Abstract: A waveguide antenna (1) has an upper (2) and air (3) cavity waveguide, these waveguides being separated by a partition wall (4). Transversely extending slots (7) are disposed along the center line of the upper waveguide (2) with a mutual spacing of one wavelength-distance (.lambda..sub.g). Two slots (6) which extend in the direction of the longitudinal axis of the waveguide are disposed between the transversal slots (7). The partition wall (4) is provided with longitudinally extending slots (8) immediately beneath the longitudinally extending slots (6), and field-shifting posts (9) are placed in the lower waveguide (3) adjacent the latter slots (8) in a zig-zag pattern along the waveguide (3). Baffles (10) counteract grating lobes. A fundamental mode of an electromagnetic field (E1) in the upper waveguide (2) excites only the transversal slots (7), which radiate a field (E3). The same fundamental mode (E2) in the lower waveguide (3) excites the slots (8) in the partition wall.

Abstract: A waveguide antenna comprising a waveguide in one wall of which a number of transversal slots are arranged. In connection with the transversal slots, electrically conducting waveguide elements are arranged which are located parallel to the wavelength wall and substantially symmetrically with respect to the transversal slots. In this way new slots are formed at the ends of the waveguide elements.

Abstract: A waveguide antenna (1) having a plurality of broad-side slots (S1-S3) is provided with one or more spatial filters (I, II) for suppressing the grid lobes (GL1,GL2) which occur in the radiated field as a result of the positioning of the slots. According to one embodiment, the spatial filter comprises two sections (I, II). The first section (I) comprises a box-like part which is mounted on the long side of the antenna waveguide (1) towards the slots (S1-S3) and has a height extension (a.sub.1) which is greater than or equal to the height extension (a) of the antenna waveguide. The other section (II) comprises two parallel walls which extend in the direction of the antenna axis. There is formed in this way an interface layer (G) which causes the grid lobes to be reflected back to the antenna aperture. A further embodiment of a spatial filter for the antenna waveguide is described.

Abstract: An impedance matching stripline transition for microwave signals which are conducted from a stripline circuit on one laminate (2) to another laminate (4) through a number of intermediate laminates (3). The connection between an incoming stripline circuit (21) on one laminate (2) to the outgoing stripline circuit (41) on the other laminate is performed as a short coaxial line. The outer conductor of the coaxial line is formed by a number of through-plated holes (12, 13, 23, 33, 43) in horseshoe form around a central conductor of through-plated holes (24, 34). The outer conductor is connected with the ground plane (31, 11, 45) of the laminates. They serve simultaneously as a suppressor of undesired modes in the microwave signals which are supplied to the transition via the conductor (21).

Abstract: An apparatus pressure treats a moving web by pressing the web against a surface. The apparatus comprises a continuous link chain and a chain support. The chain support supports a moving length of the chain close to the surface so the length of chain has a shape complementary to the shape of the surface. A length of web moving with the chain is pressed between the chain and the surface.

Abstract: An MTI-filter included in the receiver part of a tracking radar for suppressing clutter when receiving echo pulses from a certain target. The transmitting pulses of the tracking radar are transmitted in series where the carrier frequency is varied from pulse to pulse and is repeated from series to series. The MTI-filter (F) contains a number of delay links (DL1-DLN), for example digital shift registers which are stepped forward timely with the radar PRF. The input of the filter and the output of the shift register M.ltoreq.N are connected to a differentiator (SK) where M=the number of carrier frequencies in a pulse series.

Abstract: The invention relates to a method for a tracking radar which transmits radar pulses towards a certain target whose target range from the beginning is known. The carrier frequency of the transmitted radar pulses are during the target tracking varied from one pulse to the next following, so that a pulse series including a certain number M of carrier frequencies is treated. The number M is chosen with reference to the continuously measured target range and as long as this range is less than a certain value. If the target range exceeds this value the number M of carrier frequencies is changed and a new pulse series including this new number is transmitted. The unambiguous range to the followed target becomes dependent on the frequency repetition frequency in the transmitted pulse series instead of the PRF of the radar.

Abstract: An antenna includes a disk of dielectric material with a number of radiator elements and signal processing circuits. The radiator elements are arranged mirror-symmetrically with respect to two perpendicular axis and are divided into a number of sectors. When the antenna is a receiver a first part of the signal processing circuits is arranged in a first layer of the disk for combining signals emitted by the elements of any sector while a. A second part of the signal processing circuits is arranged in a second layer of the disk for combining signals coming from sectors similarly located with respect to the axes to groups of signals, each group of signals having at least one signal of generated sum signals and difference signals with respect to the two axes. A third and last part of the signal processing circuits is arranged in a third layer of the disk for combining in the groups of signals included sum signals and difference signals and for emitting the combined signals to the output terminals of the antenna.