Investigation of IMD3 in GaN HEMT based on extended volterra series analysis

This paper mainly focuses on providing theoretical justification for possible GaN device linearity improvement, interpretating key physical origins of IMD3. Based on bias dependent S-parameter measurement data of field-plate-free 8x125 mum GaN HEMT, IMD3 is modelled using classical Volterra series theory. Device diagnosis is hence carried out, by means of this technique, for efficiently localizing the distortion behaviour. Further, device linearity is shown to improve by appropriately tuning gate-drain feedback capacitance by taking advantage of field-plate technology proving the analysis to be a powerful tool for developing GaN HEMT technology. Further, with the intension of understanding IMD nulling, Volterra analysis is extended to 5th-degrce nonlinearity through which an insight into the distortion cancellation mechanism is obtained.