Low-frequency antenna arrays enable obstacle-penetrating communications, but their large physical footprint—a 4 × 4 array at 150 MHz requires 16 m2—prevents practical deployment. DeformRF enables portable, deformable arrays that compress to backpack-size yet maintain beamforming performance when deployed on flexible substrates. Our key insight is that data-driven methods can predict complex electromagnetic behavior under deformation without real-time simulations. DeformRF combines: (1) a 260,000-sample synthetic dataset mapping deformations to EM characteristics, (2) physics-inspired ML models achieving >94% prediction accuracy on average, and (3) smartphone-based 3D reconstruction requiring no infrastructure. In real-world experiments, DeformRF maintains beamforming gains within 1 dB of optimal despite severe deformation, while baselines degrade by 4–10 dB. For emergency response scenarios, our 4 × 4 flexible array achieves ±5° direction-finding accuracy when tracking signals through buildings, enabling practical indoor deployment of large low-frequency arrays.

Recent trends in flexible antennas and printed circuit boards present an opportunity to leverage deformable substrates such as textiles to deploy large UHF, VHF and ISM band antenna arrays in smart homes. Low-frequency large antenna arrays are rarely deployed in indoor settings due to their large size which makes them bulky and difficult to deploy. By embedding these arrays on existing surfaces such as curtains, we can improve through-wall sensing, beamforming for IoT devices equipped with low-power radios and indoor localization of Bluetooth tags.