Integrated axial choke rotary offset parabolic reflector

• US 10,024,954 B1
• Filed: 11/01/2013
• Issued: 07/17/2018
• Est. Priority Date: 11/05/2012
• Status: Active Grant

• Current Assignee: the united states of america as represented by the secretary of the navy
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Adamski, Piotr Roman, Lauriente, Ferdinando Anthony
• Primary Examiner(s): Bythrow, Peter M
• Application Number:
  US13/987,236
• Time in Patent Office: 1,719 Days
• CPC Class Codes: G01S 7/027 Constructional details of housings, e.g. form, type, material or ruggedness
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems
• CPC Class Codes: H01Q 1/12 Supports; Mounting means
• CPC Class Codes: H01Q 1/125 Means for positioning
• CPC Class Codes: H01Q 1/1264 Adjusting different parts or elements of an aerial unit
• CPC Class Codes: H01Q 13/065 provided with a flange or a choke
• CPC Class Codes: H01Q 15/14 Reflecting surfaces; Equivalent structures electromagnetic shields H01Q1/526
• CPC Class Codes: H01Q 15/16 curved in two dimensions, e.g. paraboloidal
• CPC Class Codes: H01Q 3/02 using mechanical movement of antenna or antenna system as a whole
• CPC Class Codes: H01Q 3/04 for varying one co-ordinate of the orientation

Abstract

Antenna systems and methods employing an axial metallic corrugated choke ring attached to an offset reflector assembly and circumscribing (without contacting) a stationary metallic conical feed horn.

Claims

1. A rotary reflector antenna system, comprising:

a reflector plate;

an axial metallic corrugated choke ring having a plurality of concentric grooves formed on a cylindrical segment, with each concentric groove being formed between a pair of equal height and thickness corrugation ridges extending from said cylindrical segment, wherein said axial metallic corrugated choke ring has a first circular aperture;

a pair of support arms formed of non-metallic material;

a circular servo ring mounting bracket formed of non-metallic material defining a second circular aperture;

wherein said circular servo ring mounting bracket is attached to said reflector plate via said pair of support arms;

a circular choke ring mounting bracket formed of non-metallic material and defining a third circular aperture;

wherein said circular choke ring mounting bracket is disposed on top of said circular servo ring mounting bracket;

wherein said axial metallic corrugated choke ring is disposed on top of said circular choke ring mounting bracket such that said first circular aperture, said second circular aperture, and said third circular aperture centrally align vertically;

wherein said first circular aperture, said second circular aperture, and said third circular aperture form an orifice;

a stationary metallic conical feed horn disposed through said orifice such that said metallic conical feed horn is axially circumscribed by said axial metallic corrugated choke ring; and

wherein said metallic conical feed horn is not physically connected to said axial metallic corrugated choke ring;

wherein a number of said corrugation ridges is 3 to 6 per wavelength at F_low;

wherein a width of said corrugation ridges is within a range of 0.1*pitch to 0.2*pitch.

2. The rotary reflector antenna system of claim 1, wherein said number of said corrugation ridges is 5.

3. The rotary reflector antenna system of claim 2, wherein said width of said corrugation ridges is less than λ

/10, where λ

=c/F_low, where c=speed of light.

4. The rotary reflector antenna system of claim 3, wherein said circular servo ring mounting bracket has an inner diameter of about 3.785 inches, an outer diameter of about 5.5 inches, and a height/thickness of about 0.25 inches.

5. An antenna horn rotary reflector surface wave suppression method, comprising:

radiating from a metallic conical feed horn partially disposed through an orifice of an offset reflector assembly formed of a circular servo ring mounting bracket defining a first circular aperture, a circular choke ring mounting bracket stacked on top of said circular servo ring mounting bracket and defining a second circular aperture, an axial metallic corrugated choke ring disposed on top of said circular choke ring mounting bracket, at least two support arms connecting said circular servo ring mounting bracket to a reflector plate;

wherein said at least two support arms, said circular choke ring mounting bracket, and said servo ring mounting bracket are formed of non-metallic material;

wherein said axial metallic corrugated choke ring is formed of metallic material;

wherein said reflector plate is formed of metallic material deposited on a front face of said reflector plate;

wherein said first circular aperture is centered vertically in line with said second circular aperture and said first and second circular apertures form said orifice;

wherein said metallic conical feed horn is not physically connected to said offset reflector assembly;

wherein said axial metallic corrugated choke ring has a plurality of concentric grooves formed on a cylindrical segment, with each concentric groove being formed between a pair of equal height and thickness concentric corrugation ridges extending from said cylindrical segment;

rotating said offset reflector assembly about a phase center of said metallic conical feed horn while not moving said metallic conical feed horn; and

suppressing surface waves by forming overmoded coaxial waveguides using said axial metallic corrugated choke ring.

6. The method of claim 5, wherein said number of said corrugation ridges is 5.

7. The method of claim 6, wherein said width of said corrugation ridges is less than λ

/10, where λ

=c/F_low, where c=speed of light.

8. The method of claim 7, wherein said circular servo ring mounting bracket has an inner diameter of about 3.785 inches, an outer diameter of about 5.5 inches, and a height/thickness of about 0.25 inches.