Direct-division phase-lock loop at 12 GHz

The paper presents the realisation of a 12 GHz phase-lock loop, using dividers to compare the output frequency with a much lower reference frequency. This was made possible through the application of hybrid microwave technology to the oscillator and divider circuitry. Measurements are reported and the noise budget is analysed in detail. This PLL is important for frequency synthesisers and local oscillators in digital radio links, radar equipment and satellite communications.