Abstract: The present invention relates to an antenna arrangement connectable to a transceiver for transmitting and receiving RF signals in at least two separate frequency bands. The antenna arrangement has at least two sets of antenna elements arranged on a reflector, and the antenna elements are arranged in an interleaved configuration along a single column. The two separate frequency bands are substantially non-overlapping but relatively close to each other, and the distance between adjacent antenna elements in said column is substantially the same along the column.

Abstract: The present invention is related to a dual band antenna 1 comprising a number of antenna elements for transmitting and/or receiving radio frequency radiation. The antenna elements are placed above each other, and a shielded feeding means 9 is provided through a first antenna element 2 to a second antenna element 3 for separately feeding the different antenna elements 2, 3.

Abstract: A passive airborne mounted collision warning system suitable for light aircraft that enables an observer aircraft to determine the position of a nearby transponder-equipped target aircraft. The transponder-equipped target aircraft transmits replies responsive to interrogation signals from rotating secondary surveillance radars (SSR). In an embodiment of the invention, position of the target aircraft is determined based on the known position of the observer aircraft obtained e.g. via satellite navigation means such as GPS, the position of the SSR, and the bearing of the target aircraft measured by a direction finding antenna. The direction-finding antenna elements and the GPS receiver components are included in a device that is externally mounted on the observer aircraft. The data from the device is connected to a portable computer for processing and presentation to the pilot to alert him of the position of the target aircraft for avoiding collisions.

Abstract: A device for adjusting the beam direction of a beam radiated from a stationary array of antenna elements. The device includes a feed line structure configured as a star with at least four line segments extending from a central source connection terminal at the centre of the star, to the respective feed connection terminals. The dielectric body with two different body portions, having different effective dielectric values, is displaceable between two end positions in a central, region of the device.

Abstract: A passive airborne mounted collision warning system suitable for light aircraft that enables an observer aircraft to determine the position of a nearby transponder-equipped target aircraft. The transponder-equipped target aircraft transmits replies responsive to interrogation signals from rotating secondary surveillance radars (SSR). In an embodiment of the invention, position of the target aircraft is determined based on the known position of the observer aircraft obtained e.g. via satellite navigation means such as GPS, the position of the SSR, and the bearing of the target aircraft measured by a direction finding antenna. The direction-finding antenna elements and the GPS receiver components are included in a device that is externally mounted on the observer aircraft. The data from the device is connected to a portable computer for processing and presentation to the pilot to alert him of the position of the target aircraft for avoiding collisions.

Abstract: A device for adjusting the beam direction of a beam radiated from a stationary array of antenna elements. The device comprises a feed line structure configured as a star with at least four line segments extending from a central source connection terminal at the centre of the star, to the respective feed connection terminals (100). The dielectric body with two different body portions, having different effective dielectric values, is displaceable between two end positions in a central, region of the device.

Abstract: An antenna arrangement for receiving and/or transmitting electromagnetic signals in two spaced-apart frequency bands including a first frequency band having a first center frequency (f1) and a second frequency band having a second center frequency (f2). A first set of antenna elements (A1) are operative in the first frequency band (f1), and a second set of antenna elements (A2) are operative in the second frequency band (f2). A feeding network (C, 10, C1, C2) is arranged for feeding signals to the respective sets of antenna elements. The first set of antenna elements (A1) are arranged geometrically so that the first set has a first length (D1) in a first direction. The second set of antenna elements (A2) are arranged geometrically so that the second set has a second length (D2) in said first direction. In order to obtain lobes with the same beam width, said first and second lengths (D1, D2) are substantially inversely proportional to the first and second center frequencies (f1, f2).

Abstract: An aperture-coupled antenna, comprising at least one antenna element including a number of substantially planar, mutually parallel radiating patches (1-3) being fed with microwave power from a feed network (6) via an aperture (5a, 5b) in a ground plane layer (4). The feed network (6) feeds microwave power in at least two separate frequency bands, including a first, relatively low frequency band and a second, relatively high frequency band. A first patch (2) radiates microwave power in the first frequency band and is provided with an aperture (9a, 9b) so as to couple microwave power in the second frequency band to a second patch (1), the microwave power in the second frequency band being fed from the feed network (6) via the apertures (5a, 5b; 9a, 9b) in the ground plane layer (4) and the first patch (2) to the second patch (1).

Abstract: A substantially flat, aperture-coupled antenna element of the kind comprising a multilayer structure with a radiating patch (2) arranged on a dielectric layer (1), an electrically conductive ground plane layer (3) having a cross-shaped aperture (4) with two crossing slots (4a, 4b) being centered in relation to the patch, and a dielectric board provided with a feed network (6) for feeding microwave energy via feed elements (7, 8) and said cross-shaped aperture (4) to said patch so as to cause the latter to generate a dual polarized microwave beam propagating from the antenna element.

Abstract: A flat aperture-coupled antenna with a multilayer structure is disclosed. A rear side of the antenna comprises a metal reflector device including a hollow structure (3, 5) with separate box-like compartments, located in registry with radiating patches, corresponding pairs of orthogonal slots and feed elements, whereby microwave propagation within the hollow metal structure is substantially interrupted and any mutual coupling between the orthogonal slots is avoided.