%0 Journal Article
%T Transformer Coupling and Its Modelling for the Flux-Ramp Modulation of rf-SQUIDs
%A Andrea Giachero
%A Andrei Puiu
%A Angelo Nucciotti
%A Claudio Gotti
%A Elena Ferri
%A Gianluigi Pessina
%A Lorenzo Cassina
%A Marco Faverzani
%A Matteo Maino
%A Paolo Carniti
%J -
%D 2019
%R https://doi.org/10.3390/instruments3010003
%X Abstract Microwave SQUID (Superconducting QUantum Interference Device) multiplexing is a suitable technique for reading a large number of detector channels, using only a few connecting lines. In the HOLMESexperiment, this is based on inductively coupled rf-SQUIDs fed by TES (Transition Edge Sensors). Operation of the whole rf-SQUID chain is achieved with a single transmission line, by means of the recently introduced flux-ramp modulation technique¡ªa sawtooth signal which allows signal reconstruction while operating the rf-SQUIDs in an open loop condition. Due to the crucial role of the sawtooth signal, it is very important that it does not suffer from ground-loop disturbances and electromagnetic interference (EMI). Introducing a transformer between the sawtooth source and the SQUID is very effective in suppressing disturbances. The sawtooth signal has both slow and fast components, and the frequency can vary between a few kHz up to a MHz, depending on the TES signal and SQUID characteristics. A transformer able to handle such a broad range of conditions must have very stringent characteristics and needs to be custom designed. Our solution exploits standard commercial and inexpensive transformers for LAN networks, stacked in a user-selectable number, to better fit the bandwidth requirements. A model that allows handling of the low- and high-frequency operating range has been developed. View Full-Tex
%K EMI suppression
%K analogue electronic circuits
%K microwave multiplexing system
%K rf-SQUIDs
%K TES detectors
%K high frequency transformer modeling
%U https://www.mdpi.com/2410-390X/3/1/3