Micromachined multi-frequency ultrasonic transducer for implant-to-implant communication Mikrogefertigter Multi-Frequenz-Ultraschallwandler für die Implantat-zu-Implantat-Kommunikation

Ultrasound is not only suitable for imaging diagnostics but also for wireless communication inside the body, for example between active implants. For this application, the ultrasonic transducers used should be realized in a miniaturized form with a wide bandwidth. A capacitive miniaturized ultrasonic transducer with three resonant frequencies was fabricated using bulk micromachining and its frequency spectrum was analysed both in air and in a liquid. When operated in a liquid, the three resonant peaks broaden and merge into a single broad peak with a bandwidth of 1.7 MHz at a center frequency of 1.5 MHz. By selecting more widely spaced individual peaks, it should be possible to increase the bandwidth further. Due to the high bandwidth, the ultrasonic transducer is expected to be well suited for communication tasks.