A power-efficient injection-locked class-E power amplifier for wireless sensor network

In this letter, we present an injection-locked Class-E power amplifier (Class-E ILPA) suitable for 2.4-GHz wireless sensor network applications where the maximum transmit-power is typically about 10 dBm. In such a low transmit-power application, it is a great challenge to achieve a high transmit efficiency because the driving power and dc power consumption in the previous stage are no more negligible compared with the transmitted signal power. The proposed Class-E ILPA, which is fully integrated in 0.18-mu m CMOS technology, achieves the power added efficiency of 44.5% while delivering the output power of 11 dBm with drain efficiency of 49.3% at 1.2-V supply voltage. The measured locking range reaches 300 MHz with the input driving power of -6 dBm.