Automatization of compression point 1dB (CP1dB) and input 3rd order intercept point (IIP3) measurements using lab VIEW platform

Compression point 1dB (CP1dB) and input 3rd order intercept point (IIP3) are useful parameters to characterize the nonlinear property of RF devices. Automatization methods of CP1dB and IIP3 calculation have been developed and have been realized using LabVlEW software platform. The proposed CP1dB calculation method is based on cubic spline interpolation of a dynamic characteristic of the device under test (DUT). This approach allows the user to reach accuracy about 0.1 dBm. That is comparable with an instrumental accuracy. This result can be reached because of the small procedural error and the algorithm robustness to accidental errors of experimental data. The method of the IIP3 calculation is based on solution of the extrapolation problem when the linear part of the DUT dynamic characteristic is described in analytical form. An automatic correction of the input signal level to preserve the linear regime of the DUT is the feature of methods. The measurement set to measure IIP3 and CP1dB has been assembled and its efficiency has been verified experimentally. For this purpose the CP1dB and IIP3 of pseudo morphic high electron mobility transistors (pHEMT) have been determined. The obtained values of CP1dB and IIP3 are of 6.5dBm and 20dBm respectively in 5Ghz frequency range.