Practical linearity evaluation of vector network analyzer at RF

This paper describes a method to evaluate the receiver linearity of a vector network analyzer (VNA). Linearity is important for transmission and reflection measurements. The method employs a voltage doubler which provides an absolute 6.0206 dB value in some test levels, and a simple 6 dB step attenuator measurement which provides a relative 6 dB value over wide test signal levels. Receiver linearity was evaluated within 0.001 dB to 0.01 dB at absolute 6 dB steps over wide test signal levels, since the 6 dB step attenuator was calibrated using the same levels which have been evaluated to within 0.001 dB by a voltage doubler method up to 18 GHz.