| 摘要 |
The present invention relates to a vehicle transponder (1) comprising an antenna (2) and a power directing means (3, 17, 18), the power directing means (3, 17, 18) having a first port (4, 4', 4"), a second port (5, 5', 5") and a third port (6, 6', 6"). The power directing means (3, 17, 18) is arranged to direct power from the first port (4, 4', 4") to the second port (5, 5', 5") and/or the third port (6, 6', 6"). The transponder further comprises a modulator (7), which comprises a first port (12), a second port (13) and a third port (14), where the second port (5, 5', 5") of the power directing means (3, 17, 18) is connected to the first port (12) of the modulator (7). In a first mode of operation, a received signal at the antenna (2) is directed to the modulator (7) via the power directing means (3, 17, 18), the modulator (7) being arranged to modulate the received signal by means of phase shifting. The second port (13) of the modulator (7) is connected to an active amplifying means (8) that is arranged to amplify and reflect the modulated signal to be transmitted via the antenna (2). |
