Dual-band electromagnetic coupler

• US 6,577,207 B2
• Filed: 10/05/2001
• Issued: 06/10/2003
• Est. Priority Date: 10/05/2001
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Volman, Vladimir
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): Takaoka, Dean
• Application Number:
  US09/971,428
• Publication Number:
  US 20030067367A1
• Time in Patent Office: 613 Days
• Field of Search: 333/110, 333/126, 333/135, 333/113, 333/111, 333/137, 333/202, 333/108, 333/114, 333/122, 333/125, 333/157, 333/21.A
• US Class Current: 333/125
• CPC Class Codes: H01P 1/16 for mode selection, e.g. mode suppression or mode promotion; for mode conversion
• CPC Class Codes: H01P 1/172 using a dielectric element

Abstract

A coupler couples signal by way of a cluster of four square waveguide ports at a high frequency band, or by way of a two ridged waveguide ports at a lower frequency band, to a common square port. The coupling path includes a branch coupler for combining the TE_2,0 and TE_0,2 high-band signals from the square ports with the TE_1,0 low-band signals from the two ridged ports. The branch coupler is coupled to a mode converter or transformer, which allows the TE_2,0 and TE_0,2 mode signals to pass through unchanged, and which converts the TE_1,0 mode signals from the two ridged ports to TE_1,0, TE_0,1 in a square port. A ridged square waveguide section couples the square port of the mode converter to the common square port. The ridged square waveguide section includes ridges and phase shifters which delay components of the high-band modes to produce TE_1,0 and TE_0,1 modes at the common port in both bands.

Claims

1. A coupler with mode transformer, for coupling (a) a common square waveguide port supporting at least one of two mutually spatially orthogonal linear polarizations with at least one of nominally mutually independent (b) first external and (c) second external ports, said first external port being in the form of a cluster of first, second, third, and fourth clustered square waveguide ports, any one of which is capable of supporting at least one of two mutually spatially orthogonal linear polarizations, and said second external port being in the form of first and second rectangular ridged waveguide ports, each of which is capable of supporting a single linear polarization, said coupler comprising:

a ridged square waveguide section defining a first port coupled to said common square waveguide port and also defining a second port, said ridged square waveguide section including first and second mutually spatially orthogonal ridge structures lying between said first and second ports of said ridged square waveguide section, which ridge structures tend to concentrate the fields of either of two mutually spatially orthogonal linear polarizations in a region near the center of said ridged square waveguide section, said ridged square waveguide section also including first and second planar phase shifters, said first planar phase shifter lying parallel to said first ridge structure, and said second planar phase shifter lying parallel with said second ridge structure, so that said first and second planar phase shifters are mutually orthogonal, each of said first and second planar phase shifters being located between that one of said ridge structures with which it is parallel and a side wall of said ridged square waveguide section, for propagating a polarization distribution having a maximum near said center of said ridged square waveguide section from said first port to said second port of said ridged square waveguide section without substantial effect, and for delaying by substantially π

a spatial portion of electromagnetic modes propagating therein having distribution maxima near said phase shifters;

a transition section of waveguide, said transition section of waveguide defining a first square waveguide port which is coupled to said second port of said ridged square waveguide section, said transition section of waveguide including a first septum extending completely across said square cross-section at said second port of said transition section of waveguide to thereby define first and second internal rectangular waveguide ports, said first septum progressively reducing in size toward said first square waveguide port of said transition section of waveguide, said transition section of waveguide being for converting between electromagnetic modes at said first port having components parallel with said septum and electromagnetic modes at said first and second internal rectangular waveguide ports which have field distributions orthogonal to the narrow sides of said first and second rectangular waveguide ports of said transition section; and

an eight-port waveguide branch section defining said first and second rectangular ridged waveguide ports of said second nominally independent port of said coupler, said first, second, third, and fourth clustered square waveguide ports of said first nominally independent port of said coupler, and third and fourth internal rectangular waveguide ports having a common wall, said third and fourth internal rectangular waveguide ports of said branch section being coupled to said first and second internal rectangular waveguide ports of said transition waveguide section, said branch section further defining first and second H-plane walls parallel with said common wall, a first E-plane rectangular aperture in said first H-plane wall which is coupled to said first rectangular waveguide port of said second nominally independent port of said coupler, and a second rectangular aperture in said second H-plane wall which is coupled to said second rectangular waveguide port of said second nominally independent port of said coupler, said branch section further including a second septum extending from that edge of said first rectangular aperture which is adjacent said first nominally independent waveguide port to said first nominally independent waveguide port, to thereby aid in defining said first and second clustered square waveguide ports, and further including a third septum extending from that edge of said second rectangular aperture which is adjacent said first nominally independent waveguide port to said first nominally independent waveguide port, to thereby aid in defining said third and fourth clustered square waveguide ports.

