An antenna includes a coil that is formed such that one end of the coil is short circuited or open to a ground and a current standing wave is generated when a high frequency signal is applied to another end of the coil. Each strip includes at least one web extending substantially mostly sideways on one side of the profiles. A memory in the processing system may include an ordinary memory area that can be accessed from the normal ring 0 operating mode, as well as an isolated memory area that can be accessed from the isolated execution mode but not from the normal ring 0 operating mode. The illumination system may be used in a projection system, with the light from the illumination system incident on an image-forming device placed at the target area. After attenuation of the AC power signal, the remaining signal is differentiated, rectified and smoothed to provide a DC signal representative of the pollution which can be viewed on an ordinary meter.