RF methods for adaptive cancellation of cross polarisation in microwave satellite systems
Abstract
The expected capabilities and limitations of unitary cancellers are summarized on the basis of existing knowledge of microwave propagation in ice and rain, and the construction of a new prototype X-band device is described. Two new results, concerning a two-parameter canceller which yields large improvements in isolation and the case of an ice medium in which the principal plane angle and the differential phase shift are correlated, are briefly discussed. The new prototype uses a four-vane differential phase shifter which simultaneously moves the four vanes by means of a system of four metal links in a diamond formation. The gearing and screw can change the differential phase shift at a maximum of 30 deg per second. The absolute insertion loss of the shifter was measured as less than 0.25 dB under all conditions and for either rexolite or perspex untampered vanes between 9.4 and 12.4 GHz.
- Publication:
-
2nd International Conference on Antennas and Propagation
- Pub Date:
- 1981
- Bibcode:
- 1981icap.conf..188M
- Keywords:
-
- Cancellation Circuits;
- Cross Polarization;
- Microwave Equipment;
- Microwave Transmission;
- Rain;
- Satellite-Borne Instruments;
- Frequency Reuse;
- Ice;
- Phase Deviation;
- Superhigh Frequencies;
- Communications and Radar