A wireless phase shift keying transmitter with q-independent phase transition time

Inductive coupling is a common way to wirelessly transmit data to medical implants. In such applications, the carrier frequency is often limited to tens of MHz which is able to well penetrate the skin. To achieve high data rate, the number of carrier cycles used to modulate each bit should be as small as possible. This usually requires lowering the quality factor (Q) of the data transmission network, resulting in increased power dissipation. This paper presents a novel data transmitter using phase shift keying which can modulate the phase of the carrier within two carrier cycles, independent of the Q of the network; thus low power dissipation can be achieved. The transmitter is designed by taking advantage of the multiplefrequency resonant network of class-E power amplifiers. Design guidelines for such a Q-independent phase modulator are provided. Simulations and experimental results demonstrate that the phase modulator functions as expected.