Short-end probe for accurate permittivity measurements with time domain reflectometry

An investigation is presented on the use of short-circuit terminations in two-wire trasmission lines employed as probes in standard Time-Domain-Reflectometry (TDR) setups. Experimental permittivity results are given for different configurations and materials, and these data are compared with those achievable using conventional open-type terminations. The possibility of both improving the accurancy and simplifyng the procedures of TDR measurements using shorted-end probes is illustrated.