《Accurate Characteristic Impedance Measurement on Silicon》.pdf

Accurate Characteristic Impedance Measurement on Silicon Dylan F. Williams National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80303 Ph: [+1] (303)497-3138 Fax: [+1] (303)497-3122 E-mail: dylan@boulder.nist.gov Uwe Arz and Hartmut Grabinski Universität Hannover, D-30167 Hannover, Germany Ph: [+49] 511.762.5030 E-mail: uarz@lfi.uni-hannover.de, hgra@lfi.uni-hannover.de Abstract- This paper presents a new method that calibration to those of an ideal transmission line. accurately determines the characteristic impedance However, the probe-tip calibration measures not only of planar transmission lines printed on lossy the scattering parameters of the line, but also of the dielectrics even when contact-pad capacitance and contact pads or other unaccounted for transition conductance are large. We demonstrate the method parasitics. This method of determining Z0 is on a coplanar waveguide fabricated on fused silica particularly sensitive to the shunt contact-pad and a microstrip line fabricated on a highly capacitance. To circumvent this drawback, [3] suggests conductive silicon substrate. measuring the capacitance of the contact pads separately and subtracting their effect from the data INTRODUCTION measured by the probe-tip calibration before