Phase noise

One of the more unusual discoveries made during the investigation of novel Gunn devices was that of semi-chaotic behaviour in which the device produces very broadband, noise-like output. This has potential application as a noise source and a spread spectrum communications transmitter.

Recently we have developed an interest in using multiplied oscillators at lower frequencies (eg DROs and YTOs at around 7.5GHz) to generate 94GHz with better phase noise and improved long term stability than a 94GHz Gunn diode. These have been used in measurement systems (eg, a purpose built system for characterising cavities), FMCW radars and in our EPR spectrometers. An example phase noise plot comparing a multiplied YTO with a 94GHz Gunn diode is shown below.



As well as Gunn diodes and multiplied sources, we also make extensive use of our W-band backward wave oscillator, especially in our materials characterisation experiments. More information about our microwave and mm-wave resources can be found on our facilities page.