Multi-phase transmitter with single receive antenna for transponder interrogator

• US 5,923,300 A
• Filed: 04/03/1997
• Issued: 07/13/1999
• Est. Priority Date: 04/03/1997
• Status: Expired due to Term

• Current Assignee: Destron Fearing Corporation (Merck & Co., Inc.)
• Original Assignee: Destron Fearing Corporation (Merck & Co., Inc.)
• Inventors: Mejia, E. Zeke
• Primary Examiner(s): Kim, Robert
• Assistant Examiner(s): Lauchman, Layla G.
• Application Number:
  US08/832,213
• Time in Patent Office: 831 Days
• Field of Search: 340/825.54, 343/742, 343/867, 343/895, 343/720, 343/866, 324/338, 324/332-337
• US Class Current: 343/788
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 7/06 with core of ferromagnetic material H01Q7/02 takes precedence

Abstract

An antenna includes a transmitter including a first transmit coil wound in a first direction. A second transmit coil is electrically coupled to the first transmitter and wound in a second direction opposite to the first direction.

Claims

1. An antenna, comprising:

a transmitter, said transmitter including a first transmit coil wound in a first direction, a second transmit coil, electrically coupled to said first coil, and wound in a second direction opposite to the first direction, and a receive coil disposed between said first transmit coil and said second transmit coil.

3. The antenna of claim 1, wherein said receive coil is disposed at a null point between said first transmit coil and said second transmit coil.

4. The antenna of claim 1, wherein said first coil and said second coil are coupled in series.

5. The antenna of claim 1, wherein said first coil and said second coil are coupled in parallel.

9. The antenna of claim 1, wherein said transmitter is sized and arranged to be disposed within a transponder interrogator.

2. An antenna, comprising:

a core, said core having a first end and second end;

a transmitter, said transmitter including a first transmit coil disposed at said first end of said core and wound in a first direction, a second transmit coil, disposed at said opposite end of said core, electrically coupled to said first coil, and wound in a second direction opposite to the first direction, and a receive coil disposed about said core between said first coil and second coil.

6. The antenna of claim 2, wherein said receive coil is disposed at a null point between said first transmit coil and said second transmit coil.

7. The antenna of claim 2, wherein said first coil and said second coil are coupled in series.

8. The antenna of claim 2, wherein said first coil and said second coil are coupled in parallel.

10. The antenna of claim 2, wherein said transmitter is sized and arranged to be disposed within a transponder interrogator.