Antenna device

摘要

The document discloses an antenna device (5) for e.g. the receiving part of an electronic key system within a vehicle. The antenna device (5) includes an antenna element (10), a substrate (7) on which a wireless circuit (8), and electronic circuit (9) are aranged in positional isolation. A conductor (30) e.g. wire harness is connected to the substrate to connect the antenna device to another device. In order to stabilize the antenna properties against different layout situations of the wire harness (30) a stub (23) is formed in the substrate (7), The stub (23) has a pattern length that causes resonance at one fourth of a wavelength of the communication signal and serves as counterpoise for the antenna element (10). The positional isolation of wireless circuit (8) and electronic circuit (9) further stabilizes the antenna properties.