Characterizing UAV airframe effects on mobile-band RF and EMF measurements under controlled anechoic conditions

Unmanned aerial vehicles (UAVs) are increasingly used to accelerate radio frequency electromagnetic field (RF-EMF) studies and performance assessments of mobile networks, particularly in locations that are difficult or hazardous to access. However, a conductive carbon-fiber airframe located in the reactive near-field of a receive antenna may detune the antenna and distort local field conditions, potentially compromising far-field assumptions. This study quantitatively investigates UAV-induced measurement errors in cellular frequency bands and their dependence on antenna–frame separation. A controlled laboratory procedure compares reference measurements with UAV-mounted configurations while varying the receive antenna distance from the airframe over the 700–3500 MHz range. Results indicate that, for the examined UAV platform and antenna placements, the measured differences relative to the reference are mostly below 3 dB across the investigated frequency range. Increasing the antenna–frame separation reduces these differences by approximately 1–1.5 dB for positions beyond 4 dot left parenthesis lamda slash 8 right parenthesis 4·(λ/8) 4 · ( λ / 8 ) compared with closer positions. These findings suggest that, under controlled conditions, UAV-mounted configurations can provide sufficiently accurate results for RF-EMF and performance assessment applications. However, the results are specific to the investigated UAV platform, antenna configuration, and laboratory conditions, and cannot be directly generalized without further validation.