MODE COUPLER IN AN AUTOMATIC ANGLE TRACKING SYSTEM

摘要

the invention relates to a mode coupler which, for example is included in an angle tracking system of a satellite to establish a telecommunication between the transmitting and the receiving ground stations. The mode coupler is realized through a circular main wave guide (1) which also can include the feeding horn of the satellite antenna in which a basic mode, for example the TE11-mode of the incoming circular polarized wave guide field appears and which procures two communication channels (f1-f2 and f3-f4 respectively), as well as a beacon frequency (fb). To the main wave guide four rectangular wave guide arms (2a-2d) are connected via the associated apertures (3a-3d). The main wave guide is dimensioned as a mode filter for filtering away the non-desired higher modes TE21 and TM01 and the wave guide arms are dimensioned as a frequency filter for filtering away the frequency bands of the communication channels. From the higher modes TE21 and TM01, the difference- and the sum signals are created in known way to provide a measure of the angle error of the satellite antenna.