Wide frequency band planar antenna

• US 6,278,410 B1
• Filed: 11/29/1999
• Issued: 08/21/2001
• Est. Priority Date: 11/29/1999
• Status: Expired due to Term

• Current Assignee: Katholieke Universiteit Leuven KU Leuven R&D
• Original Assignee: Interuniversitair Micro-Electronica Centrum VZW (IMEC International), Katholieke Universiteit Leuven KU Leuven R&D
• Inventors: Soliman, Ezzeldin, Vandenbosch, Guy, Beyne, Eric, De Raedt, Walter
• Primary Examiner(s): PHAN, THO GIA
• Application Number:
  US09/450,214
• Time in Patent Office: 631 Days
• Field of Search: H01/Q 1.312, H01/Q 1.310, H01/Q.138, 343/767, 343/769, 343/770, 343/700.MS, 343/768, 343/771, 343/829, 343/830, 343/846
• US Class Current: 343/769
• CPC Class Codes: H01Q 1/38 formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 19/005 Patch antenna using one or more coplanar parasitic elements

Abstract

The present invention provides a planar antenna having a first, outer planar conductive element and a second planar conductive element located in a hole in the outer element. At least 75% of the boundary between the hole and the first outer planar conductive element is a continuous concave smooth curve. The second planar conductive element is substantially coplanar with and surrounded by the first outer planar conductive element. At least 75% of the outer boundary of the second planar conductive element is a continuously convex smooth curve.

Claims

1. A planar antenna comprising:

a first outer planar conductive element defining an inner hole, at least 75% of the boundary between the hole and the first outer planar conductive element being a continuous concave smooth curve; and

a second planar conductive element substantially coplanar with and surrounded by the first outer planar conductive element, the second planar conductive element being located in the hole, at least 75% of the outer boundary of the second planar conductive element being a continuously convex smooth curve,

wherein a center of gravity of the hole of the first outer planar conductive element is offset from a center of gravity of the second planar conductive element to form a slot.

2. The antenna according to claim 1, wherein the smooth curve is a circle, an ellipse, an oval, or an egg-shape.

3. The antenna according to claim 1, wherein the slot is defined by the space between the offset second and first conductive elements.

4. The antenna according to claim 3, wherein the slot has a dimension perpendicular to the offset direction of at least 0.4 times the wavelength of a frequency at which the antenna is to operate.

5. The antenna according to claim 1, wherein the first and second conductive elements are mounted on a dielectric material.

6. The antenna according to claim 1, further comprising a conductive backing plate to eliminate radiation to and from the antenna in one direction.

7. The antenna according to claim 1, wherein a distance in the offset direction between an inner boundary of the first planar conductive element and an outer boundary thereof is 0.4 λ

₀ where λ

₀, is the free space wavelength at the operating frequency of the antenna.

8. The antenna according to claim 1, wherein the antenna has two resonance frequencies.

9. The antenna according to claim 8, wherein the resonance frequencies are in the GHz region.

10. A planar antenna comprising:

a first outer planar conductive element defining an inner hole, at least 75% of the boundary between the hole and the first outer planar conductive element being a continuous concave smooth curve; and

a second planar conductive element substantially coplanar with and surrounded by the first outer planar conductive element, the second planar conductive element being located in the hole, at least 75% of the outer boundary of the second planar conductive element being a continuously convex smooth curve;

wherein the second conductive element is connected to a coplanar waveguide.

11. The antenna according to claim 10, wherein the smooth curve is a circle, an ellipse, an oval, or an egg-shape.

12. The antenna according to claim 10, wherein the first and second conductive elements are mounted on a dielectric material.

13. The antenna according to claim 10, further comprising a conductive backing plate to eliminate radiation to and from the antenna in one direction.

14. The antenna according to claim 10, wherein the antenna has two resonance frequencies.

15. The antenna according to claim 14, wherein the resonance frequencies are in the GHz region.

16. The antenna according to claim 10, wherein a center of gravity of the hole of the first outer planar conductive element is offset from a center of gravity of the second planar conductive element to form a slot.

17. The antenna according to claim 16, wherein the slot is defined by the space between the offset second and first conductive elements.

18. The antenna according to claim 16, wherein a distance in the offset direction between an inner boundary of the first planar conductive element and an outer boundary thereof is 0.4 λ

₀, where λ

₀ is the free space wavelength at the operating frequency of the antenna.