2. A coupler with mode transformer, for coupling (a) a common square waveguide port supporting at least one of two mutually spatially orthogonal linear polarizations with at least one of nominally mutually independent (b) first external and (c) second external ports, said first external port being in the form of a cluster of first, second, third, and fourth clustered square waveguide ports, any one of which is capable of supporting at least one of two mutually spatially orthogonal linear polarizations, and said second external port being in the form of first and second rectangular ridged waveguide ports, each of which is capable of supporting a single linear polarization, said coupler comprising:

a ridged square waveguide section defining a first port coupled to said common square waveguide port and also defining a second port, said ridged square waveguide section including first and second mutually spatially orthogonal ridge structures lying between said first and second ports of said ridged square waveguide section, which ridge structures tend to concentrate the fields of the dominant TE_1,0 mode of either of said two mutually spatially orthogonal linear polarizations in a region near the center of said ridged square waveguide section, said ridged square waveguide section also including first and second planar phase shifters, said first planar phase shifter lying parallel to said first ridge structure, and said second planar phase shifter lying parallel with said second ridge structure, so that said first and second planar phase shifters are mutually orthogonal, each of said first and second planar phase shifters being located between that one of said ridge structures with which it is parallel and a side wall of said ridged square waveguide section, for propagating either polarization of said dominant TE_1,0 mode from said first port to said second port of said ridged square waveguide section without substantially affecting said dominant TE_1,0 mode, and for delaying by substantially π

a spatial portion of one of (a) a TE₂₀ and (b) a TE_0,2 mode propagating therein, to thereby convert between said dominant TE_1,0 mode at said first port of said square waveguide section and said one of sai (a) TE₂₀ and (b) TE_0,2 mode at said second port of said square waveguide section;

a transition section of waveguide, said transition section of waveguide defining a first square waveguide port which is coupled to said second port of said ridged square waveguide section, said transition section of waveguide including a first septum extending completely across said square cross-section at said second port of said transition section of waveguide to thereby define first and second internal rectangular waveguide ports, said first septum progressively reducing in size toward said first square waveguide port of said transition section of waveguide, said transition section of waveguide being for converting between said either polarization of said TE_1,0 mode at said second port of said ridged waveguide section and the TE_1,0 mode in said first and second internal rectangular ports of said transition section; and

an eight-port waveguide branch section defining said first and second rectangular ridged waveguide ports of said second nominally independent port of said coupler, said first, second, third, and fourth clustered square waveguide ports of said first nominally independent port of said coupler, and third and fourth internal rectangular waveguide ports having a common wall, said third and fourth internal rectangular waveguide ports of said branch section being coupled to said first and second internal rectangular waveguide ports of said transition waveguide section, said branch section further defining first and second H-plane walls parallel with said common wall, a first E-plane rectangular aperture in said first H-plane wall which is coupled to said first rectangular waveguide port of said second nominally independent port of said coupler, and a second rectangular aperture in said second H-plane wall which is coupled to said second rectangular waveguide port of said second nominally independent port of said coupler, said branch section further including a second septum extending from that edge of said first rectangular aperture which is adjacent said first nominally independent waveguide port to said first nominally independent waveguide port, to thereby aid in defining said first and second clustered square waveguide ports, and further including a third septum extending from that edge of said second rectangular aperture which is adjacent said first nominally independent waveguide port to said first nominally independent waveguide port, to thereby aid in defining said third and fourth clustered square waveguide ports.

3. A coupler according to claim 2, further comprising;

a first rectangular waveguide section extending from said first rectangular aperture to said first rectangular waveguide port of said second nominally independent port of said coupler;

a third ridge which extends through said first rectangular aperture on that side of said first rectangular aperture which is remote from said first nominally independent waveguide port, said ridge extending in contact with a wall of said first rectangular waveguide section at least part-way from said first rectangular waveguide aperture to said first rectangular waveguide port.

4. A coupler according to claim 3, wherein said third ridge extends, in contact with said first H-plane wall, from said first rectangular aperture toward said first rectangular internal port of said branch section.

5. A coupler according to claim 2, wherein said first rectangular aperture in said first H-plane wall of said branch section has at least one of height and width dimensions less than the corresponding dimension of said third internal rectangular waveguide port.

6. A coupler according to claim 2, wherein said second septum includes a tapered portion extending generally across, but not in contact with, said first rectangular aperture in said first H-plane wall, and in contact with said common wall of said third internal rectangular waveguide port.

7. A coupler according to claim 2, wherein said first ridge structure lying between said first and second ports of said ridged square waveguide section comprises first and second mutually coplanar ridge portions in electrical contact with mutually opposed walls of said ridged square waveguide section.

8. A coupler according to claim 7, wherein said first ridge structure lying between said first and second ports of said ridged square waveguide section further comprises a third planar ridge portion coplanar with said first and second mutually coplanar ridge portions, which third planar ridge portion is centered in said ridged square waveguide section and not in electrical contact with any wall of said ridged square waveguide section.

9. A coupler according to claim 8, wherein said third planar ridge portion is supported by a dielectric support structure.

10. A coupler according to claim 2, wherein said planar phase shifter comprises a dielectric plate.