  We have designed and fabricated superconducting coplanar waveguide resonators
with fundamental frequencies from 2 to $9 \rm{GHz}$ and loaded quality factors
ranging from a few hundreds to a several hundred thousands reached at
temperatures of $20 \rm{mK}$. The loaded quality factors are controlled by
appropriately designed input and output coupling capacitors. The measured
transmission spectra are analyzed using both a lumped element model and a
distributed element transmission matrix method. The experimentally determined
resonance frequencies, quality factors and insertion losses are fully and
consistently characterized by the two models for all measured devices. Such
resonators find prominent applications in quantum optics and quantum
information processing with superconducting electronic circuits and in single
photon detectors and parametric amplifiers.
