Transmitter

In this chapter we present an 802.15.6 compliant 2360–2484 MHz multiband transmitter that digitally multiplexes the appropriate phases from an 800 MHz poly-phase filter output to generate π∕4 DQPSK signals at 2.4 GHz using injection locking. Modulation at one-third the RF frequency reduces the transmitter power consumption and enables channel selection using an integer-N PLL running at 800 MHz. The modulation technique does not require phase calibration and resolves the problems of traditional injection lock-based modulators. The prototype transmitter consumes 2.4 mW while delivering − 10 dBm RF power at the TX output resulting in an energy efficiency of 2.5 nJ/bit at 1.2 Mbps raw data rate. The measured RMS EVM for π∕4 DQPSK modulation is 3.21%.