In-circuit characterisation technique for barritt diodes and other 2-terminal negative-resistance oscillator devices

The large-signal characterisation of 2-terminal, solid-state oscillator devices operating in microwave circuits may be achieved using a technique for measuring the circuit admittance seen from the device chip. The method provides a means of making such a measurement with the minimum of assumptions, especially in respect of the encapsulation. Results are presented in the form of a 3-dimensional ‘device surface’ of the complex admittance as a function of frequency and r.f. amplitude.