PRINTED QUASI-TAPERED TAPE HELICAL ARRAY ANTENNA

• US 20120188142A1
• Filed: 09/22/2009
• Published: 07/26/2012
• Est. Priority Date: 08/06/2009
• Status: Active Grant

• Current Assignee: Indian Space Research Organisation (ISRO)
• Original Assignee: Indian Space Research Organisation (ISRO)
• Inventors: Shashi, Bhushan Sharma, Rajeev, Jyoti, Harjivan, Sanandiya, Sagi, Sravan Kumar, Yogesh, Harshadrai Trivedi, Bhargav, Nalinkant Pandya
• Granted Patent: US 9,444,148 B2
• Time in Patent Office: Days
• US Class Current: 343/860
• CPC Class Codes: H01Q 1/523 between antennas of an array
• CPC Class Codes: H01Q 11/083 Tapered helical aerials, e.g. conical spiral aerials
• CPC Class Codes: H01Q 21/067 using endfire radiating aerial units transverse to the plane of the array

Abstract

A printed quasi-tapered tape helical element and printed helical array antenna arc disclosed. The helical element comprises a thin helix conductor having a uniform section associated with a tapered section. The helix conductor can be printed on a thin dielectric sheet and bonded to a hollow composite dielectric support. A solid copper conductor is configured to provide electrical connection between a feeding point of the helix conductor and a microstrip line of a microstrip feed network. The uniform and tapered helix turns are respectively wrapped around the uniform and tapered sections, which enables impedance matching, axial mode excitation, gain and radiation patterns, and damping out of standing waves generated in current distribution over the helix conductor. Conductive composite cups surrounding each helical element reduces mutual coupling in array environment. Thus, the helical element and the array antenna achieve low on-axis and off-axis axial ratio performance over the wideband for global coverage.

Claims

1. A quasi-tapered tape helical element, comprising:

a thin helix conductor having a uniform section associated with a tapered section, wherein said helix conductor is printed on a thin dielectric sheet and bonded to a hollow composite dielectric support; and

a copper conductor for providing an electrical connection between a feeding point of said helix conductor and a microstrip line of a microstrip feed network, wherein uniform and tapered helix turns are respectively wrapped around said uniform and tapered sections and thereby for enabling impedance matching, axial mode excitation, gain and radiation patterns, and damping out of standing waves generated in current distribution over said helix conductor.

2. The helical element according to claim 1, further comprising:

a conductive composite ground plane, wherein said dielectric support is fastened and bonded to said conductive composite ground plane;

a feed network printed circuit board (PCB) in connection with said microstrip feed network and said conductive composite ground plane, said feed network printed circuit board (PCB) having a copper clad groundside; and

a dielectric composite honeycomb secured to said conductive composite ground plane, said dielectric composite honeycomb is sandwiched between said feed network PCB and said dielectric support.

3. The helical element according to claim 2, wherein the copper clad groundside of said feed network PCB is bonded to said conductive composite ground plane.

4. The helical element according to claim 1, wherein an adhesive bonds said helix conductor over the outer surface of said hollow composite dielectric support.

5. The helical element according to claim 1, wherein said tapered helix turns terminate said uniform helix turns.

6. The helical element according to claim 1, wherein said copper conductor acts as an impedance matching element.

7. The helical element according to claim 1, wherein the overall length of said helix element is less than one wavelength at lowest operating frequency.

8. The helical element according to claim 1, wherein said microstrip feed network is placed on a microwave substrate with a low coefficient of thermal expansion.

9. The helical element according to claim 1, wherein said microstrip feed network electromagnetically feeds said helix element for amplitude and phase distribution and impedance matching of said helix element.

10. A quasi-tapered tape helical array antenna, comprising:

one or more quasi-tapered tape helical elements as claimed in claim 1, arranged in array with inter-element spacing;

a plurality of quarter wave section transformers disposed within a corporate feed network for power division and transformation of impedance of said one or more helical elements to input impedance; and

a plurality of conductive cups surrounding said one or more helical elements in a conductive composite ground plane, wherein said conductive cups provide electromagnetic mutual coupling between said one or more helical elements.

11. The antenna according to claim 10, wherein the impedance of said one or more helical elements is configured to transform to 50 ohms input impedance within said corporate feed network.

12. The antenna according to claim 10, further comprising:

a conductive composite ground plane, wherein said one or more helical elements are fastened and bonded to said conductive composite ground plane;

a feed network printed circuit board (PCB) in connection with said corporate feed network and said conductive composite ground plane, said feed network printed circuit board (PCB) having a copper clad groundside; and

a dielectric composite honeycomb secured to said conductive composite ground plane, wherein said dielectric composite honeycomb is sandwiched between said feed network PCB and said one or more helical elements.

13. The antenna according to claim 12, wherein the copper clad groundside of said feed network PCB is bonded to said conductive composite ground plane.

14. The antenna according to claim 10, wherein the overall length of said one or more helical elements is less than one wavelength at lowest operating frequency.

15. The antenna according to claim 10, wherein said corporate feed network is placed on a microwave substrate with a low coefficient of thermal expansion.

16. The antenna according to claim 10, wherein said corporate feed network electromagnetically feeds said one or more helical elements for amplitude and phase distribution and impedance matching of said helix element.