Transmission line transition
A circuit structure may include first and second transmission lines having coupled center conductors. In the first transmission line, the center conductor may be between first and second spaced-apart extended conducting surfaces, with the space between the first and second conducting surfaces forming a cavity. An example of the first transmission line is a slabline. One or more of the second transmission lines may each be coaxial transmission lines having an outer conductor substantially surrounding the associated center conductor. The center conductor of each second transmission line may be coupled to and extend orthogonally of the center conductor of the first transmission line. In some examples, the outer conductor may extend between the center conductor of the associated second transmission line and the cavity.
1 . A circuit structure comprising:
a first transmission line having a first center conductor between first and second spaced-apart extended conducting surfaces, with the space between the first and second conducting surfaces forming a first cavity; and
one or more second coaxial transmission lines having a second center conductor and a third conductor substantially surrounding the second center conductor, each second center conductor extending orthogonally of the first center conductor and having an end coupled to an end of the first center conductor, each third conductor extending at least to a point between the second center conductor and the cavity.
2 . The circuit structure of claim 1 , further comprising a plurality of the second transmission lines, and a first intermediate conductor connected to each second center conductor and coupling the second center conductors to the first center conductor, the second center conductors extending in a common plane from the intermediate conductor.
3 . The circuit structure of claim 2 , of which the first center conductor has a first size, each second center conductor has a second size different than the first size, and the intermediate conductor has a third size between the first and second sizes.
4 . The circuit structure of claim 2 , of which the second center conductors are distributed equiangularly about the intermediate conductor.
5 . The circuit structure of claim 2 , of which the intermediate conductor has a center aligned with a center of the cavity between the first and second conducting surfaces, the first and second conducting surfaces are spaced apart a first width, and the periphery of each third conductor extends substantially to within one half of the first width of the center of the intermediate conductor.
6 . The circuit structure of claim 2 , further comprising a second cavity extending around the intermediate conductor and away from the first conductor beyond the third conductors.
7 . The circuit structure of claim 1 , of which each third conductor extends at least in line with the cavity.
8 . A circuit structure comprising:
a first transmission line having a first center conductor between first and second spaced-apart extended conducting surfaces, with the space between the first and second conducting surfaces forming a first cavity;
an intermediate conductor connected to an end of the first center conductor adjacent to an end of the cavity; and
a plurality of coaxial transmission lines, each coaxial transmission line having a second center conductor and a third conductor substantially surrounding the second center conductor, each second center conductor extending orthogonally of the first center conductor and having an end connected to the intermediate conductor.
9 . The circuit structure of claim 8 , of Which the first center conductor has a first size, each second center conductor has a second size different than the first size, and the intermediate conductor has a third size between the first and second sizes.
10 . The circuit structure of claim 8 , of which the second center conductors are distributed equiangularly about the intermediate conductor.
11 . The circuit structure of claim 10 , of which the first and second conducting surfaces are planar and parallel, and the second center conductors are distributed symmetrically about a plane parallel to the conducting surfaces and centered between the conducting surfaces.
12 . The circuit structure of claim 8 , of which the intermediate conductor has a center aligned with a center of the cavity between the first and second conducting surfaces, the first and second conducting surfaces are spaced apart a first width, and the periphery of each third conductor extends substantially to within one half of the first width of the center of the intermediate conductor.
13 . The circuit structure of claim 8 , of which each third conductor extends at least in line with the cavity.
14 . The circuit structure of claim 8 , further comprising a second cavity extending around the intermediate conductor and away from the first conductor beyond the third conductors.
15 . A circuit structure comprising:
a first slabline having a first center conductor surrounded by a shield defining a cavity and having first and second extended, spaced-apart parallel primary conducting surfaces, the first center conductor having a circular cross section with a first radius of curvature;
an intermediate conductor connected to an end of the first center conductor adjacent to an end of the cavity; and
a plurality of square coaxial transmission lines, each coaxial transmission line having a second center conductor connected to the intermediate conductor and extending orthogonally of the first center conductor, and a third conductor substantially surrounding the second center conductor and having four sides extending toward the intermediate conductor to a position in line with the cavity between the first and second conducting surfaces, the second center conductors being distributed equiangularly about the intermediate conductor.