Antenna which is made from a photonic band gap (PBG) material and which comprises a lateral wall surrounding an axis

• US 7,388,557 B2
• Filed: 04/29/2005
• Issued: 06/17/2008
• Est. Priority Date: 05/19/2004
• Status: Expired due to Fees

• Current Assignee: Centre National De La Recherche Scientifique
• Original Assignee: Centre National De La Recherche Scientifique
• Inventors: Pointereau, Elisa, Freytag, Laure, Jecko, Bernard
• Primary Examiner(s): Owens; Douglas W.
• Assistant Examiner(s): Tran; Chuc
• Application Number:
  US11/579,317
• Publication Number:
  US 20070236405A1
• Time in Patent Office: 1,145 Days
• Field of Search: 343754-756, 343/709, 343/702, 343/779, 343/872, 343/786, 343/909
• US Class Current: 343/872
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use
• CPC Class Codes: H01Q 1/245 with means for shaping the antenna pattern, e.g. in order to protect user against rf exposure
• CPC Class Codes: H01Q 1/52 Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure absorbing means H01Q17/00
• CPC Class Codes: H01Q 15/006 Selective devices having photonic band gap materials or materials of which the material properties are frequency dependent, e.g. perforated substrates, high-impedance surfaces
• CPC Class Codes: H01Q 19/06 using refracting or diffracting devices, e.g. lens radome H01Q1/42
• CPC Class Codes: H04B 1/3838 Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use
• CPC Class Codes: H04M 1/0214 Foldable telephones, i.e. with body parts pivoting to an open position around an axis parallel to the plane they define in closed position combined with translation movement H04M1/0235
• CPC Class Codes: H05K 1/0213 Electrical arrangements not otherwise provided for
• CPC Class Codes: H05K 1/148 Arrangements of two or more hingeably connected rigid printed circuit boards, i.e. connected by flexible means

Abstract

A antenna made from a photonic band-gap (PBG) material, includes: a lateral wall (4) which is made from a PBG material and which completely surrounds a central axis (6), the wall being disposed at a distance from the central axis such as to form a central resonant cavity; and at least one radiating element (34) which is placed inside the cavity. Each radiating element is positioned inside the cavity in order to excite an electromagnetic field parallel to the central axis and the radiating element(s) can excite the modes of the central cavity having a radial resonance more strongly than the other modes of the cavity.

Claims

1. An antenna made of photonic band gap material, comprising:

a side wall of PBG material completely surrounding a central axis and spaced apart from said central axis to leave a resonant central cavity suitable for creating at least one narrow frequency passband within a broad frequency stop band of the PBG material; and

at least one radiating element placed inside the cavity, suitable for exciting an electromagnetic field for radiating or receiving electromagnetic radiation at a given operating frequency situated within the narrow frequency passband;

wherein;

the radiating element is positioned inside the cavity so as to excite an electromagnetic field parallel to the central axis; and

said at least one radiating element is suitable for exciting the modes of the central cavity that present radial resonance more strongly than the other modes of the central cavity.

2. An antenna according to claim 1, wherein the radiating element is suitable for exciting only those modes of the central cavity that present radial resonance.

3. An antenna according to claim 1, wherein at least one of the radiating elements forms an individual electric dipole parallel to or coinciding with the central axis.

4. An antenna according to claim 3, wherein at least one of the radiating elements forms an individual magnetic dipole parallel to or coinciding with the central axis, and wherein the radiating elements are adapted to work at the same operating frequency, and wherein the radiating element forming an individual electric dipole is excited in phase quadrature relative to the radiating element forming an individual magnetic dipole so as to create circular polarization.

5. An antenna according to claim 1, wherein at least one of the radiating elements forms an individual magnetic dipole parallel to or coinciding with the central axis.

6. An antenna according to claim 1, wherein the antenna includes at least one probe placed inside the cavity, the probe having one or more of said radiating elements.

7. An antenna according to claim 6, including at least one conductor plane perpendicular to the central axis, and wherein the probe is supported by the or one of the conductor planes.

8. An antenna according to claim 7, including at least two probes disposed relative to one another in such a manner that one of the probes is the electric image of the other symmetrically about the conductor plane.

9. An antenna according to claim 6, including a central core of conductive material aligned on the central axis, and wherein the probe is supported by said central core.

10. An antenna according to claim 9, including an electrical conductor feeding the probe and passing inside the central core.

11. An antenna according to claim 9, including a plurality of radiating elements uniformly distributed around the periphery of the central core.

12. An antenna according to claim 6, including a support for holding the probe in place in the cavity, said support being made of a material of relative permittivity that is equal to the relative permittivity of the material filling the cavity to within ±

3.

13. An antenna according to claim 6, wherein the probe is selected from a set comprising an electric dipole and a wire-and-plate probe.

14. An antenna according to claim 1, including a plurality of radiating elements disposed at different heights along the central axis.

15. An antenna according to claim 1, including a plurality of radiating elements disposed at the same height along the central axis.

16. An antenna according to claim 1, wherein the central cavity presents two open ends through which the central axis passes, and wherein the antenna includes at least one closure cap for closing one of the open ends, the closure cap being made of a dielectric material of relative permittivity lying in the range 1 to 3.

17. An antenna according to claim 1, wherein the side wall of PBG material comprises a structure of metal PBG material.

18. An antenna according to claim 1, wherein the cavity is in the form of a barrel, the axis of symmetry of the barrel coinciding with the central axis.

19. An antenna according to claim 1, wherein the cavity is a circular cylinder of axis of symmetry that coincides with the central axis.

20. An antenna according to claim 1, wherein the central cavity presents two open ends through which the central axis passes, and wherein the central core comprises two flared portions connected together by a narrower portion, each of the flared portions partially closing a respective one of the open ends.