Application of the IMP signal phase relationship to reflector antennas and feeds

Previous published results on the origin of intermodulation products (IMP) have concentrated on measurement of the scalar amplitude of the IMP signals relative to the applied signal levels. When making complex amplitude and phase measurements of IMP signals it can be shown that the phase of the IMP signal generated at any point contact or junction can be predicted relative to the phase of the exciting source signals irrespective of the nonlinear characteristic, applied signal levels or the subsequent IMP amplitude. Work carried out by the authors into the microwave imaging of IMP sources on reflector antennas is believed to include the first published experimental results of measurements of both the amplitude and phase of IMP signals at microwave frequencies. The paper reports upon further investigations involving measurements of IMP signal phase and suggests how knowledge and application of the phase relationship could be an aid to predicting and evaluating the IMP field radiated by a reflector that is generating IMP upon its surface