Coaxial line to double ridge waveguide transition

• US 4,144,506 A
• Filed: 09/23/1977
• Issued: 03/13/1979
• Est. Priority Date: 09/23/1977
• Status: Expired due to Term

• Current Assignee: Litton Systems Incorporated
• Original Assignee: Litton Systems Incorporated
• Inventors: McCammon, John W., Imokawa, George
• Primary Examiner(s): Gensler, Paul L.
• Application Number:
  US05/835,878
• Time in Patent Office: 536 Days
• Field of Search: 333/21 R, 333/26, 333/33
• US Class Current: 333/26
• CPC Class Codes: H01P 5/103 Hollow-waveguide/coaxial-line transitions

Abstract

A novel structure in a coaxial to waveguide transmission line transition includes a waveguide section having longitudinally extending ridges on two opposed walls; a metal impedance transition member extending from one wall of the waveguide having a geometry within the waveguide of three right cylinders of dissimilar size stacked upon one another to form a steplike arrangement and a central passage therethrough; a dielectric cylindrical member extends into said waveguide from an opening in a waveguide wall opposed to that of the transition member and is in abutting relationship with the end of said impedance transition member; an elongate rodlike conductor extends axially through said dielectric member and said impedance transition; further each of the longitudinally extending waveguide ridges includes an outwardly flared portion of increasing width, one of which abuts the periphery of the lower step of said transition member and the other of which is spaced a predetermined distance from said dielectric member to define a gap; and a waveguide cavity is formed on one side of said impedance transition member and a positionable shorting wall borders one side of said cavity.

Claims

1. A coaxial line to ridged rectangular waveguide transition for coupling microwave energy comprising:

(a) a rectangular waveguide section of metal material containing first and second ends, top, bottom and side walls defining a hollow interior, and an end wall at or approximate said first end, longitudinally extending opposed first and second ridges of first and second predetermined length extending from said second end and located on the inner surfaces of the top and bottom walls, respectively, each of said ridges being of a predetermined short height, d₀,

each of said ridges containing an end section of relatively uniform rectanguloid section and a flared section of increasing with outwardly tapered with the latter section located remote from said second end;

(b) impedance transition means of metal material extending into the waveguide through one of said top and bottom walls, said transition means having a portion protruding within said waveguide interior, said protruding portion having a geometry which includes;

a first right cylindrical portion of radius, r₁, having a first axis and a height, d₁, slightly greater than the height, d_o, of said ridges;

a second right cylindrical portion of radius, r₂, having a second axis and a short height, d₂, located on top of and within the surface defined by said first cylindrical portion;

said second axis displaced from said first axis and said radius, r₂, being less than said radius, r_1;

and with an outer surface portion located most remote from said second waveguide end of said two cylindrical portions being tangent to a common plane orthogonal to the axis of said waveguide section along a common line in said plane;

a third right cylindrical portion having a radius, r₃, a third axis, and a height, d₃, located on top of and within the surface defined by said second cylindrical portion;

with said third axis being coaxial with said second axis and wherein said third radius, r₃, is smaller than said second radius, r₂ ;

the sum of the heights of said cylindrical portions within said waveguide interior, d₁ +d₂ +d₃, being less than the distance between said top and bottom walls of said waveguide section but greater than the distance between said opposed ridges;

a dielectric member pervious to microwave energy having a cylindrical portion extending into said waveguide section interior from an opposed wall thereof coaxially with said third cylindrical portion and abutting the end thereof;

an elongate rodlike conductor member extending through said dielectric member and into said cylindrical portions for conducting microwave energy into said waveguide section;

said first tapered ridge section containing a concavely cylindrical end periphery located in abutting relation with said first cylindrical portion;

said second tapered ridge section containing an end surface spaced from said third cylindrical portion by a slight distance and being spaced from said dielectric member by a slight distance; and

said dielectric member and said rodlike conductor member having an end geometry and relationship for coupling of a coaxial type connector.

2. The invention as defined in claim 1 wherein said impedance transition means includes a hollow cylindrical chamber coaxial with the axis of said third cylindrical portion and wherein said rodlike conductor member extends within said chamber and further comprising:

spring means located in said chamber for applying an axial biasing pushing force in said rodlike conductor member.

3. The invention as defined in claim 2 further including plug means for holding said spring means within said chamber.

4. The invention as defined in claim 1 wherein said end wall of said waveguide section is adjustably positionable.

5. The invention as defined in claim 1 wherein said end wall of said waveguide section is of a concave cylindrical geometry.