Development of an electronic system for key parameter characterization of microwave SQUID multiplexers

Microwave SQUID multiplexer (μMUX) for transition-edge sensors achieves high multiplexing ratio, significantly reducing wiring complexity. However, the micro-nano fabrication technologies can lead to quality defects and non-functional channels during μMUX production. Therefore, comprehensive performance characterization is essential to identify defective channels prior to deployment and ensure reliable scientific data acquisition. This work proposes the design and implementation of a novel system for parameter characterization to address this need. The system employs an innovative critical polyphase filter bank architecture implemented on FPGA hardware to overcome computational bottleneck in broadband signal processing. By systematically combining results measured at different local-oscillator frequencies, this approach addresses transition band attenuation inherent in critically sampled filter banks. The use of combined synthesis-analysis filter banks enables broadband signal generation and channelization. The developed prototype system achieves a phase noise of at for the probe tone. This system provides an optional solution for per-channel screening of μMUX chips, enabling the identification and rejection of nonfunctional or substandard chips.