# US 2013/0278352 A1 · Ortho-mode transducer with wide bandwidth branch port

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- Number: US 2013/0278352 A1
- Document ID: US20130278352A1
- Status: Published application
- Kind: A1
- Application number: 13/453,913
- Filed: 2012-04-23
- Published: 2013-10-24
- Earliest claimed: 2012-04-23
- Assignees: Optim Microwave, Inc.
- Inventors: John P. Mahon; Cynthia P. Espino
- Web page: https://patentgrep.com/patent/US20130278352A1

## CPC

- H01P 1/161: sustaining two independent orthogonal modes, e.g. orthomode transducer {(combining or separating polarisations and frequencies H01P1/2131)}
- H01P 1/213: combining or separating two or more different frequencies (H01P1/215 takes precedence)
- H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B)

## Abstract

An ortho-mode transducer may include a cylindrical common waveguide terminating in a common port, a rectangular vertical branch waveguide in-line with the cylindrical common waveguide and terminating in a vertical port, and a rectangular horizontal branch waveguide normal to the common waveguide and terminating in a horizontal port. The vertical branch waveguide may be configured to couple a first linearly polarized mode from the vertical port to the common waveguide. The horizontal branch waveguide may be configured to couple a second linearly polarized mode, orthogonal to the first linearly polarized mode, from the horizontal port to the common waveguide. A portion of the vertical branch waveguide may overlap a portion of the cylindrical common waveguide. A septum may span the vertical branch waveguide proximate to the overlapping portions of the vertical branch waveguide and the common waveguide. A rectangular symmetry cavity may be opposed to the horizontal branch waveguide.

## Claims

### Claim 1

An ortho-mode transducer comprising:
a cylindrical common waveguide terminating in a common port;
a generally rectangular vertical branch waveguide in-line with the cylindrical common waveguide, the vertical branch waveguide terminating in a vertical port opposed to the common port, the vertical branch waveguide configured to couple a first linearly polarized mode from the vertical port to the common waveguide, a portion of the vertical branch waveguide overlapping a portion of the cylindrical common waveguide;
a septum spanning a long dimension of the vertical branch waveguide proximate to the overlapping portions of the vertical branch waveguide and the common waveguide;
a generally rectangular horizontal branch waveguide normal to the common waveguide and the vertical branch waveguide, the horizontal branch waveguide terminating in a horizontal port, the horizontal branch waveguide configured to couple a second linearly polarized mode from the horizontal port to the common waveguide, the second linearly polarized mode orthogonal to the first linearly polarized mode; and
a generally rectangular symmetry cavity opposed to the horizontal branch waveguide.

### Claim 2 (depends on 1)

The ortho-mode transducer of claim 1, wherein the horizontal branch waveguide comprises:
a first horizontal branch waveguide segment terminating in the horizontal port;
a third horizontal branch waveguide segment coupled to the common waveguide; and
a second horizontal branch waveguide segment coupled between the first horizontal branch waveguide segment and the third horizontal branch waveguide segment.

### Claim 3 (depends on 2)

The ortho-mode transducer of claim 2, wherein
a cross-sectional shape of the third horizontal branch waveguide segment is contained within a cross-sectional shape of the second horizontal branch waveguide segment, and
the cross-sectional shape of the second horizontal branch waveguide segment is contained within a cross-sectional shape of the first horizontal branch waveguide segment.

### Claim 4 (depends on 3)

The ortho-mode transducer of claim 3, wherein one or more of the first, second, and third horizontal branch waveguide segments is a ridged waveguide.

### Claim 5 (depends on 1)

The ortho-mode transducer of claim 1, wherein the symmetry cavity comprises:
a first symmetry waveguide segment terminating in a symmetry port;
a second symmetry waveguide segment coupled between the first symmetry waveguide segment and the common waveguide; and
a shorting plate closing the symmetry port.

### Claim 6 (depends on 5)

The ortho-mode transducer of claim 5, wherein
a cross-sectional shape of the second symmetry waveguide segment is contained within a cross-sectional shape of the first symmetry waveguide segment.

### Claim 7 (depends on 2)

The ortho-mode transducer of claim 2, wherein one or both of the first and second symmetry waveguide segments is a ridged waveguide.