In a meanderline array random-polarizer comprising a plurality of stacked substantially identical arrays of laterally spaced square-wave shaped conductive strips or meanderlines arranged with parallel extending axes with each such axis spaced one array-period from its nearest counterparts, the improvement consisting of offsetting or staggering the meanderline axes of adjacent arrays by a distance preferably equal to one-half of the array-period. The meanderline axes in one set of alternate arrays are thus aligned in parallel planes spaced apart by an arrayperiod; the meanderline axes in the remaining or second set of alternate arrays are also aligned in parallel planes spaced apart by one array-period; and the second set of parallel planes are offset or staggered by a distance equal to one-half of an arrayperiod from the first set of parallel planes. A polarizer comprising a plurality of such staggered arrays has utility when placed in front of the aperture of pyramidal horn antenna for converting the linearly polarized wave of the horn to a circularly polarized wave.

Broadband antenna polarizer

This relates to a mat-strip dual circularly polarized phased antenna array with independent steering of both right hand circularly polarized and left hand circularly polarized antenna beams. This is obtained by superimposing in a common aperture two linearly polarized phased arrays with their dipole element axis in space quadrature and by setting one polarizer over both linearly polarized arrays. The two circularly polarized antenna beams can be independently and simultaneously scanned, operated in transmit or receive, operated at different frequency and be designed for different bandwidth, gain and slidelobe characteristics. The beams are oppositely polarized through the use of a single polarization device interposed over orthogonal linear arrays. The linearly polarized arrays are phased by a separate phase shifter coupled to the mat-strip power division distribution network of each of the arrays, by providing one or more mat-strip phase shifter which can be controllably connected into the distribution network and/or by controlling the manner in which the distribution network is connected to the mat-strip dipole elements of the array.

Circularly polarized phased antenna array

A re-polarization means for generating circular polarized electro-magnetic waves using single or multi-layer lattice structure mounted in front of a radiation aperture with the lattice structure comprising a plurality of conductors which extend parallel to each other and/or meander shaped and wherein the lattice structure has one or more additional layers which are closer to the radiation aperture and which has a plurality of parallel conductors but that are inclined by an angle of 45° relative to the direction of the conductors mounted on the other layers which meander. Additionally, orthogonal polarization suppression is achieved with the apparatus of the invention. The invention can be applied to a radom of a target tracking radar antenna, for example.

Polarization means for generating circularly polarized electro-magnetic waves

Einrichtung zur Umwandlung elektromagnetischer Wellen mit einer gegebenen Polarisation in solche mit zirkularer Polarisation unter Verwendung eines sogenannten Zirkularpolarisationsgitters. Means for converting electromagnetic waves of a given polarization into those with circular polarization by using a so-called circular polarization grating. Dieses besteht aus mehreren schichtartig ubereinander angeordneten Gitterstrukturen aus Leitern in Form von periodischen und im wesentlichen parallel zueinander verlaufenden Maanderlinien (4 bis 10). This consists of several layer-like manner one above the other arranged lattice structures of conductors in the form of periodic and substantially parallel to one another meander lines (4 to 10). Die Elliptizitat der Zirkularpolarisation, welche durch ein solches Gitter erzeugt wird, wird uber die gesamte Bandbreite dadurch erheblich verringert, das die maanderformigen Leiterstrukturen (6,7,8) von mindestens einer der Gitterstrukturen hinsichtlich ihres geometrischen Verlaufs nicht alle gleichphasig sind, sondern einen Phasenversatz zwischen jeweils benachbarten Linien aufweisen. The ellipticity of the circular polarization, which is produced by such a grating, is thereby substantially reduced over the whole range that the meandering conductor patterns (6,7,8) of at least one of the grating structures do not all have the same phase with respect to their geometrical course, but a phase shift comprise between adjacent lines. Das Zirkularpolarisationsgitter ist insbesondere zur Integration in eine Radom einer Zielfolgeradarantenne geeignet. The circular polarization gratings is particularly suitable for integration in a radome of a target tracking radar antenna.

Arrangement for transforming the polarization of electromagnetic waves

There are herein described microwave devices that are mounted at the output ends of circularly polarized horn antennas of a microwave antenna array. The devices act as coupling compensators between the horns, and also function as singular or dual polarization trimmers to create very low axial ratio circularly polarized antenna array patterns through a broad angular range. In each of these devices, a parasitic element is disposed on a planar substrate that is orthogonally positioned with respect to the direction of propagation from the horn antennas.

Coupling compensation device for circularly polarized horn antenna array

A BROADBAND CIRCULARLY POLARIZED ANTENNA HAVING A CONTINUOUS RECTANGULAR APERTURE TO OBTAIN CIRCULAR POLARIZATION, HAVING UNIFORM PHASE AND TAPERED AMPLITUDE ILLUMINATION OVER THE BROAD DIMENSION OF THE APERTURE. THE DEVICE FEATURES A LARGER EFFECTIVE RADIATING OR RECEIVING APERTURE THAN COMPARABLE RECTANGULAR ARRAY OF CIRCULARLY POLARIZED SPIRALS DUR TO THE USE OF VIRTUALLY LOSSLESS RADIATING ELEMENTS TO PROVIDE HIGHER GAIN. LINEARLY POLARIZED RADIATING ELEMENTS ARE UTILIZED TO FEED AN APERTURE WITH LINEARLY POLARIZED ENERGY WHICH IS THEN TRANSFORMED INTO CIRCULARLY POLARIZED ENERGY BY MEANS OF A POLARIZER GRID.

Tsze K Lee

Papers

Broadband circularly polarized antenna having a continuous rectangular aperture