Dipole arrays

• US 5,039,994 A
• Filed: 11/13/1989
• Issued: 08/13/1991
• Est. Priority Date: 12/20/1984
• Status: Expired due to Fees

• Current Assignee: Marconi Holdings Company Limited
• Original Assignee: Marconi Holdings Company Limited
• Inventors: Wash, Richard G., Woloszczuk, Edmund W.
• Primary Examiner(s): Wimer, Michael C.
• Application Number:
  US07/434,461
• Time in Patent Office: 638 Days
• Field of Search: 343/814-821, 343/807, 343/795, 343/853, 343/841, 343/813
• US Class Current: 343/813
• CPC Class Codes: H01Q 21/0075 Stripline fed arrays H01Q21/065 takes precedence
• CPC Class Codes: H01Q 21/062 using dipole aerials; H01Q21/067, H01Q21/068 take precedence
• CPC Class Codes: H01Q 9/065 Microstrip dipole antennas patch antenna H01Q9/0407

Abstract

An antenna formed by an array of dipole elements fed by a triplate or stripline system is provided with earthed posts between the dipoles. These posts prevent radiation from one dipole being received by others thereby improving the antenna efficiency.

Claims

1. An antenna comprising:

a coplanar array of dipoles tuned to electromagnetic signals of a given wavelength λ and

arranged with respect to orthogonal first, second and third directions in rows extending in the first direction and columns extending in the second direction,

a ground plane parallel to said first and second directions, each dipole being spaced in the third direction from said ground plane and having two poles which are aligned in the first direction, and

a plurality of individual parasitic conductive posts respectively disposed in the rows, the posts extending from said ground plane in said third direction a distance no greater than λ

/4 and being positioned so as to separate adjacent dipoles in each row, thereby to reduce mutual coupling between said dipoles, said posts having a length in said second direction which is less than λ

/2.

2. An antenna according to claim 1, further including a beam scanning means connected to said dipoles for controlling the relative phases of energy fed to different dipoles so as to scan a direction of maximum gain of said antenna.

3. An antenna as in claim 1, further comprising means for applying a signal of given frequency to said dipoles, said posts having lengths in said third direction tuned for said given frequency to minimize mutual coupling.

4. An antenna as in claim 1, wherein said posts have a length in said second direction which is less than λ

/4.

5. An antenna comprising:

an array of dipoles tuned to electromagnetic signals of a given wavelength λ and

disposed in an array plane, and arranged with respect to orthogonal first, second and third directions in rows extending in the first direction and columns extending in the second direction, each dipole having two poles which are aligned in the first direction,

a ground plane spaced in said third direction from said array plane, and

a plurality of separate parasitic, conductive posts respectively disposed in the rows, said posts extending from said ground plane toward said array plane in said third direction a distance no greater than λ

/4 and being positioned so as to separate adjacent dipoles in each row and form a means for absorbing and re-radiating at a low angle to said array plane some radiation emitted by said dipoles, thereby to reduce mutual coupling between said dipoles, said posts having a length in said second direction which is less than λ

/2.

6. An antenna as in claim 5, further comprising beam scanning means connected to said dipoles for controlling relative phases of energy fed to different ones of said dipoles so as to scan a direction of maximum gain of said antenna.

7. An antenna as in claim 5, further comprising means for applying a signal of given frequency to said dipoles, said posts having lengths in said third direction tuned for said given frequency to minimize mutual coupling.

8. An antenna as in claim 5, wherein said posts have a length in said second direction which is less than λ

/4.