Multicarrier Passive Inter-Modulation Prediction from 2-Carrier Measurements

Passive inter-modulation products between transmitted signals may prevent the correct operation of satellite receivers using the same antenna. In many cases, these passive products do not obey the classical rule of 3 dB/dB slope as a function of carrier input power and they cannot be modeled using the classical theory based on polynomials. This has prevented the exact computation of carrier to inter-modulation ratio in multicarrier conditions from 2-carrier measurements. This has led to the use of higher than necessary margins. We present non-analytic models that generate non-integer inter-modulation slopes identical to that obtained in measurements and permit to predict multicarrier results.