High data-rate millimetre-wave modulator modelling and design

In this paper a linear and nonlinear model for microwave modulator has been realized and discussed. The model is thought to be applied to modern high data rate digital communications. The model is specialized to the widely used direct conversion quadrature modulator architecture. The EVM, Image and LO rejection performances are modelled and estimated for QAM modulation schemes. Design charts have been extracted to help the design of the building blocks of the modulator. To validate the model a 45GHz - 65GHz MMIC vector modulator, based on a doubly balanced star mixer, has been designed using 0.2 commercial PHEMT process.