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 [1] for wireless capsule endoscope application. The carrier frequency (440MHz) 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 0dBm of power at the single-ended output to a monopole 50-Ohm antenna to meet the demands of high-data rate speed (40Mb/s) and short range (15-cm) wireless communication. This transmitter, has been fabricated using 0.18-mu m CMOS technology, consumes only 860-uA of current from a 3V supply.