Intrinsic phase noise properties and frequency stability of millimetre-wave module at 90 GHz

A report is presented on the residual intrinsic phase noise properties of a millimetre-wave module used to generate W-band signals from an X-band analogue signal generator. The 90 GHz outputs of two nominally identical millimetre-wave modules are heterodyned to measure their instantaneous frequency fluctuations and hence infer the close-to-carrier phase noise. The fractional frequency stability at 1 s integration time is 2 × 10^-14, which corresponds to a total single-sideband phase noise of -50 dBc/Hz at 1 Hz Fourier frequency offset from the carrier and a residual single-sideband phase noise of -52 dBc/Hz at 1 Hz offset.