Impedance measurement methodology for small antennas: Application to two different designs

Conventional feeding coaxial cable can affect the impedance measurement of small antennas. Rather than trying to eliminate the disturbing cable, a technique based on the characterization of the cable effect has been used recently for the accurate measurement of electrically small antenna impedance. In this paper we discuss about the use of this methodology for two antenna designs with different sizes, impedance and cable influence. The issues related to the use of a feeding coaxial cable in both simulation and prototype characterizations are firstly highlighted. Then the methodology to extract the isolated antenna impedance from measurements is applied and discussed.