Superconducting circuit quantum electrodynamics experiments with propagatingmicrowaves require devices acting as beam splitters. Using niobium thin filmson silicon and sapphire substrates, we fabricated superconducting 180{\deg}microstrip hybrid ring couplers, acting as beam splitters with centerfrequencies of about 6GHz. For the magnitude of the coupling and isolation wefind -3.5+/-0.5dB and at least -15dB, respectively, in a bandwidth of 2GHz. Wealso investigate the effect of reflections at the superconductor-normalconductor contact by means of low temperature laser scanning microscopy. Ourmeasurements show that our hybrid rings are well suited for on-chipapplications in circuit quantum electrodynamics experiments.
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