Imagine a paper-thin sticker you can slap on a wall to listen to the room next door, and get this—it doesn't even need a battery.
March 16, 2026
Original Paper
RadEar: A Self-Supervised RF Backscatter System for Voice Eavesdropping and Separation
arXiv · 2603.12446
AI-generated illustration
The Takeaway
By vibrating in response to sound and reflecting radio waves, these tiny tags allow a receiver outside the room to 'hear' and even separate multiple voices. It effectively turns a simple, unpowered piece of foil into a high-tech spy microphone.
From the abstract
Eavesdropping on voice conversations presents a growing threat to personal privacy and information security. In this paper, we present RadEar, a novel RF backscatter-based system designed to enable covert voice eavesdropping through walls. RadEar consists of two key components: (i) a batteryless RF backscatter tag covertly deployed inside the target space, and (ii) an RF reader located outside the room that performs signal demodulation, voice separation, and denoising. The tag features a compact