The research by Dr Abbasi and colleagues at the Centre for Wireless Innovation, Queen’s University Belfast, demonstrates the sensitivity of lens antenna arrays operating at millimetre-wave (mmWave) frequencies. Considering a Rotman lens array in receive mode, their investigation focuses on its most imperative defect: aberration of electromagnetic (EM) energy, because aberration leads to spillover of electric fields to neighbouring ports, reducing the ability of the lens to focus the EM energy to a desired port. With full EM simulations, they designed a 28 GHz, 13 beam-13 array port Rotman lens array to characterize its performance with the aforementioned impairment. Their findings show that the impact of aberration is more pronounced when the beam angles are close to the array end-fire. More critically, the corresponding impact of aberration on the desired signal and interference powers is also investigated for an uplink multiuser cellular system operating at 28 GHz. The presented results can be used as a reference to re-calibrate expectations for Rotman lens arrays at mmWave frequencies. Dr Abbasi of Queen’s University Belfast is one of five finalists globally in the Mobile World Scholar Challenge 2019 at MWC Barcelona.