0420180-A1 is referenced by 8 patents and cites 6 patents.

A transponder (200) for a vehicle identification device in which a radio wave (F) including vehicle information returned from transponders (200) provided in vehicle is received by an interrogator (1) and the transponder (200) receives and detects a query radio wave (a) and generates a previously memorized coded signal train (e) in response to the detection output (b), then the coded signal train (e) varies an amount of a bias voltage (232) of the detection device (230), whereby a reflection coefficient of the detection device (230) is varied to modulate the reflection wave (F) of a query radio wave (a), then the modulated microwave (F) is transmitted back to the interrogator (1).

Title
Transponder for vehicle identification device.
Application Number
EP19900118461 19900926
Publication Number
0420180 (A1)
Application Date
September 26, 1990
Publication Date
April 3, 1991
Inventor
Sasaki Kunihiko
JP
Kodera Masao
JP
Utsu Jyunshi
JP
Assignee
Nippon Soken
JP
IPC
G06K 07/10
G01S 13/82
G07C 09/00
G06K 07/00
G01S 13/00
G07C 09/00
G06K 07/00
G01S 13/82
G01S 13/74
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