Low Power OOK Transmitter for Wireless Capsule Endoscope

A new structure of on-off keying(OOK) transmitter with low power consumption and high data rate is proposed using a current-reused CMOS differential LC-VCO for wireless capsule endoscope application. The carrier frequency (440 MHz) of the transmitter is determined as the minimum loss frequency point considering the antenna loss and the loss property of human body, etc. The transmitter is able to output 0 dBm of power at the single-ended output to a monopole 50-Ohm antenna to meet the demands of high-data rate speed (40 Mb/s) and short range (15-cm) wireless communication. This transmitter, has been fabricated using 0.18-mum CMOS technology, consumes only 860-muA of current from a 3 V supply.