A new bio-implantable transmitter topology for minimizing the antenna effects

Oscillator transmitters are desirable for very low power circuits, like bio-implantable ICs. In these transmitters the antenna is directly connected to the oscillator and no buffer or power amplifier is used to separate the antenna from the oscillator. A new oscillator circuit topology is presented in this article that can be used in an oscillator transmitter. In the proposed circuit the impact of the antenna on the oscillation frequency is minimized. The design issues and simulation results of the circuit in 0.18pm CMOS technology are presented. The simulations show that a change of 20% in the inductance of the antenna changes the oscillation frequency by 0.12% which is much less than a conventional.