Broadband direct fed phased array antenna comprising stacked patches

• US 6,118,406 A
• Filed: 12/21/1998
• Issued: 09/12/2000
• Est. Priority Date: 12/21/1998
• Status: Expired due to Fees

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Josypenko, Michael J.
• Primary Examiner(s): Ho, Tan
• Application Number:
  US09/226,628
• Time in Patent Office: 631 Days
• Field of Search: 343/700 MS, 343/853, 343/846, 343/848, 343/815, 343/817, 343/829, 343/830
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
• CPC Class Codes: H01Q 5/371 Branching current paths
• CPC Class Codes: H01Q 5/378 Combination of fed elements with parasitic elements
• CPC Class Codes: H01Q 9/0414 in a stacked or folded configuration

Abstract

A broadband phased antenna is comprised of multiple patches which are dirly feed. The multiple patches provide the broadband patch antenna having overlapping narrow frequency bands and comprise a ground-plane element, multiple antenna elements, multiple dielectric layers, an RF feed line, and a feed arrangement. The ground-plane element has predetermined length and width dimensions and an aperture therein at a predetermined location near its center. The multiple antenna elements have an uppermost antenna element. The multiple dielectric layers are respectively interposed between and separate the multiple antenna elements into a stacked arrangement having odd and even numbered antenna elements.

Claims

1. A broadband antenna comprising:

a ground-plane element with predetermined length and width dimensions and having an aperture therein at a predetermined location near its center;

a plurality of antenna elements having an uppermost antenna element;

a plurality of dielectric layers respectively interposed between and separating said plurality of antenna elements into a stacked arrangement having alternating odd and even numbered antenna elements, and further separating said stacked arrangement from said ground-plane element, said stacked arrangement having an odd numbered element nearest said ground-plane element;

an RF feed line having an outer conductor and a center conductor, the feed line protruding through said aperture of said ground-plane element, said RF feed line extending upward to a feed point that is about half the distance between said ground-plane element and said uppermost antenna element; and

a feed arrangement having said outer conductor comprising a first bus and said center conductor comprising a second bus, said first bus being connected to said ground-plane element and to every even numbered antenna element and said second bus being connected to every odd numbered antenna element.

2. The broadband antenna of claim 1 wherein said ground-plane element and said plurality of antenna elements are comprised of copper.

3. The broadband antenna of claim 1 wherein said ground-plane element and said plurality of antenna elements each have a thickness of about 3 mils.

4. The broadband antenna of claim 1 wherein a plurality of dielectric layers each has a thickness of about 0.25 inches.

5. The broadband antenna of claim 1 wherein said ground-plane element has predetermined length and width dimensions of about 12 inches and about 12 inches respectively.

6. The broadband antenna of claim 1 wherein said antenna elements have edges and a centerline and said connections of said first and second busses are at the centerline of the edges of the antenna elements nearest said feed point.

7. A broadband antenna comprising:

a ground-plane element with predetermined length and width dimensions and having an aperture therein at a predetermined location near its center and comprised of an electrically conductive sheet having a first predetermined thickness;

a first dielectric layer having lesser length and width dimensions than said ground-plane and stacked thereon and having a second predetermined thickness;

a first antenna element having at least the same length and width dimensions as said first dielectric layer and stacked thereon and comprised of an electrically conductive sheet having a third predetermined thickness;

a second dielectric layer having lesser length and width dimensions than said first antenna element and stacked thereon and having a fourth predetermined thickness

a second antenna element having at least the same length and width dimensions as said second dielectric layer and stacked thereon and having a fifth predetermined thickness;

a third dielectric layer having lesser length and width dimensions than said second antenna element and stacked thereon and having a sixth predetermined thickness;

a third antenna element having at least the same length and width dimensions as said third dielectric layer and stacked thereon and having a seventh predetermined thickness; and

an RF feed line having an outer conductor and a center conductor, the feed line protruding through said aperture of said ground-plane element, said RF feed line extending upward from said feed point to a location of about half the distance between said ground-plane element and said third antenna element, said outer conductor having means for being electrically connected to said ground-plane element and to said second antenna element, said center conductor having means for being electrically connected to both said first and third antenna elements.

8. The broadband antenna of claim 7 wherein said first, second and third antenna elements have edges and a centerline and said means for electrically connecting to said first, second and third antenna elements are at the centerline of the edges of the first, second and third antenna elements nearest said feed point.

9. The broadband antenna of claim 7 wherein said electrically conductive sheets of said ground-plane element and said first, second and third elements are comprised of copper.

10. The broadband antenna of claim 7 wherein said first, third, fifth and seventh predetermined thicknesses are each 3 mils.

11. The broadband antenna of claim 7 wherein said second, fourth and sixth predetermined thicknesses are each 0.25 inches.

12. The broadband antenna of claim 7 wherein said ground-plane has predetermined length and width dimensions of about 12 inches and about 12 inches respectively.

13. The broadband antenna of claim 7 wherein said first antenna element has length and width dimensions of about 5.906 inches and about 5.906 inches respectively.

14. The broadband antenna of claim 7 wherein said second antenna element has length and width dimensions of about 5.5 inches and about 5.5 inches respectively.

15. The broadband antenna of claim 7 wherein said third antenna element has length and width dimensions of about 4.9 inches and about 4.9 inches respectively.

16. A method of providing a directly fed broadband antenna for a band of interest, the antenna having a ground-plane element, an aperture in a central region of the ground-plane element, a plurality of antenna elements each having dimensions that are selectable so that each antenna element resonates a selected resonant frequency, a plurality of dielectric layers and a feed line having an outer conductor and a center conductor, said outer conductor being directly connected to one of said plurality of antenna elements and said center conductor being directly connected to another one of said plurality of antenna elements and with all of said plurality of antenna elements being directly connected to one of said outer and center conductors, said plurality of antenna elements having lowermost and uppermost antenna elements and said plurality of dielectric layers respectively interposed between and separating said plurality of antenna elements into a stacked arrangement and further separating said stacked arrangement from the ground-plane element, the lowermost element of the stacked arrangement being nearest the ground-plane element, the uppermost element of the stacked arrangement being farthest from the ground-plane element, said method comprising the steps of:

selecting the dimensions of said lowermost antenna element so that its resonant frequency is at the bottom of said band of interest;

selecting the dimensions of a next antenna element nearest the ground-plane element so that its resonant frequency is greater than that of the lowermost antenna element but overlapping that of the lowermost antenna element and within a VSWR of less than 1.5; and

iteratively selecting the dimensions of succeeding next antenna element nearest the ground-plane element so that its resonant frequency is greater than but overlapping that of the next antenna element nearest to the ground-plane element and within a VSWR of less than 1.5 until the band of interest has been covered.

17. The method of claim 16 wherein said plurality of antenna elements and said plurality of dielectric layers are selected to be of a number of at least three.

18. The method of claim 17 wherein said resonant frequencies of said antenna elements are selected so as to overlap within a VSWR of less than 4.0.

19. The method of claim 16 further comprising the step of arranging said feed line to be about half-way between said ground-plane element and said uppermost antenna element.