Stripline resonators for cryogenic microwave spectroscopy on metals and superconductors

Microwave spectroscopy is a powerful experimental tool to study the electrodynamics of metals and superconductors at comparably low frequencies. To overcome some disadvantages of the established cryogenic microwave techniques, we use stripline resonators as a probe where the bulk sample under study represents one of the ground planes of the transmission line. We discuss striplines made of copper as well as superconducting lead, and we show the applicability of this technique with measurements at the superconducting transition of a bulk sample of tantalum.