Amplitude modulated scanning antenna system - includes filters for smoothing ripple in amplitude modulating signals

摘要

The antenna system forms a cluster of closely spaced beams filling a desired angular scan sector. A transmit signal amplitude applied to each beam is modulated as a function of time to form a composite beam which scans smoothly across the scan sector. The RF transmit signal is initially split into a number of equal amplitude signals and fed to a number of attenuators by power dividers for selective amplitude modulation of the RF signals. The amplitude modulating signals are supplied to the attenuator by a digital controller, which also supplies switch control signals to selectively switch amplitude modulating transmit signals of varying amplitude to selected feed elements of an array of radiating elements in a time sequence for feeding an antenna reflector.