An Agile Microwave Frequency Synthesiser with High Spectral Purity

The key performance features of microwave frequency synthesisers for future radar systems are outlined and a source employing a new technique to meet these requirements is described, which provides a stable, coherent high spectral purity output frequency with agility over multiple channels. The source uses a hybrid configuration which has at its core a dividerless translation loop. This phase lock loop exhibits wide loop bandwidth conveying fast switching and the elimination of loop multiplicative degradation to phase noise, whilst the hybrid configuration enables the provision of fine frequency resolution via a direct synthesiser. The design and performance of a demonstration frequency synthesiser are described.