Abstract: The invention relates to a method for measurement of the radar target cross section of an object with both moving and fixed parts, which method comprises a first measurement with high frequency resolution, from which information can be extracted on modulations in the signal received that derive from moving parts of the object and fixed parts of the object respectively. The invention is characterized in that the method comprises a second measurement with high range resolution, and filtering of the measuring result obtained from the second measurement, which filtering is performed around a certain frequency that is obtained by means of the measuring result from the first measurement. The first measurement is preferably given a high frequency resolution in that it is performed with a narrow-band waveform, and the second measurement is suitably given a high range resolution in that it is performed with a broadband waveform.

Abstract: The invention relates to a method for measurement of the radar target cross section of an object with both moving and fixed parts, which method comprises a first measurement with high frequency resolution, from which information can be extracted on modulations in the signal received that derive from moving parts of the object and fixed parts of the object respectively. The invention is characterized in that the method comprises a second measurement with high range resolution, and filtering of the measuring result obtained from the second measurement, which filtering is performed around a certain frequency that is obtained by means of the measuring result from the first measurement.

Abstract: A frequency-selective surface designed to transmit (allow to pass through) electromagnetic radiation around one or more predetermined transmission frequencies. The frequency-selective surface comprises at least two layers, whereby the outer layer is made up of at least one electromagnetic reflecting layer with a periodic pattern of conductive elements. The periodic pattern of conductive elements is made to have a reflection resonance frequency for electromagnetic radiation which is of the order of three times higher than the desired transmission frequency. The inner layer is placed at a suitable predetermined distance from the outer layer. The inner layer is made up of at least one electromagnetic transmitting layer having a periodic pattern of aperture elements. The periodic pattern of aperture elements is made in order to have a transmission resonance frequency for electromagnetic radiation which is substantially the same as the desired transmission frequency.