  We have developed a cryogenic platform for the control and readout of spin
qubits that comprises a high density of dc and radio frequency sample
interconnects based on a set of coupled printed circuit boards. The modular
setup incorporates 24 filtered dc lines, 14 control and readout lines with
bandwidth from dc to above 6 GHz, and 2 microwave connections for excitation to
40 GHz. We report the performance of this platform, including signal integrity
and crosstalk measurements and discuss design criteria for constructing sample
interconnect technology needed for multi-qubit devices.
