Modulation for HF swept beams - employs amplitude and phase modulation and sequential switching to fixed array

摘要

Modulation system for the power supplied to phase fed antennae systems, providing a narrow continuous swept beam at micro wave frequencies. The antennae array to be fed has, for example, 16 elements fed sequentially by four digital type phase modulators spaced at 22 deg. 30'. Each such modulator feeds an amplitude modulator which is coupled into four individual antennae elements distributed through the sixteen element array by a single switch. The four parallel modulation chains are fed from a common RF power source, the modulation providing an output which is determined by calculation of distributed current to produce the beam required, the conjugate of the current and amplitude limitation.