2.4 GHz Ultra-Low Power Direct Digital-to-RF CMOS Transmitter for Biosensing Applications.

This paper presents a low-power and low-complexity direct digital-to-RF transmitter architecture, suitable for biosensing applications. The RF front end of the transmitter is based on a ring oscillator, whose output phase is modulated through the charge-to-phase mechanism using a charge injection block. Hence, the phase shift keying (PSK) modulation can be performed directly in the RF domain. Post-layout simulation results show that the transmitter is able to collect, process, and transmit sensed data with the maximum data rate of 20 Mbps and an error vector magnitude (EVM) of smaller than 3.5%, while dissipating the DC power smaller than 0.5 mW. The results demonstrate that the proposed transmitter architecture is effective for wireless biosensing applications.