| 摘要 |
A device for information transmission, a so-called transponder, for receiving a first microwave signal, modulating and coding, and retransmitting a second microwave signal, comprising at least one antenna means made in microstrip technique is described. The device is characterized primarily in that the antenna means comprises an antenna layer (20), acting towards a ground plane (21), the antenna layer and the ground plane having essentially equal area, and in that the device further comprises a reflex means (23), arranged next to or at a distance of at most 1/6 of the air wave length of the first microwave signal from the edges of the antenna layer and the ground plane, so that an antenna lobe directional from the antenna means is obtained, comprised of directly transmitted microwave signal and reflected microwave signal. With this embodiment a device is obtained that is compact, effective, light and inexpensive and gives a well defined and directional antenna lobe for communication with a good range. |
