An active bolster protects a passenger in an automotive vehicle during a crash event. The composition is used for whitening paper, in particular in the size press. The method preprocesses the phase difference to generate a comparison waveform. Another instrument is a template for straddling the dura. The microwaves from a radar unit in the radar level gauge are supplied to the dielectric layer in the antenna via the transmission line and transmitted out in a radial direction from a feed point in the dielectric layer that acts as a waveguide.