Abstract: The invention discloses an antenna (100, 100?, 400, 500) comprising walls in a conducting material: first (110, 410, 510) and second (120, 420, 520) main walls, a first end wall (130, 530) and a first and a second side wall. The first (110, 510) and second (120, 520) main walls extend in parallel to each other, and are joined by the first end wall (130, 530). The side walls also join the first and second main walls, so that a cavity with only one opening (105, 205, 505) is formed, a rectangular aperture which can be brought to radiate by a feed connection (207). Suitably, the antenna can also comprise a second end wall (140, 540) which extends from the second main wall (120) towards the first main wall (110), with the length of extension of the first main wall being such that the second end wall and the first main wall do not meet.

Abstract: The invention discloses a radar system (100) for the detection of low RCS-objects (110, 140, 150, 160, 190) such as forest fires, said system comprising a first plurality of stations (120) for transmitting radar energy, said stations having mechanically fixed antennas (220), and a second plurality of receive stations (130) for receiving reflections of radar energy transmitted from the transmit stations, said stations having mechanically fixed antennas (220). The antennas (220) of said transmit and receive stations have a main beam (221) which is essentially parallel to the ground, and at least a sub-set of the receive stations is equipped with means for recording a first and a second received signal, and means for subtracting one of said signals from the other of said signals. Said transmit and receive stations are arranged to function within the frequency range of 10-100 MHz.

Abstract: A self-complementary patch antenna is disclosed. A hexagonal lattice (10) consisting of triangular conducting patches (1) is formed together with at least one dielectric layer onto a ground-plane. Each triangular patch is then fed by means of three RF signal probes in a symmetrical configuration positioned near each corner of the triangle, whereby an arbitrary lobe-steering and polarisation state can be established by selection of amplitude and phase for each RF signal probe.

Abstract: A dual polarised wave-guide notch antenna array is disclosed. The device comprises a feed section (1) having at least two input transmission lines, a feed/wave-guide interface (5) providing an aperture for transferring a radio frequency electromagnetic wave between the feed section (1) and a wave-guide mode in a wave-guide section (3) having ridges. The wave-guide section transfers energy between the feed/wave-guide interface and a tapered notch section (7), thereby gradually adjusting a created electromagnetic field towards free space conditions.

Abstract: The present invention relates to a broadband non-resonant antenna device for wireless transmission of information using electromagnetic signals, comprising a metal sheet layer, forming a plane, with a slotline that comprises a first part and a second part. The side of the second part that is the most distant from the first part transcends into a widening open-ended tapered slot in the metal sheet layer. The device additionally comprises a feeding line in the metal sheet layer. The feeding line comprises a feeding part, with a first end and a second end, and gaps separating the feeding part from the surrounding metal sheet layer by a certain distance, where the slotline is intersected by the feeding line.

Abstract: The invention relates to an antenna device comprising a group antenna (310) with radiating elements (340-347) in M rows and N columns M, where N<M, which group antenna (310) has a width measurement (b) and a height measurement (h). The group antenna (310) is so arranged in the antenna device that the projection (P) of the group antenna in the sideways direction of the antenna in the horizontal plane (210) exceeds the width measurement (b) of the group antenna, whereby the group antenna is given a narrower main lobe in the horizontal plane (210).

Abstract: The invention relates to an antenna device comprising a group antenna (310) with radiating elements (340-347) in M rows and N columns M, where N<M, which group antenna (310) has a width measurement (b) and a height measurement (h). The group antenna (310) is so arranged in the antenna device that the projection (P) of the group antenna in the sideways direction of the antenna in the horizontal plane (210) exceeds the width measurement (b) of the group antenna, whereby the group antenna is given a narrower main lobe in the horizontal plane (210).