Quality factor of a transmission line coupled coplanar waveguide resonator

摘要

We investigate analytically the coupling of a coplanar waveguide resonator toa coplanar waveguide feedline. Using a conformal mapping technique we obtain anexpression for the characteristic mode impedances and coupling coefficients ofan asymmetric multi-conductor transmission line. Leading order terms for theexternal quality factor and frequency shift are calculated. The obtainedanalytical results are relevant for designing circuit-QED quantum systems andfrequency division multiplexing of superconducting bolometers, detectors andsimilar microwave-range multi-pixel devices.