Inter-Beam Modulation Prediction and Test for Multi-Beam Active Arrays with Beam-Hopping Capability

In recent years, multi-beam and beam-hopping antennas (for TDMA application) have become a standard in Space Industry. In such a way, new issues appeared when complex active antenna arrays with beam-hopping, multi-beam and other multiple features and capabilities have been developed. One of these issues is the inter-beam modulation or carrier related noise that appears on a fixed beam when other beams are in beam-hopping configuration. A well understanding of this issue and prediction methods are mandatory in order to apply any design prevention to avoid or mitigate inter-beam modulation effect as much as possible, fulfilling spurious system or subsystem requirements. In this paper, a simplified model of an active array will be introduced in order to explain, extrapolate and formulate inter-beam predictions. In addition, some measurements on a Multi-Chip-Module (MCM) with Beam-hopping multi-beam capabilities will be presented to correlate prediction and measurements. The both validated concept and approach can be properly extrapolated to more complex and larger active arrays by antenna designers.