Calibration of EM simulator on substrate complex permittivity

A novel broadband non-resonant Thru-Line (TL) technique is proposed for the extraction of substrate complex permittivity, while the influence of the end-launch connectors is fully suppressed. The main difference to the traditional TRL techniques is that only two calibration standards are needed and the length difference between Thru and Line is much larger than a quarter of a wavelength at the central frequency of the band. The larger effective line length increases sensitivity to the substrate losses, and allows accurate measurement at lower frequencies. The technique uses the measured propagation constant in a 3D EM field simulator for the complex permittivity extraction. This TL technique has been verified experimentally for microstrip and grounded coplanar waveguide transmission lines using RO4350B substrate in the frequency range 45 MHz - 26 GHz. A ring resonator coupled to microstrip line was used as the verification DUT.