Multiband piston polarizer waveguide assembly including coaxially configured inner and outer waveguide cavities
Provided herein are various enhancements for radio frequency feed structures for waveguide-fed antenna systems. A waveguide structure includes an outer waveguide cavity comprising radial ports and an outer aperture, and disposed coaxially about a piston polarizer element housing an inner waveguide cavity. The piston polarizer element comprises longitudinal ridges. The inner waveguide cavity comprises an axial port and an inner aperture disposed coaxially with the outer aperture.
1 . A waveguide structure, comprising:
an outer waveguide cavity comprising radial ports and an outer aperture, and disposed coaxially about a piston polarizer element housing an inner waveguide cavity;
the piston polarizer element comprising longitudinal ridges; and
the inner waveguide cavity comprising an axial port and an inner aperture disposed coaxially with the outer aperture.
2 . The waveguide structure of claim 1 , wherein the piston polarizer element comprises the longitudinal ridges spaced 90 degrees radially apart, with a first two of the longitudinal ridges having a length shorter than a second two of the longitudinal ridges.
3 . The waveguide structure of claim 1 , wherein the piston polarizer element is rotatable within the outer waveguide cavity with respect to the radial ports to alter polarization characteristics of radio frequency signals propagated by the outer waveguide cavity.
4 . The waveguide structure of claim 1 , comprising:
a feed structure having a plurality of waveguide ports having generally rectangular cross-sectional configurations; and
wherein the feed structure is configured to couple the plurality of waveguide ports to the axial port of the inner waveguide cavity having a generally circular cross-sectional configuration.
5 . The waveguide structure of claim 1 , comprising:
a magic tee element having a difference port, a sum port, and colinear ports coupled by recombination arms to the radial ports of the outer waveguide cavity.
6 . The waveguide structure of claim 5 , wherein the inner waveguide cavity is configured to propagate radio frequency energy of a first frequency range among the inner aperture and the axial port; and
wherein the outer waveguide cavity is configured to propagate radio frequency energy of a second frequency range between the outer aperture and the radial ports.
7 . The waveguide structure of claim 5 , wherein the magic tee element comprises:
an impedance matching element comprising a triangular body disposed in a waveguide cavity of the magic tee element and protruding perpendicularly from a wall of the waveguide cavity of the magic tee between the colinear ports.
8 . The waveguide structure of claim 5 , wherein the sum port of the magic tee element comprises a rectangular cross-sectional configuration, and the colinear ports and the difference port each comprise pentagonal cross-sectional configurations establishing steeples having two sides shorter than remaining sides.
9 . The waveguide structure of claim 5 , comprising a monolithic structure comprising the magic tee element, the recombination arms, and the piston polarizer element.
10 . An assembly, comprising:
a polarizer portion comprising:
an outer waveguide cavity comprising radial ports and an outer aperture, and disposed coaxially about a piston polarizer element housing an inner waveguide cavity;
the piston polarizer element comprising longitudinal ridges; and
the inner waveguide cavity comprising an axial port and an inner aperture disposed coaxially with the outer aperture; and
a magic tee portion comprising:
a difference port, a sum port, and colinear ports; and
a magic tee waveguide cavity housing an impedance matching element; and
recombination arms coupling the collinear ports of the magic tee portion to the radial ports of the polarizer portion.
11 . The assembly of claim 10 formed using an additive manufacturing technique into a monolithic workpiece.
12 . The assembly of claim 10 , wherein the piston polarizer element comprises the longitudinal ridges spaced 90 degrees radially apart, with a first two of the longitudinal ridges having a length shorter than a second two of the longitudinal ridges.
13 . The assembly of claim 10 , wherein the piston polarizer element is rotatable within the outer waveguide cavity with respect to the radial ports to alter polarization characteristics of radio frequency signals propagated by the outer waveguide cavity.
14 . The assembly of claim 10 , wherein the inner waveguide cavity is configured to propagate radio frequency energy of a first frequency range among the inner aperture and the axial port; and
wherein the outer waveguide cavity is configured to propagate radio frequency energy of a second frequency range between the outer aperture and the radial ports.
15 . The assembly of claim 10 , wherein the impedance matching element comprises an isosceles right triangular body and protruding perpendicularly from a wall of the magic tee waveguide cavity between the colinear ports.
16 . The assembly of claim 10 , wherein the sum port of the magic tee portion comprises a rectangular cross-sectional configuration, and the colinear ports and the difference port each comprise pentagonal cross-sectional configurations establishing steeples having two sides shorter than remaining sides.
17 . The assembly of claim 10 , comprising:
a feed structure having a plurality of waveguide ports having generally rectangular cross-sectional configurations; and
wherein the feed structure is configured to couple the plurality of waveguide ports to the axial port of the inner waveguide cavity having a generally circular cross-sectional configuration.
18 . A method, comprising:
forming a polarizer portion comprising:
an outer waveguide cavity comprising radial ports and an outer aperture, and disposed coaxially about a piston polarizer element housing an inner waveguide cavity;
the piston polarizer element comprising longitudinal ridges; and
the inner waveguide cavity comprising an axial port and an inner aperture disposed coaxially with the outer aperture; and
forming a magic tee portion comprising:
a difference port, a sum port, and colinear ports; and
a magic tee waveguide cavity housing an impedance matching element; and
forming recombination arms coupling the collinear ports of the magic tee portion to the radial ports of the polarizer portion.
19 . The method of claim 18 , wherein the piston polarizer element comprises the longitudinal ridges spaced 90 degrees radially apart, with a first two of the longitudinal ridges having a length shorter than a second two of the longitudinal ridges; and
wherein the impedance matching element comprises an isosceles right triangular body and protruding perpendicularly from a wall of the magic tee waveguide cavity between the colinear ports.
20 . The method of claim 18 , comprising:
forming a monolithic structure comprising the polarizer portion, the magic tee portion, and the recombination arms using an additive manufacturing technique.