Non-linear characterisation of microwave devices

At the present time there is an increasing demand for high frequency electronic systems that involve the operation of semiconductor devices under conditions where their non-linear behaviour will affect system performance. To correctly predict system performance it is thus necessary to both characterise and model the non-linear behaviour of semiconductor devices under large signal high frequency excitation. Over the last 10 years´ time domain measurements at microwave frequencies have been perfected to the point that they cart now provide full two-port vector corrected measurement over a broad bandwidth; such measurement systems are collectively referred to as Non-Linear Vector Network Analysers (NLVNAs). NLVNAs provide an ideal tool for investigating the large signal behaviour of semiconductor devices. This paper discusses the realisation of an NLVNA and provides an indication of how it can be used both in the investigation of large signal circuit behaviour and for the extraction of non-linear models