Combined antenna, antenna array and method for using the antenna array

• US 9,705,198 B2
• Filed: 01/17/2012
• Issued: 07/11/2017
• Est. Priority Date: 01/17/2012
• Status: Active Grant

• Current Assignee: Saab AB
• Original Assignee: Saab AB
• Inventors: Ellgardt, Anders
• Primary Examiner(s): Phan, Dao
• Application Number:
  US14/372,954
• Publication Number:
  US 20150102962A1
• Time in Patent Office: 2,002 Days
• Field of Search: 342368, 342369, 342426, 342371, 342372, 343722, 343793, 343795, 343700 MS
• CPC Class Codes: G01S 13/10 using transmission of interrupted, pulse modulated waves determination of distance by phase measurement G01S13/32
• CPC Class Codes: G01S 2013/0245 Radar with phased array antenna
• CPC Class Codes: H01Q 21/00 Antenna arrays or systems arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system H01Q3/00
• CPC Class Codes: H01Q 21/062 using dipole aerials; H01Q21/067, H01Q21/068 take precedence
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H01Q 3/34 by electrical means active lenses or reflecting arrays H01Q3/46
• CPC Class Codes: H01Q 9/16 with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole H01Q9/44 takes precedence

Abstract

An antenna including a dipole antenna element having central feeding points, a common mode rejection filter, a first length of a two-conductor transmission line, and a common mode rejection filter arranged and connected between a far end of the first length of the two-conductor transmission line and the feeding points of the dipole antenna element. The first length of the two-conductor transmission line is arranged to extend from a ground plane to a first height where the first length of the two-conductor transmission line is connected to the common mode rejection filter.

Claims

1. An antenna, comprising:

a dipole antenna element having central feeding;

a common mode rejection filter,

a first length of a two-conductor transmission line, and

a common mode rejection filter arranged and connected between a far end of the first length of the two-conductor transmission line and the feeding points of the dipole antenna element,

wherein the first length of the two-conductor transmission line is arranged to extend from a ground plane to a first height where the first length of the two-conductor transmission line is connected to the common mode rejection filter, and a second length of transmission line arranged to make a connection between the filter and the dipole and to enable placement of the dipole on a second height above the ground plane regardless of a physical dimension of the filter and the first height.

2. The antenna according to claim 1, wherein the dipole is arranged and connected directly on top of the filter.

3. The antenna according to claim 1, wherein a first end of the first length of the two conductor transmission line is connected to at least one of a transmitter or a receiver, and a second end of the first length of the two conductor transmission line is connected to a first end of the common-mode rejection filter, and a second end of the common mode rejection filter is connected to the dipole antenna element.

4. The antenna according to claim 3, wherein the first length of the two conductor transmission line is arranged to transfer currents in an arbitrary combination of a common mode and a differential mode.

5. The antenna according to claim 1, wherein the common mode rejection filter is designed to prevent a common-mode current from entering the dipole antenna element, which the common mode rejection filter lets a differential-mode current pass through in order to excite the dipole antenna element.

6. The antenna according to claim 1, wherein the common mode rejection filter is designed as two intertwined coils.

7. The antenna according to claim 6, wherein each coil is connected to one dipole arm, and to one first length of the transmission line conductor.

8. The antenna according to claim 1, further comprising:

a corrugated ground plane arranged to obtain a suitable impedance matching of a monopole/common mode excitation.

9. The antenna according to claim 1, further comprising:

at least one dielectric layer arranged above the dipole portion.

10. The antenna according to claim 9, wherein the at least one dielectric layer is arranged parallel to a plane wherein the dipole antenna element is arranged.

11. The antenna according to claim 1, wherein the first length of the two conductor transmission line and the second length of the two conductor transmission line above the common mode rejection filter at a same time constitute active and structural elements of the antenna.

12. An antenna array, comprising:

multiple antenna elements having a common ground plane, each antenna element comprising

a dipole antenna element having central feeding points,

a common mode rejection filter,

a first length of a two-conductor transmission line, and

a common mode rejection filter arranged and connected between a far end of the first length of the two-conductor transmission line and the feeding points of the dipole antenna element,

wherein the first length of the two-conductor transmission line is arranged to extend from a ground plane to a first height where the first length of the two-conductor transmission line is connected to the common mode rejection filter, and a second length of transmission line arranged to make a connection between the filter and the dipole and wherein the first length of the two conductor transmission line and the second length of the two conductor transmission line above the common mode rejection filter at a same time constitute active and structural elements of the antenna.

13. The antenna array according to claim 12, wherein the ground plane is corrugated.

14. The antenna array according to claim 12, further comprising:

at least one dielectric layer arranged above the dipole antenna element of each antenna element.

15. The antenna array according to claim 14, wherein the at least one dielectric layer is arranged parallel to the plane wherein the dipole antenna elements are arranged.

16. A method for using an array antenna comprising a plurality of antenna elements having a common ground plane, each antenna element comprising a dipole antenna element having central feeding points, a common mode rejection filter, a first length of a two-conductor transmission line, and a common mode rejection filter arranged and connected between a far end of the first length of the two-conductor transmission line and the feeding points of the dipole antenna element, wherein the first length of the two-conductor transmission line is arranged to extend from a ground plane to a first height where the first length of the two-conductor transmission line is connected to the common mode rejection filter, the method comprising:

exciting the array antenna with a radar pulse signal in differential mode;

phase-shifting the pulse signal in differential mode between array antenna elements to achieve scanning;

receiving radar echoes signals;

processing radar echoes signals;

exciting the array antenna with a radar pulse signal in common mode;

phase-shifting the pulse signal in common mode between array antenna elements to achieve scanning;

receiving radar echoes signals; and

processing radar echoes signals.