Polarization effects of the secondary mirror of a variable profile antenna.
Abstract
Field-amplitude distributions and electric-vector rotation angles at the aperture of a variable-contour antenna (VCA) are calculated taking into account the effect of a secondary reflector in the form of an asymmetric parabolic cylinder. The polarization characteristics of a VCA are analyzed for the case where circular polarization is measured. Two cases are distinguished: (1) the VCA is pointed at the horizon, where the primary reflector has no effect on polarization, and (2) the VCA is pointed at a certain altitude, where the primary and secondary reflectors exert combined polarization effects. Some measures are proposed for upgrading the secondary reflector with the aim of decreasing the effect of this reflector on polarization measurements with a VCA.
- Publication:
-
Astrofizicheskie Issledovaniia Izvestiya Spetsial'noj Astrofizicheskoj Observatorii
- Pub Date:
- 1979
- Bibcode:
- 1979AISAO..11..170K
- Keywords:
-
- Circular Polarization;
- Mirrors;
- Polarization Characteristics;
- Radio Telescopes;
- Two Reflector Antennas;
- Amplitudes;
- Antenna Radiation Patterns;
- Variable Geometry Structures;
- Vector Analysis;
- Astronomy;
- Polarization:Radio Telescopes