Microwave transponder

• US 20080159071A1
• Filed: 12/16/2005
• Published: 07/03/2008
• Est. Priority Date: 12/21/2004
• Status: Abandoned Application

• Current Assignee: Kapsch TrafficCom AB (Datax Handelsgmbh)
• Original Assignee: Kapsch TrafficCom AB (Datax Handelsgmbh)
• Inventors: Johansson, Hans
• Application Number:
  US11/792,763
• Publication Number:
  US 20080159071A1
• Time in Patent Office: Days
• US Class Current: 367/2
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
• CPC Class Codes: G06K 19/07786 the antenna being of the HF type, such as a dipole

Abstract

The invention relates to a radio transponder (200) for reception and retransmission of electromagnetic energy, particularly in the microwave range. The transponder comprises a connection (210) to an antenna, a control circuit for modulation (260), a detector (250), a delay element (240) and a first semiconductor switch (220). The transponder comprises, in addition, a second semiconductor switch (230), and the control circuit for modulation (260) is arranged to be able to control the semiconductor switches (220, 230) independently in such a way that a signal that comes in via the antenna connection (210) can be caused to be reflected on either side of the delay element (240) or to pass through this to the detector (250). At least one of the semiconductor switches (220, 230) is suitably a diode or a transistor.

Claims

1. Radio transponder for reception and retransmission of electromagnetic energy, which transponder comprises:

an antenna connection,

a control circuit for modulation,

a detector,

a delay element,

a first semiconductor switch,

a second semiconductor switch, and

wherein the control circuit for modulation is arranged to control the first and second semiconductor switches independently in such a way that a signal that comes in via the antenna connection can be caused to be reflected on either side of the delay element or to pass through this to the detector.

2. Radio transponder according to claim 1, in which at least one of the first and second semiconductor switches comprises a diode.

3. Radio transponder according to claim 1, in which at least one of the first and second semiconductor switches comprises a transistor.

4. Radio transponder of claim 1, further comprising at least a first low-pass filter arranged between the control circuit for modulation and one of the first and second semiconductor switches.

5. Radio transponder according to claim 1, wherein the delay element and the detector are connected in series with the connector for an antenna.

6. Radio transponder according to claim 1, wherein the delay element provides a delay of a quarter of a wavelength.

7. Method for receiving radio signals primarily in the microwave range in a radio transponder, comprising:

utilizing a connection to a single antenna, and

controlling a control circuit to bring about one of the following three options for a received signal;

direct retransmission,

modulated retransmission,

detection in a detector.

8. Method according to claim 7, according to which the control circuit utilizes a first and a second semiconductor switch.

9. Method according to claim 7, according to which the modulation is carried out by means of a delay element through which the signal can be taken by means of one semiconductor switch.

10. Method according to claim 7, wherein the delay that is obtained by means of the delay element is a quarter of a wavelength.

11. A method for receiving microwave electromagnetic signals, comprising:

receiving a signal at a connection to a single antenna; and

controlling the path of the signal to either pass through a delay element or bypass the delay element through a first controllable switch and a second controllable switch, wherein controlling includes enabling one of direct retransmission, modulated retransmission, and detection in a detector.

12. The method of claim 11, wherein controlling the path includes placing both controllable switches in a non-conducting mode such that the signal travels through the delay element and detecting the signal in a detector at a non-antenna side of the delay element.

13. The method of claim 12, wherein controlling includes delaying the signal by of a quarter of a wavelength.

14. The method of claim 11, wherein controlling the path includes placing the first controllable switch in a conducting mode and placing the second switch in a non-conducting mode to reflect the signal before the delay element.

15. The method of claim 11, wherein controlling the path includes placing the first controllable switch in a non-conducting mode and placing the second switch in a conducting mode to reflect the signal after the delay element.

16. The method of claim 11, wherein controlling the path includes placing the first controllable switch in a conducting mode and placing the second switch in a conducting mode to reflect the signal before the delay element.