Broadband Calculable Coaxial Resistors

This article describes a method to model the impedance of a Haddad-type resistor over a frequency interval ranging from 10 to 200 MHz, hereafter defined as low frequency–radio frequency (LF–RF) range. To this end, novel resistor standards, of <inline-formula> <tex-math notation="LaTeX">$1 \rm k \Omega $ </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">$100 \Omega $ </tex-math></inline-formula>, have been designed and manufactured with the aim of sharply identifying the nodes that define the impedance. Resistor modeling is divided into two main parts: the first one, describing the central coaxial core and the second part, describing the connectors through physical simulations and a subsequent analytical approach. The results show a remarkable good agreement between measured and modeled impedance over the whole considered frequency range. Uncertainty values allow for the traceability of the resistors up to high frequencies and for the calibration of commercial impedance analyzers within the LF–RF range.