Battery-free and wireless sensing presents a crucial challenge for large-scale and inaccessible infrastructure, where the difficulty of power supply severely limits continuous monitoring. Here, we develop a quartz-crystal-microbalance (QCM) technique that enables fully passive sensing at distances exceeding 50 m, far beyond the operating range of conventional battery-free sensors. This capability is enabled by a few-millimeter-sized MEMS-QCM sensor incorporating integrated antennas for efficient coupling between mechanical resonance and free-space electromagnetic waves. On the sensor side, an extended antenna of approximately 100 mm in length is connected to the MEMS-QCM to enhance wireless signal transmission. On the instrumentation side, Yagi–Uda antennas are employed for efficient signal reception and transmission. By exploiting controlled bending of an ultrathin quartz resonator, we achieve battery-free strain sensing at distances of over 50 m. We further introduce a new sensing mechanism for displacement measurement based on polarization relaxation on the electrodeless quartz surface, which also operates wirelessly and without an onboard power source. In addition, the platform is shown to be applicable to the wireless, battery-free hydrogen-gas sensing. These results establish a general framework for long-range, battery-free mechanical and chemical sensing, opening a path toward continuous, nondestructive monitoring of social and industrial infrastructure.

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• Mechanical deformation
• Piezoelectricity
• Device fabrication
• Micromechanical devices
• Nanoantennas
• Solid-state detectors
• Wireless communication networks
• Radio frequency techniques