Analysis of an Analog Bipolar multiplier at cryogenic and room temperature

This thesis studies the behaviour of a Gilbert cell multiplier higher order. The investigations has been carried out by means of mathematical modelings and circuit simulations at both room (RT) and cryogenic (CT) temperature. The aim of this comparative approach is to distinguish the operational behavior of the circuit in a cryogenic environment, in which the device is expected to operate when integrated into quantum processing unit. The circuits have been indeed implemented in the 130nm SiGe BiCMOS SG13G2 tecnology by Innovation for High Performance (IHP) Microelectronics (Frankfurt am Oder, Germany), whose Design Kit makes available both RT and CT models. In addition, a similar investigation has been applied to a Jones modulator, implemented in the same technology. Then, a comparison between the Gilbert cell and the Jones modulator will be carried out in terms of harmonic amplitude and SFDR. Finally, a complete characterization of the Gilbert multiplier in terms of figure of merits to give a complete view on the circuit.