Short-Range Communication for Small Biomedical Implants using Magnetoelectric Effect

This paper introduces a technique, called monotonic energy transmission (MET), for short-range wireless data transfer from small implantable devices with millimeter (mm) scale dimensions to an external unit using the magnetoelectric (ME) effect. In the proposed technique, while low-frequency magnetic field is used to power an implant which integrates a small ME transducer, data is transferred by driving the ME transducer with an initiation and a suppression sinusoid, which are 180° apart in phase. Transmitting both sinusoids improves the data rate and minimizes the inter-symbol interference (ISI). This technique was combined with pulse position modulation (PPM) to further increase the data rate. This paper describes the theory behind the proposed technique and demonstrates its operation through measurements using a 6.56×2.63× 0.67 mm3 ME transducer fabricated with Metglas and PZT-5A as the magnetostrictive and piezoelectric layers, respectively. In measurements, 220 kbps data rate was achieved using a delay detection resolution of 1 ns with an ME transducer operating at 274 kHz.