General information
Nowadays, there is a trend towards the widespread use of wireless devices for various applications, from data networks to wireless sensors. To find and characterize wireless devices, it is necessary to survey the surrounding environment. This becomes a problem when characterizing the properties of the RF circuit: when a two-dimensional signal is transmitted to an RF device, it is affected by nonlinear components of the circuit, amplifiers and diodes. Nonlinear components cause intermodulation distortion of the input signal, which is re-radiated by the device. The features of the intermodulation distortion result are used to build a fingerprint of the device. The fingerprint is then used to characterize the device so that it can be identified among other RF devices.
