RF Front-Ends Nonlinearity Characterization Using Reflected Power

The electromagnetic susceptibility to third-order intermodulation (IM3) of radio-frequency (RF) receiver front-ends is studied. Two-tone test is the most widely used nonlinear distortion characterization method. It produces IM components in operating bands of RF front-end, which are called in-band IM products and are caused by system nonlinearities. It is proposed here to measure the IM3 signal reflected by the system when two-tone excitation is applied to the antenna port. The method is shown to agree well with standard estimations of the nonlinear properties of various radio receiver front-ends with different designs. Devices are compared in terms of susceptibility to intermodulation.