substrate.

3. The coupling apparatus of claim 2 wherein said substrate comprises a Teflon®

substrate.

4. The coupling apparatus of claim 2 wherein said substrate comprises a Duroid®

substrate.

5. The coupling apparatus of claim 2 wherein said waveguide further comprises a depth guide inserted during an assembly process.

6. The coupling apparatus of claim 1 wherein said suspended stripline comprises:

a groundplane;

a dielectric slab mounted within said groundplane; and

a conductor strip mounted on said dielectric slab.

7. The coupling apparatus of claim 2 wherein said dielectric slab comprises a Teflon®

substrate.

8. The coupling apparatus of claim 2 wherein said dielectric slab comprises a Duroid®

substrate.

9. The coupling apparatus of claim 1 wherein said waveguide further comprises:

a backshort; and

an opening for receiving at least a portion of said suspended stripline.

10. The coupling apparatus of claim 1 wherein said microstrip transmission line transmits a signal to said waveguide via said suspended stripline.

11. The coupling apparatus of claim 10 wherein said signal comprises a microwave signal with a frequency greater than 1 GHz.

12. The coupling apparatus of claim 10 wherein said signal comprises a microwave signal with a frequency greater than 25 GHz.

13. A low-loss waveguide launch comprising:

a microstrip section, said microstrip section comprising;

a microstrip groundplane;

a microstrip substrate mounted on said microstrip groundplane; and

a microstrip conductor strip mounted on said microstrip substrate;

a suspended stripline section connected to said microstrip transmission line, said suspended stripline section comprising;

a stripline groundplane;

a stripline substrate mounted within said stripline groundplane; and

a stripline conductor strip mounted on said stripline substrate;

a waveguide, said waveguide comprising;

an opening for receiving at least a portion of said stripline; and

a backshort; and

;

wherein said waveguide receives at least a portion of said suspended stripline conductor strip and said stripline substrate through said opening in said waveguide.

14. The waveguide launch of claim 13 wherein said microstrip conductor strip and said stripline conductor strip form a contiguous transmission line.

15. The waveguide launch of claim 13 wherein said microstrip conductor strip transmits a signal to said waveguide via said stripline conductor strip.

16. The waveguide launch of claim 15 wherein said signal comprises a microwave signal with a frequency less than 1 GHz.

17. The waveguide launch of claim 15 wherein said signal comprises a microwave signal with a frequency greater than 1 GHz.

18. The waveguide launch of claim 15 wherein said signal comprises a microwave signal with a frequency greater than 25 GHz.

19. A method comprising the steps of:

connecting a microstrip transmission line to a suspended stripline;

connecting said suspended stripline to a waveguide; and

transmitting a signal from said microstrip transmission line to said waveguide via said suspended stripline.

20. The method of claim 19 further comprising the step of positioning at least a portion of said suspended stripline within said waveguide using a depth guide.

21. The method of claim 19 wherein said step of transmitting a signal comprises the step of transmitting a microwave signal with a frequency less than 1 GHz.

22. The method of claim 19 wherein said step of transmitting a signal comprises the step of transmitting a microwave signal with a frequency greater than 1 GHz.

23. The method of claim 19 wherein said step of transmitting a signal comprises the step of transmitting a microwave signal with a frequency greater than 25 GHz.

24. The method of claim 19 wherein said suspended stripline comprises:

a groundplane;

a dielectric slab mounted within said groundplane; and

a conductor strip mounted on said dielectric slab.

25. The method of claim 19 wherein said microstrip transmission line comprises:

a groundplane;

a substrate mounted on said groundplane; and

a conductor strip mounted on said substrate.

26. The method of claim 19 wherein said waveguide further comprises;

an opening for receiving at least a portion of said suspended stripline; and

a backshort.