Multi-mode piezoelectric radiation-based microantennas and miniaturized wireless sensing unit driven by bulk acoustic waves

Wireless sensing systems enable real-time, non-contact monitoring for next-generation intelligent platforms. Ideal wireless sensing systems feature compact, low power consumption, and long communication range. Here we report a miniaturized wireless sensing system with an integrated acoustic-resonance-driven piezoelectric microantenna (PE μ-antenna) with a 0.0196 mm² active area. The PE μ-antenna integrated on a film bulk acoustic resonator (FBAR) achieves dual-frequency radiation at 1.85 GHz and 3.91 GHz with gains of -32.96 dBi and -20.5 dBi, respectively. The μ-antennas achieve over four orders of magnitude radiation efficiency enhancement and volume reduction compared with existing piezoelectric transmitters. We further extend this approach to high-overtone bulk acoustic resonators with high quality factors for wireless sensing. The system enables temperature and strain sensing with a transmission range up to 1 m, demonstrating state-of-the-art miniaturization and transmission performance among wireless sensing systems. This work establishes a scalable platform for ultracompact wireless sensors and communication nodes in biomedical, wearable, and aerospace applications.