Systematic Deembeding of the Transmission Line Parameters on High-density Substrates with Probe-tip Calibrations

Three procedures allowing the systematic determination of the propagation characteristic of lines and deembedding the influence of feeding discontinuities are presented. All of them are based on the known measurement technique of two lines with different lengths on the measured substrate after earlier calibration with standard substrate. The first one doesn’t involve the knowledge of the reference planes location and their shift to the probe tips in the extraction process and allows arbitrary position of the probe tips along the lines (not necessarily located at a position approximately in front of the physical beginning of the lines). In effect equivalent element models of error boxes representing the feeding discontinuities don’t have to be lumped models. The second one is a modified procedure from [4], wherein the probe-tip discontinuity error box is modeled by RLCG element. This new formulation allows to omit one of the limitations of the S-matrix asymmetry of an arbitrary reciprocal junction (in our case probe-tip discontinuity). This limitation is a complex characteristic impedance of the meausred lines. The third procedure allows to determine the characterisitc impedance of the lines with the wider or narrower pitch than that of the used probes. The complex propagation constant and characteristic impedance have been determined for lines on fused silica substrate up to 110GHz and error box modesl have been verified up to this frequency range.