Towards a Fully Passive Radio Receiver with an Integrated Capacitive MEMS Speaker

In this work we present a passive radio receiver that integrates a capacitive MEMS speaker with a square loop antenna, enabling direct conversion of amplitudemodulated RF signals into audible sound without active electronics. The proof-of-concept prototype, that combines a PCB antenna with commercial microcantilever arrays, achieves SPL up to 59 dB at 1.8 kHz for a transmitted RF power of 37 dBm and maintains levels above 50 dB at distances up to 30 cm. Mechanical oscillations of the microcantilevers were optically measured, confirming efficient electromagnetic-to-mechanical transduction. The approach demonstrates the potential of MEMS-based passive receivers for compact, low-power audio systems and future integration into wearable devices.