An e2e Communication System Operating in the Electromagnetic Near Field

Ear to ear communication (e2e) is an excellent method to improve hearing aids. Given that the human head is inside the radio channel, this presents us with a major challenge, both in terms of efficiency and component geometry. This study provides an inductive communication platform for e2e including the selection of convincing topologies for antenna, transmitter, receiver and amplifier circuits. The test setup reaches 100 kBit/s at a distance of 20 cm. The power consumption amounts to 0.8 mA for transmission and 1.7 mA for reception. To achieve the gain needed for such a large distance, a receiver with a 4-stage amplifier is shown, which reaches 45 dB gain. For transmission a modified Hartley oscillator with OOK is presented which allows inductive counling at $f_{\text{res}}=3.175$ MHz.