LyceanEM is a Python library for modelling electromagnetic propagation for sensors and communications. Frequency Domain and Time Domain models are included that allow the user to model a wide array of complex problems from antenna array architecture and assess beamforming algorithm performance to channel modelling. The model is built upon a ray tracing approach, allowing for efficient modelling of large, low density spaces. LyceanEM is also being used for ongoing multidisciplinary research combining channel modelling and spatial mapping using computer vision. The flexible and efficient nature of the scattering model allows for exciting exploration of the signal sources in the local environment on low power computing devices. The benefit of this emphasis on rapid virtual prototyping is to allow the user to quickly establish the potential performance for a desired aperture and frequency, on a desired platform with relatively little design effort. Comparatively, the otherwise excellent commercial solvers like CST, HFSS, FEKO etc can provide excellent simulation fidelity, but require a significant design investment before the simulation can be run. This lack of coverage leads to an uncertain design process for antenna arrays in which the requirements for an antenna array can be specified without reference to the physical limitations imposed by the desired aperture size, location, polarisation, beamforming envelope etc. LyceanEM allows these factors to all be predicted rapidly, and the beamforming architecture to be simulated in a realistic way, providing crucial design insight at a low cost.