Aircraft Transponder Signaling Concepts Using Multi-Mode Multi -Port Antenna

Flight transponder signaling standards must be continuously improved in light of increasing requirements for the safe integration of an increasing number of aircraft. Since the introduction of the airborne collision avoidance system (ACAS), transponders are not only a major part of the air surveillance systems of flight controls, but also communicating between each other. The purpose of this communication is the aforementioned collision avoidance. The most common current system is the traffic collision avoidance system (TCAS) II. Towards the integration of unmanned aerial vehicles, the ACAS Xu standard is under investigation. However, interrogations between different airborne transmitters help to improve the mutual information exchange between the vehicles. Hybrid beamforming with multi-mode multi-port antennas (M3PAs) is proposed to reduce the effects of interference from other users as well as ambiguities in the directional domain. The performance of different hybrid beamforming variants is compared and an example pattern measured in an antenna measurement chamber is shown.