Dual probe use for the remote measurement of an antenna under test

This paper explores an alternative to the previous remote impedance measurement of antennas to improve the dynamic range of the needed data for the measurements. Previous work evaluated the refection coefficient of a source antenna as a function of the termination on the antenna under test (AUT). The loads used in the measurement are the classic open-short-load, with measured data used for the actual termination impedances. The impedance of the AUT is determined by a standard calibration approach. For current vector network analyzers, the dynamic range of the analog-to-digital converter limits the impedance estimate, particularly if the distance between the source and AUT is increased to reduce interaction affecting the impedance of the AUT. The new approach separates the transmit and receive functions to allow the use of a LNA to improve the receive signal strength and offer the opportunity to overcome some of the limitations of the reflection approach.