Direction Finding Antenna Systems and Methods for Use Thereof

• US 20090315759A1
• Filed: 06/23/2008
• Published: 12/24/2009
• Est. Priority Date: 06/23/2008
• Status: Active Grant

• Current Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Original Assignee: Hong Kong Applied Science And Technology Research Institute Co., Ltd.
• Inventors: Rowell, Corbett R., Mak, Chi-Lun, Mak, Angus C. K.
• Granted Patent: US 7,924,225 B2
• Time in Patent Office: Days
• US Class Current: 342/147
• CPC Class Codes: G01S 3/043 Receivers
• CPC Class Codes: G01S 3/046 Displays or indicators
• CPC Class Codes: G01S 3/18 derived directly from separate directional antennas
• CPC Class Codes: G01S 3/40 adjusting orientation of a single directivity characteristic to produce maximum or minimum signal, e.g. rotatable loop antenna or equivalent goniometer system
• 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 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

An antenna system comprising a first antenna element, a second antenna element, and a parasitic element, wherein the parasitic element is arranged with regard to the first antenna element and the second antenna element such that a greatest difference in gain between respective antenna patterns of the first and second antenna elements occurs at a null of the pattern of the first antenna element.

Claims

1. An antenna system comprising:

a first antenna element;

a second antenna element; and

a parasitic element, wherein the parasitic element is arranged with regard to the first antenna element and said second antenna element such that a greatest difference in gain between respective antenna patterns of said first and second antenna elements occurs at a null of the pattern of the first antenna element.

2. The antenna system of claim 1 wherein the antenna pattern of said first antenna element comprises a cardioid.

3. The antenna system of claim 1 wherein the antenna pattern of said first antenna element comprises a single null.

4. The antenna system of claim 1 wherein the antenna pattern of said second antenna element is substantially omni directional.

5. The antenna system of claim 4 wherein the antenna pattern of said second antenna element has an overall difference in gain across all azimuth angles of less than 5 dB.

6. The antenna system of claim 1 wherein said first and second antenna elements are selected from the list consisting of:

horn elements;

helix elements;

monopole elements;

patch elements; and

PIFA elements.

7. The antenna system of claim 1 wherein one or both of said first and second elements comprises components selected from the list consisting of:

a slot;

a notch; and

an additional strip.

8. The antenna system of claim 1 further comprising at least one additional parasitic component.

9. The antenna system of claim 1 further comprising:

circuitry receiving signals using said respective antenna patterns, comparing signal strengths of the respective patterns, and providing an output indicating an amount of difference in said signal strengths.

10. The antenna system of claim 9 further comprising:

a user interface in communication with said circuitry receiving signals and providing an indication of direction.

11. A direction-finding antenna system comprising:

a first antenna element;

a second antenna element;

a parasitic component, wherein said parasitic component and said first and second antenna elements are configured such that said first antenna element has a pattern with a single null, and said second antenna element has a pattern that is substantially omni directional across all azimuths; and

circuitry receiving signals from each of said antenna patterns, comparing signal strengths thereof, and providing an indication of direction of a signal transmitter based at least in part on the comparing.

12. The direction-finding antenna system of claim 11 further comprising:

a user interface in communication with said circuitry receiving signals and operable to provide said indication of direction.

13. The direction-finding antenna system of claim 11, wherein said direction-finding antenna system is included in a handheld device.

14. The direction-finding antenna system of claim 11 wherein said pattern of said first antenna element includes a single null.

15. The direction-finding antenna system of claim 11 wherein said pattern of said second antenna element includes a single null that has more gain than a null of said pattern of said first antenna element.

16. The direction-finding antenna system of claim 11 further comprising:

a switch in communication with said first and second antenna elements and with said circuitry receiving signals, said switch alternatingly providing signals from said first and second antenna elements to said circuitry receiving signals.

17. A method for providing an indication of direction of a transmitter using an antenna system that includes a first and a second antenna element and a parasitic element, the method comprising:

receiving a signal from the transmitter using a pattern of the first antenna element;

receiving the signal from the transmitter using a pattern of the second antenna element, wherein a greatest difference in gain between the patterns of the first and second antenna elements occurs at an azimuth associated with a null of the pattern of the first antenna element;

ascertaining a difference in received signal strengths of the first and second antennas; and

outputting an indication of direction based at least in part upon said difference in received signal strengths.

18. The method of claim 17 wherein said greatest difference in gain is a known value, and said ascertained difference is compared to said known value.

19. The system of claim 18 wherein an ascertained value substantially corresponding to said known value indicates an azimuthal direction of said transmitter.

20. The method of claim 17 wherein receiving the signal from the transmitter using the pattern of the second antenna element comprises:

switching an input of an RF circuit to be electrically coupled to said second antenna element.

21. The method of claim 17 wherein receiving the signal from the transmitter using the pattern of the first antenna element comprises:

switching an input of an RF circuit to be electrically coupled to said first antenna element.

22. The method of claim 18 further comprising:

providing said indication of direction on a user interface.