Multi-resonant antenna

• US 5,999,132 A
• Filed: 10/01/1997
• Issued: 12/07/1999
• Est. Priority Date: 10/02/1996
• Status: Expired due to Fees

• Current Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Johnston, Ronald Harvey, Kitchener, Dean
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US08/943,384
• Time in Patent Office: 797 Days
• Field of Search: 343/702, 343/790, 343/791, 343/792, 343/795, 343/700 MS, 343/729, 343/730
• US Class Current: 343/702
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system
• CPC Class Codes: H01Q 5/321 within a radiating element or between connected radiating elements
• CPC Class Codes: H01Q 5/48 Combinations of two or more dipole type antennas
• CPC Class Codes: H01Q 9/32 Vertical arrangement of element H01Q9/40 takes precedence
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength
• CPC Class Codes: H01Q 9/44 with a plurality of divergent straight elements, e.g. V-dipole, X-antenna; with a plurality of elements having mutually inclined substantially straight portions combinations of two or more active elements H01Q21/00; turnstile antennas H01Q21/26

Abstract

The present invention relates to antennas and in particular relates to a multi-resonant antenna. The present invention addresses the requirement for dual frequency antennas operable in two distinct frequency bands. In accordance with a first aspect of the invention, there is provided a multi-resonant antenna comprising first and second conductive elements which antenna elements extend relative to a ground plane; wherein the elements of the antenna structure are adapted to couple between themselves to provide a variable phase velocity for surface currents of the radio signals. A method of operation is also disclosed.

Claims

1. A multi-resonant planar antenna comprising first and second conductive elements disposed in a plane that are connected to a single RF feed adjacent a ground plane;

the elements of the antenna are of a length and spacing relative to each other such that electromagnetic radio signals carried thereby can couple between themselves to provide a variable phase velocity for surface currents of the radio signals.

2. A multi-resonant planar antenna comprising first and second coupled lines disposed in a plane and operable to transmit and receive radio signals, a single RF feed and a ground plane, the coupled lines are connected via a physical electrical conductor to the feed and the feed exchanges radio signals with the first line, which line extends from the ground plane, and;

the lines are coupled such that at a first frequency, the phase velocity of the surface currents across the coupled lines are increased and, at a second, higher frequency, the phase velocity of the surface currents across the coupled lines are decreased.

3. A multi-resonant antenna according to claim 2 wherein the coupled lines are transmission lines and are coupled at a distal end of the physical electrical conductor.

4. A multi-resonant antenna according to claim 2, wherein said second line is parallel with said first line.

5. A multi-resonant antenna according to claim 2, further comprising a third coupled line.

6. A multi-resonant antenna according to claim 2, further comprising a third coupled line, which third line is parallel with said first line.

7. A multi-resonant antenna comprising first, second and third coupled lines operable to transmit and receive radio signals, a single RF feed and a ground plane wherein the coupled lines are connected via a physical electrical conductor to the feed;

wherein the feed exchanges radio signals with the first line, which line extends outwards from the ground plane, and;

wherein the lines are coupled such that at a first frequency, the phase velocity of the surface currents across the coupled lines are increased and, at a second, higher frequency, the phase velocity of the surface currents across the coupled lines are decreased.

8. A multi-resonant antenna according to claim 7, further comprising a fourth coupled line, which fourth line is parallel with said first line.

9. A multi-resonant antenna according to claim 7, further comprising a fourth coupled line, which fourth line is connected to the first line proximate to the feed.

10. A multi-resonant antenna according to claim 7, further comprising a fifth coupled line, which fifth coupled line is connected via a physical electrical conductor connected to the feed.

11. A multi-resonant antenna according to claim 7, further comprising a fifth coupled line, which fifth line is parallel with said first line and is connected via a physical electrical conductor connected to the feed.

12. A multi-resonant antenna according to claim 7, further comprising a fifth coupled line, which fifth line is connected to the first line proximal the feed.

13. A multi-resonant planar antenna comprising adjacently placed conductive lines disposed in a plane, the lines being connected via a physical electrical conductor to a single RF feed, which lines have a frequency response such that, at a high frequency mode of operation, the phase velocity of surface currents is reduced and at a lower frequency mode of operation, the phase velocity of surface currents is increased.

14. A method of operating a multi-resonant antenna, said multi-resonant antenna comprising first and second coupled lines disposed in a plane and operable to transmit radio signals, a single RF feed and a ground plane, the first line extends from the ground plane and the coupled lines are connected via a physical electrical conductor to the single RF feed;

wherein, in a transmit mode, the method comprises the steps of providing radio signals, via the feed, to the first line, wherein the lines are coupled such that at a first frequency, the phase velocity of the surface currents across the coupled lines are increased and, at a second, higher frequency, the phase velocity of the surface currents across the coupled lines are decreased;

whereby the lines resonate and the signals are transmitted via the lines.

15. A multi-resonant antenna according to claim 14 wherein the coupled lines are transmission lines and are connected at a distal end of the physical electrical conductor.

16. A multi-resonant antenna according to claim 14, wherein said second line is parallel with said first line.

17. A multi-resonant antenna according to claim 14, further comprising a third coupled line.

18. A multi-resonant antenna according to claim 14, further comprising a third coupled line which third coupled line is connected via a physical electrical conductor connected to the feed line, which third coupled line is parallel with said first coupled line.

19. A method of operating a multi-resonant planar antenna, said multi-resonant planar antenna comprising first and second coupled lines disposed in a plane and operable to receive radio signals, a single RF feed and a ground plane, the first line extends from the ground plane, and the coupled lines are connected via a physical electrical conductor to the single RF feed;

wherein, in a receive mode, the method comprises the steps of receiving radio signals, via the coupled lines such that at a first frequency, the phase velocity of the surface currents across the coupled lines are increased and, at a second, higher frequency, the phase velocity of the surface currents across the coupled lines are decreased;

whereby the lines resonate and the coupled radio signals are output via the feed.

20. A multi-resonant antenna according to claim 19 wherein the coupled lines are transmission lines and are connected at a distal end of the physical electrical conductor.

21. A multi-resonant antenna according to claim 19, wherein said second line is parallel with said first line.

22. A multi-resonant antenna according to claim 19, further comprising a third connected line.

23. A multi-resonant antenna according to claim 19, further comprising a third coupled line which third line is connected via a physical electrical conductor connected to the feed, which third line is parallel with said first line.