High-Q coplanar waveguide (CPW) resonators are interesting not only for their direct applications as kinetic inductance detectors or with qubits for quantum information processing, but also because they are the simplest architecture to study the microscopic loss mechanisms and sources of decoherence in superconducting quantum circuits. Although state-of-art quantum circuits can perform many interesting computational tasks and demonstrate some challenging quantum phenomena, they are still considered quite noisy for real-world applications beyond the capability of classical computers. We aim to investigate the dominant loss mechanisms in superconducting resonators by corroborating the results of microwave measurements (quality factor, shift in resonance frequency, noise spectrum, …) with material characterization techniques. This union will provide us with deeper understanding of the fundamental properties governing the dynamics of the system and will pave the way towards building the new generation of superconducting quantum circuits.