Ultra-wideband magnetic antenna

• US 6,400,329 B1
• Filed: 07/13/2000
• Issued: 06/04/2002
• Est. Priority Date: 09/09/1997
• Status: Expired due to Fees

• Current Assignee: Time Domain Corporation (Humatics Corporation)
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: Barnes, Mark Andrew
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): VANNUCCI, JAMES
• Application Number:
  US09/615,314
• Time in Patent Office: 691 Days
• Field of Search: 343/787, 343/767, 343/770, 343/769, 343/768
• US Class Current: 343/787
• CPC Class Codes: H01Q 13/10 Resonant slot antennas
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 9/005 for radiating non-sinusoidal waves
• CPC Class Codes: H01Q 9/28 Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00

Abstract

An ultra-wideband magnetic antenna includes a planar conductor having a first and a second slot about an axis. The slots are substantially leaf-shaped having a varying width along the axis. The slots are interconnected along the axis. A cross polarized antenna system is comprised of an ultra-wideband magnetic antenna and an ultra-wideband dipole antenna. The magnetic antenna and the dipole antenna are positioned substantially close to each other and they create a cross polarized field pattern. The present invention provides isolation between a transmitter and a receiver in an ultra-wideband system. Additionally, the present invention allows isolation among radiating elements in an array antenna system.

Claims

1. A method of isolating a plurality of ultra-wideband (UWB) antennas, comprising:

(a) providing at least a first antenna of said plurality of UWB antennas having a null in a radiated field in a plane coincident with said first antenna; and

(b) positioning at least a second antenna of said plurality of UWB antennas within said plane, wherein said positioning isolates said first antenna from said second antenna to prevent electromagnetic loading.

2. A method of claim 1, wherein said step of providing at least a first UWB antenna, further comprises:

(i) providing an ultra-wideband (UWB) magnetic antenna, wherein said UWB magnetic antenna radiates a first E field and a first H field, and wherein said UWB magnetic antenna comprises

(1) a planar conductor sheet having a first and a second slot placed about an axis and said slots being interconnected about said axis, said first and second slots having a width, w, along said axis that varies substantially continuously from a central point to a distal end of each slot, and

(2) a pair of terminals located about an axis such that said UWB magnetic antenna transmits and receives electromagnetic waves when energized at said terminals and generates a signal across said terminals when excited by electromagnetic waves.

3. The method of claim 2, wherein said step of positioning at least a second UWB antenna comprises:

(ii) providing an ultra-wideband (UWB) electric antenna, wherein said UWB electric antenna radiates a second E field and a second H field.

4. The method of claim 3, wherein said step of providing said UWB electric antenna further comprises:

(c) positioning said UWB magnetic antenna substantially close to said UWB electric antenna; and

(d) creating a cross polarized field pattern, wherein said first E field and said first H field are substantially orthogonal to said second E field and said second H field.

5. The method of claim 4, wherein said method further comprises:

(e) positioning said UWB electric antenna substantially parallel to said UWB magnetic antenna.

6. The method of claim 5, wherein said method further comprises:

(f) positioning said UWB electric antenna and said UWB magnetic antenna at a distance of 0.44 λ

apart, whereby λ

is a signal'"'"'s wavelength either received or transmitted by the cross polarized antenna system.

7. The method of claim 4, wherein said method further comprises:

(e) positioning said UWB electric antenna in the same plane with said UWB magnetic antenna.

8. The method of claim 4, wherein said method further comprises:

(e) positioning said UWB electric antenna side by side with said UWB magnetic antenna; and

(f) placing said antennas on a back reflector, thereby producing an additional signal gain within the cross polarized antenna system.

9. The method of claim 4, wherein said method further comprises:

(e) providing said UWB electric antenna to receive signals; and

(f) providing said UWB magnetic antenna to transmit signals.

10. The method of claim 4, wherein said method further comprises:

(e) providing said UWB electric antenna to transmit signals; and

(f) providing said UWB magnetic antenna to receive signals.

11. The method of claim 4, wherein said method further comprises:

(e) providing said UWB magnetic antenna comprising said first and said second slots having said width, w, defined as $w=\frac{1}{4<br><br>\mathrm{Cos}<br><br>\left[l<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\pi <br><br>}\right]<br><br>\left(1-\mathrm{Cos}<br><br>\left[l<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\pi <br><br>}\right]\right)}$

and is a perpendicular distance between a point on an edge of each said slot and said axis, and wherein l is a length of each said slot.

12. The method of claim 4, wherein said method further comprises:

(e) positioning said first slot and said second slot of said UWB magnetic antenna symmetrically about said axis.

13. The method of claim 4, wherein said method further comprises:

(e) positioning said first slot and said second slot of said UWB magnetic antenna asymmetrically about said axis.

14. The method of claim 4, wherein said method further comprises:

(e) providing said planar conductor sheet having a length of at least λ

_c/2 and width of at least λ

_c/4, where λ

_c is a wavelength of the center frequency of a selected bandwidth.

15. The method of claim 4, wherein said method further comprises:

(e) providing said planar conductor sheet having a length of approximately 5.25 inches and a width of approximately 2.5 inches.

16. The method of claim 4, wherein said method further comprises:

(e) providing said first slot and said second slot which are substantially leaf-shaped.