Mutual Antenna coupling Test Approach for Spacecraft Applications

In the present scenario of satellites design, it is usual to see the antenna farm module of the spacecraft crowded with various kind of antennas. Different as function, up or down link, frequency range (UHF to Ka band) and power handling, all of these in the same space.One of the critical system parameters with this kind of complex configuration is the decoupling figure between the antennas.To limit radio frequency interference between antennas the use of filters before the LNAs can be useful, and the relative design in certain case could be challenging if the frequencies are really close. In this case the antennas decoupling factors can be decisive on the trade-off between various filters design solution. This design requests high values of decoupling, implying a proper choice of antenna placement and spatial attenuation between antennas.That's mandatory but could be not enough. It is needed to validate analysis with test and assess the right margin.This kind of test is, in a first approach, easy to do. An anechoic chamber, an RF spectrum analyser and various RF signal generators can be enough, if the chamber has the right anechoic performances. But if the decoupling requirement to be satisfied becomes demanding, the selected anechoic chamber could be not good enough and it should be too much cost impacting to rent a test facility with the right size and RF behaviour.