Dielectric leaky-wave antenna

• US 6,489,930 B2
• Filed: 12/19/2000
• Issued: 12/03/2002
• Est. Priority Date: 02/29/2000
• Status: Expired due to Fees

• Current Assignee: Anritsu Corporation
• Original Assignee: Anritsu Corporation
• Inventors: Yamamoto, Aya, Teshirogi, Tasuku, Hidai, Takashi, Kawahara, Yuki
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US09/741,276
• Publication Number:
  US 20010017603A1
• Time in Patent Office: 714 Days
• Field of Search: H01/Q 1.300, 343/700.MS, 343/753, 343/754, 343/767, 343/770, 343/771, 343/772, 343/776, 343/785, 343/786, 333/238, 333/239
• US Class Current: 343/785
• CPC Class Codes: H01Q 13/28 comprising elements constituting electric discontinuities and spaced in direction of wave propagation, e.g. dielectric elements or conductive elements forming artificial dielectric
• CPC Class Codes: H01Q 21/0068 Dielectric waveguide fed arrays

Abstract

A dielectric slab is arranged on one surface of a ground plane to form a transmission guide for transmitting an electromagnetic wave along the surface from one end to the other end between the dielectric slab and the ground plane. A perturbation is loaded on the dielectric slab to leak the electromagnetic wave from the surface of the dielectric slab. A feed supplies an electromagnetic wave to one end of the transmission guide formed by the ground plane and dielectric slab. A dielectric layer is interposed between the ground plane and the dielectric slab, and has a lower permittivity than that of the dielectric slab.

Claims

1. A dielectric leaky-wave antenna comprising:

a ground plane;

a dielectric slab arranged on one surface of said ground plane to form a transmission guide for transmitting an electromagnetic wave along a surface from one end to the other end between said dielectric slab and said ground plane;

a plurality of perturbations arranged on said dielectric slab at regular intervals in a transmission direction of the electromagnetic wave for leaking the electromagnetic wave from said dielectric slab;

a feed for supplying the electromagnetic wave to one end of the transmission guide formed by said ground plane and said dielectric slab over a distance equal to an entire width of the transmission guide in a direction perpendicular to the transmission direction; and

a dielectric layer which is interposed between said ground plane and said dielectric slab and has a lower permittivity than a permittivity of said dielectric slab;

wherein said ground plane comprises a flat metallic plate having a predetermined outer shape, said dielectric slab has an outer shape corresponding to the outer shape of said ground plane, and said dielectric layer has an outer shape corresponding to the outer shape of said dielectric slab.

2. An antenna according to claim 1, wherein said dielectric layer includes a gas layer including air or a vacuum layer.

3. An antenna according to claim 1, wherein each of said perturbations is formed from a metallic strip or slot provided perpendicular to the transmission direction.

4. An antenna according to claim 1, wherein each of said perturbations is formed from a metallic strip or slot having an angle of 45°

with respect to the transmission direction.

5. An antenna according to claim 1, wherein said plurality of perturbations include a pair of metallic strips or pair of slots which form an angle of 90°

with each other, and which are loaded on said dielectric slab so as to form an angle of 45°

with respect to the transmission direction.

6. An antenna according to claim 1, wherein said plurality of perturbations include a pair of perturbations parallel-arranged at an interval of approximately ¼

of a wavelength of the electromagnetic wave in the transmission direction.

7. An antenna according to claim 6, wherein one of said pair of perturbations is formed on one surface of said dielectric slab, and the other is formed on an opposite surface of said dielectric slab.

8. An antenna according to claim 6, wherein said pair of perturbations are formed on an upper surface of said dielectric slab.

9. An antenna according to claim 1, wherein:

said feed is formed to radiate a cylindrical wave, and

a wave-front conversion section is arranged at a first end of said dielectric slab for converting the cylindrical wave radiated by said feed into a plane wave and guiding the plane wave to the transmission guide.

10. An antenna according to claim 9, wherein said wave-front conversion section is formed by extending said dielectric slab toward said feed.

11. An antenna according to claim 10, wherein a matching section for matching said feed and said wave-front conversion section and guiding the electromagnetic wave supplied by said feed to said wave-front conversion section is arranged at a distal end of said wave-front conversion section.

12. An antenna according to claim 11, wherein said matching section is tapered to decrease in thickness toward an electromagnetic wave input side.

13. An antenna according to claim 11, wherein said matching section is formed from a dielectric having a permittivity different from a permittivity of said dielectric slab.

14. An antenna according to claim 10, wherein:

said feed is formed to transmit an electromagnetic wave input at a first end of said feed to the first end of said dielectric slab along said ground plane and to radiate the electromagnetic wave from an aperture at a second end of said feed that is formed to surround an edge of the first end of said dielectric slab, and

a matching section, projecting toward said ground plane so as to decrease a gap between said feed and a surface of said wave-front conversion section stepwise or continuously toward said wave-front conversion section in order to match said feed and said wave-front conversion section, is arranged in the aperture at the second end of said feed.

15. An antenna according to claim 9, wherein:

said wave-front conversion section has a reflecting wall for converting the cylindrical wave into the plane wave and reflecting the plane wave, and is arranged to make one half of the reflecting wall face the first end of said dielectric slab, and

said feed is arranged on a side opposite to said dielectric slab via said ground plane while a radiation surface faces the other half of the reflecting wall of said wave-front conversion section so as to radiate an electromagnetic wave toward the other half.

16. An antenna according to claim 15, wherein a matching section for matching said wave-front conversion section and the transmission guide of said dielectric slab is arranged at the first end of said dielectric slab.

17. An antenna according to claim 16, wherein said matching section is tapered to decrease in thickness toward an electromagnetic wave input side.

18. An antenna according to claim 16, wherein said matching section is formed from a dielectric having a permittivity different from a permittivity of said dielectric slab.

19. An antenna according to claim 15, wherein:

said wave-front conversion section is formed to transmit an electromagnetic wave reflected by the reflecting wall to the first end of said dielectric slab along said ground plane and to radiate the electromagnetic wave from an aperture at a second end of said feed that is formed to surround an edge of the first end of said dielectric slab, and

a matching section, projecting toward said ground plane so as to decrease a gap between said feed and a surface of said dielectric slab stepwise or continuously toward said dielectric slab in order to match said wave-front conversion section and the transmission guide of said dielectric slab, is arranged in the aperture at the second end of said wave-front conversion section.

20. An antenna according to claim 9, wherein

said feed has a plurality of radiators having different radiation center positions, and

said wave-front conversion section converts a cylindrical wave radiated by each radiator into a plane wave whose wave front is inclined at an angle corresponding to the radiation center position of said each radiator, and supplies the plane wave to the transmission guide.

21. A dielectric leaky-wave antenna comprising:

a ground plane;

a dielectric slab arranged on one surface of said ground plane to form a transmission guide for transmitting an electromagnetic wave along a surface from one end to the other end between said dielectric slab and said ground plane;

a plurality of perturbations loaded across said dielectric slab with respect to a transmission direction of the electromagnetic wave for leaking the electromagnetic wave from said dielectric slab;

a feed for supplying the electromagnetic wave across an entire width of the transmission guide formed by said ground plane and said dielectric slab; and

a dielectric layer which is interposed between said ground plane and said dielectric slab and has a lower permittivity than a permittivity of said dielectric slab.