Antenna

• US 20040004576A1
• Filed: 07/02/2002
• Published: 01/08/2004
• Est. Priority Date: 07/02/2002
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Anderson, Joseph M.
• Granted Patent: US 6,778,144 B2
• Time in Patent Office: Days
• US Class Current: 343/770
• CPC Class Codes: H01Q 13/106 Microstrip slot antennas patch antenna elements H01Q9/0407
• CPC Class Codes: H01Q 13/18 the slot being backed by, or formed in boundary wall of, a resonant cavity longitudinally slotted cylinder H01Q13/12 ; Open cavity antennas
• CPC Class Codes: H01Q 21/064 using horn or slot aerials slotted waveguides arrays H01Q21/005

Abstract

An antenna element (20) comprising a first conductive plane (22), a second conductive plane (24), and one or more dielectric layers (26, 28, 30) separating the first and second conductive planes (22 and 24). A resonant cavity (48) is formed by a portion of the first conductive plane (22), a portion of the second conductive plane (24) and electrical connections (e.g., plated vias(40)) extending therebetween. A slot (32) is formed in the portion of the second conductive plane (24) forming one side of the resonant cavity (48) and the feedline (34) extends into the cavity (48).

Claims

1. An antenna element comprising:

a first conductive plane;

a second conductive plane;

one or more dielectric layers separating the first and second conductive planes;

a resonant cavity formed by a portion of the first conductive plane, a portion of the second conductive plane, and electrical connections extending therebetween;

a slot in the portion of the second conductive plane forming the resonant cavity for coupling electromagnetic signals to or from the resonant cavity; and

a feedline extending into the resonant cavity.

2. An antenna element as set forth in claim 1, comprising two dielectric layers separating the first and second conductive planes and wherein the feedline is positioned between the two dielectric layers.

3. An antenna element as set forth in claim 2, further comprising a bonding layer between the two dielectric layers.

4. An antenna element as set forth in claim 1, wherein the electrical connections comprise a plurality of plated vias.

5. An antenna element as set forth in claim 1, wherein a coaxial connector has its central conductor connected to the feedline and its outer conductor connected to the first conductive plane.

6. An antenna element as set forth in claim 1, wherein dimensions of the cavity are selected so that the resonant cavity resonates at a frequency of about 44-45 Ghz.

7. An antenna element as set forth in claim 1, further comprising a radome layer adjacent the second conductive plane.

8. An antenna element as set forth in claim 1, wherein the slot has a cross-shape with two slot sections which centrally intersect.

9. An antenna as set forth in claim 8, wherein the electrical connections are arranged around the slot in a square with one open corner and wherein the feedline is aligned with the open corner.

10. An antenna as set forth in claim 9, wherein the slot sections are laterally aligned, respectively, between center points of opposite sides of the square.

11. An antenna as set forth in claim 10, wherein the feedline is transversely aligned with a center of the slot.

12. An antenna array incorporating a plurality of the antenna elements set forth in claim 1.

13. An antenna array comprising a two-by-two array of the antenna elements set forth in claim 1.

14. An antenna array comprising eight two-by-two arrays of the antenna elements set forth in claim 1.

15. A method of making an antenna array incorporating a plurality of the antenna elements set forth in claim 1, said method comprising the steps of stacking a plurality of boards and forming electrical connections therebetween.

16. A method as set forth in claim 15, wherein a first of the plurality of boards is made of a dielectric material and has a first conductive coating on one surface thereof forming the first conductive plane for each of the plurality of antenna elements;

wherein a second of the plurality of boards is made of a dielectric material and has a second conductive coating on one surface thereof forming the second conductive plane for each of the plurality of antenna elements;

wherein a plurality of slots are formed in the second conductive coating to form the slot for each of the plurality of antenna elements; and

wherein the second board has feedline circuitry formed on a surface opposite the surface forming the second conductive plane, the feedline circuitry forming the feedline for each of the plurality of antenna elements.

17. A method as set forth in claim 16, wherein said step of assembling the plurality of boards comprises placing a third board between the first and second boards, the third board being made of a bond film material and press bonding the boards together.

18. A method as set forth in claim 17, wherein said step of extending electrical connections comprises forming a set of plated vias between the first conductive coating and the second conductive coating for each of the plurality of antenna elements.

19. A method as set forth in claim 18, wherein said step of assembling the plurality of boards comprises placing a fourth board made of a radome-appropriate material adjacent the second board to form a radome layer for each of the plurality of antenna elements.

20. A method as set forth in claim 18, further comprising the step of connecting a central conductor of a coaxial connection to the feedline circuitry and connecting the outer conductor of the coaxial connection to the first conductive coating.

21. An antenna element as set forth in claim 1, wherein the cavity is sized to prevent excitation in the cavity mode.

22. An antenna element as set forth in claim 21, wherein the antenna generates circular polarization.