A non linear vector corrected measurement system for device and system characterisation

This paper describes a vector corrected nonlinear measurement system based around a microwave transition analyser and spectrum analyser. This system can be used to measure intermodulation distortion as well as device output harmonic performance under different drive levels, DC bias and fundamental load impedance conditions. The system can also plot the dynamic load lines during measurement. Three applications of the system will be described showing it's versatility in large signal measurements. Firstly, the system will be used to study harmonic generation in HEMT devices, identifying the causes for harmonic nulls in the second and third harmonics with increasing input power and their direct relation to the output IV curves. Secondly the system will be used to measure the phase modulation behaviour of a 5.8 GHz injection locked MMIC oscillator, and finally the systems use in characterising the IMD performance of an active device in the bias plane is described.