Electronic anti-theft system with correlated transmit/receive antennas

• US 20060034243A1
• Filed: 08/10/2005
• Published: 02/16/2006
• Est. Priority Date: 08/10/2004
• Status: Active Grant

• Current Assignee: Continental Automotive GmbH (Continental AG)
• Original Assignee: Siemens AG
• Inventors: Hermann, Stefan
• Granted Patent: US 7,532,608 B2
• Time in Patent Office: Days
• US Class Current: 370/343
• CPC Class Codes: B60R 25/245 where the antenna reception area plays a role
• CPC Class Codes: G07C 2209/61 Signal comprising different frequencies, e.g. frequency hopping
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: H01Q 21/30 Combinations of separate antenna units operating in different wavebands and connected to a common feeder system

Abstract

An electronic anti-theft system and an operating method have transmit/receive antennas of different frequencies that are electrically correlated with one another. The data communication of access code signals takes place at least partially via shared signal paths. A frequency decoupling of the access code signals is also performed. The transmit/receive antennas are preferably also embodied as structurally integrated. In this way a substantial simplification of the system and simultaneously also a cost optimization can be achieved.

Claims

1. A method for operating an electronic anti-theft system, which comprises the steps of:

performing data communication by transmitting and/or receiving electromagnetic access code signals via at least two transmit/receive antennas, the data communication of the access code signals takes place in a first permitted frequency band and also in at least a second permitted frequency band being different from the first permitted frequency band;

correlating the transmission and/or reception of the access code signals for signaling purposes;

performing the data communication of the access code signals at least partially via shared signal paths in the transmit/receive antennas; and

performing a frequency decoupling of the access code signals.

2. The method according to claim 1, wherein the first permitted frequency band designates an LF frequency band and the second permitted frequency band designates an HF frequency band.

3. An electronic anti-theft system, comprising:

at least two transmit/receive antennas for transmitting and/or receiving electromagnetic access code signals for performing data communication, said at least two transmit/receive antennas include at least a first transmit/receive antenna for data communication in a first frequency band, and at least a second transmit/receive antenna for data communication in a second frequency band being different from the first frequency band, and an at least partially constructional integration of at least a part of said two transmit/receive antennas.

4. The anti-theft system according to claim 3, further comprising an electrical coupling circuit, said first transmit/receive antenna and said second transmit/receive antenna are connected to a shared signal path through said electrical coupling circuit.

5. The anti-theft system according to claim 4, wherein said electrical coupling circuit is a coupling network with a characteristic selected from the group consisting of a low-pass characteristic and a band-pass characteristic.

6. The anti-theft system according to claim 3, wherein said first and said second transmit/receive antenna are connected to each other for signaling purposes.

7. The anti-theft system according to claim 3, further comprising a common carrier element, said first transmit/receive antenna and said second transmit/receive antenna are integrated on said common carrier element.

8. The anti-theft system according to claim 3, wherein said first transmit/receive antenna is an LF antenna having a coil with a transformer laminated core or ferrite core, for transmitting and/or receiving LF frequencies.

9. The anti-theft system according to claim 3, wherein said second transmit/receive antenna is an HF antenna having a printed circuit board, for transmitting and/or receiving HF frequencies.

10. The anti-theft system according to claim 3, wherein said common carrier element is a printed circuit board.