Telefonaktiebolaget Lm Ericsson (Publ)

Lars G Josefsson

Jan-Olov Winnberg

Lars F Moeschlin

Karl-Erik I Oderland

Per Ligander

Anders Derneryd

Bengt Inge Svensson

Björn Johannisson

Björn Thors

Lars Bertil Malm

Karl A Andersson

Jan Michael Bergendahl

Bengt T Svensson

Mats Gunnar Eriksson

A waveguide arrangement having a longitudinal extension, along which an electromagnetic wave may propagate, and comprising at least one waveguide part and a feeding arrangement which is arranged for feeding said waveguide part with a first polarization and a second polarization, said polarizations being mutually orthogonal. The feeding arrangement comprises a dielectric carrier material comprising a first feeding conductor, feeding the first polarization and a second feeding conductor, feeding the second polarization, where the first polarization is excited by means of first excitation means fed by said first feeding conductor and the second polarization is excited by means of second excitation means fed by said second feeding conductor, where at least one excitation means is a symmetrical structure with respect to the longitudinal extension.

Dual polarized waveguide feed arrangement with symmetrically tapered structures

A method and an antenna arrangement are disclosed for reducing the antenna radar cross section for an externally illuminating radar source. A radar pulse is transmitted with the antenna arrangement fully matched to achieve a lowest possible power loss of the pulse. At all other times the antenna will be poorly matched and thereby will act as a low radar cross section. The reduced radar cross section leads to an antenna gain reduction, which most often can be accepted since competing noise is reduced as much as the useful signal. It is further suggested that the range gate of the receiver and the transmitter pulse control the antenna. Thus, the antenna is 'fully opened' during the transmitting pulse and may be partly or 'trade-off' matched during range gate reception. In the interval of not transmitting or receiving, the antenna will present a low radar cross section.

Dynamic antenna

The present invention relates to an omnidirectional base station antenna arrangement with a number of antenna elements and a number of transceiver means for transmitting and receiving signals to/from a number of user stations. A feeding network is provided which comprises a number of phase ports, a number of which form first phase ports connected to a number of transceiver means for downlink communication and a number of which form second phase ports connected to a number of transceiver means for uplink communication. The feeding network comprises a number of antenna ports connected to antenna elements and the feeding network generates substantially independent, orthogonal signals to provide for phase diversity and the antenna elements are arranged to form at least one cylindrical array antenna. The invention also relates to a method of providing communication between an omnidirectional base station antenna arrangement with a number of antenna elements and a number of transceiver means and a number of user stations as well as to a method of providing for at least phase diversity transmission at an omnidirectional base station antenna arrangement.

Antenna arrangement and method relating thereto

A device for the power transmission of microwaves between a strip-line and a number of parallel cavity waveguides arranged in a group antenna. The strip-line includes H-shaped slots. These slots are centered with respect to a central conductor. Opposite each of the slots, a corresponding slot is arranged through the wall of the cavity waveguide. Electrically conducting seals are arranged to follow immediately outside the contours of the slots. The strip-line is fixedly fastened to the seals and the ridge waveguide, whereby good electrical coupling is achieved. Simultaneously, small cavities are formed between the slots. These cavities have a leveling effect such that the demands on mechanical precision is appreciably lowered, such that the tolerance to placement of the slots opposite to each other is increased substantially as compared to the case of the waveguides directly abutting the strip-line.

Microwave antenna transmission device having a stripline to waveguide

Array antenna has a number of radiating elements and is provided with an arrangement to reduce the reflection of the incident radiation in a direction opposite to that of the incident radiation. The arrangement includes electrically conducting elements which are located between the radiating elements and substantially parallel to the electrical field of the radiating elements.

Array antenna

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. These latter slots radiate a field (E4) which excites only the upper longitudinally extending slots (6), which radiate a field (E5). Supply of the fundamental modes (E1, E2) and also the radiated fields (E3, E5) are independent of one another and a desired polarization can be obtained. A radiated lobe is symmetric and the radiated fields (E3, E5) can carry individual information.

Waveguide antenna which includes a slotted hollow waveguide

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.

Waveguide antenna with transversal slots

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.

Waveguide antenna having a plurality of broad-side slots provided with a

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).

Impedance matching stripline transition for microwave signals

MTI-Filter in a trackding radar receiver

Method in a tracking radar to attain a large unambiguous range for

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.

Growing community of inventors

Askim, Sweden

Lars G Josefsson