| 摘要 |
Wire antennas (14, 22) define a target region (18), primarily between them. A generator (16) generates an electric field in the target region (18). A sensor arrangement (20) senses the electric field. Control means (25) is operable to analyze the field strength sensed by the sensor arrangement (20), for changes indicative of a change in conditions in the target region, such as the presence of a body (30). |
