Short-range magnetic communication system

Patent 5771438 Issued on June 23, 1998. Estimated Expiration Date:

March 26, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

3617890

3898565

Short range induction field communication system
Patent #: 4061972
Issued on: 12/06/1977
Inventor: Burgess

Inductive communication system
Patent #: 4117271
Issued on: 09/26/1978
Inventor: Teeter , et al.

Antenna circuit of the negative impedance type
Patent #: 4442434
Issued on: 04/10/1984
Inventor: Baekgaard

Electromagnetic induction coil antenna
Patent #: 4489330
Issued on: 12/18/1984
Inventor: Marutake , et al.

Time division adaptive retransmission technique for portable radio telephones
Patent #: 4513412
Issued on: 04/23/1985
Inventor: Cox

Dual-antenna transceiver
Patent #: 4542532
Issued on: 09/17/1985
Inventor: McQuilkin

Cordless communications system
Patent #: 4584707
Issued on: 04/22/1986
Inventor: Goldberg , et al.

Electronic proximity identification and recognition system with isolated two-way coupling
Patent #: 4600829
Issued on: 07/15/1986
Inventor: Walton

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Inventors

Assignee

Aura Communications, Inc.

Application

No. 824260 filed on 03/26/1997

US Classes:

455/41.1, Near field (i.e., inductive or capacitive coupling)455/11.1, Portable or mobile repeater455/101, Diversity455/133With output selecting

Examiners

Primary: Eisenzopf, Reinhard J.
Assistant: Nguyen, Lee

Attorney, Agent or Firm

Testa, Hurwitz & Thibeault, LLP

Foreign Patent References

2431227 FR. 07/13/1978
78/20886 FR. 07/13/1978
2431227 FR. 02/13/1980
3603098 A1 DE. 01/13/1987
3603098 DE 01/13/1987
36 03 098 A1 DE. 02/13/1988
9309032U DE. 11/13/1994
93 09 032 DE. 12/13/1994
36 03 098 A1 DE. 01/13/1997
1164281 GB. 09/13/1966
1164281 GB. 09/13/1969
2197160 GB. 09/13/1987
2197160 GB. 05/13/1988
2277422 GB. 10/13/1994
96/37052 WO. 11/13/1996

International Class

H04B 005/06

Abstract

A system and method communicate signals between a portable unit and a communications system. The portable device communicates with a base unit using inductive coupling. The base unit is further connected to a wider communication system such as a telephone network. Multiple, orthogonally arranged transducers are used in the base unit to provide a more complete magnetic field and to prevent mutual inductance nulls which are otherwise present in a magnetic field. The use of short-range inductive coupling minimizes the power requirements and limits interference with other sources. The inductive coupling may also be used to recharge a battery in the portable device.