Co-Site Interference Analysis on Aerospace Platforms using Advanced Simulation Tools

Modern Aerospace, Naval and Defense platforms are overwhelmed with radiofrequency (RF) signals competing for spectrum. RF co-site interference has become a major problem due to the RF interference from jamming, radio stations nearby, or even from civilian communications such as mobile phones. It can be a problem on military platforms like surface warships, land vehicles, and aircraft where many different RF transmitting and receiving antennas must share a relatively small space. This can be a communication nightmare in which separate RF systems inadvertently step on each other's signals, causing an RF communication fratricide problem that can also be compounded by intentional or accidental RF jamming. It has become more important than ever to address these issues that arise due to RF co-site interference.In this paper, we present advanced simulation tools for antenna placement, antenna coupling and cosite interference on electrically large air platforms using Altair Feko and Wrap softwares. S-parameter coupling matrix of various antennas (both in-band and out-of-band) are computed using either full-wave solutions such as MoM, MLFMM or using asymptotic methods such as PO, RL-GO and UTD. Alternatively Coupling Loss Matrix, defined as the power ratio between powers at the terminals of the transmitting and receiving antennas can be computed using equivalent sources. S-Parameter matrix or Coupling Loss values are then used to study the parameters of co-site/collocation interference such as inter-modulation products, adjacent channel interference and harmonic interference. Furthermore, we will also discuss the options to mitigate collocation interference by adding appropriate filters.