Experimental 5-GHz RF Frontends for Ultra-Low-Voltage and Ultra-Low-Power Operations

This paper presents experimental CMOS RF frontends suitable for ultra-low-power and ultra-low-voltage operations. In order to achieve the desirable gain and linearity of the receiver chain at a reduced supply voltage, the current-reused bias technique and the multiple-gated transistors are employed. As for the transmitter frontend, a low-voltage double-balanced mixer is utilized to maximize the conversion gain. In addition, a differential-to-single-ended circuit is also included to increase the saturated output power. Using a standard 0.18-μm CMOS process, the proposed circuits are realized for 5-GHz RF applications with a supply voltage of 0.6 V. The fabricated receiver frontend demonstrates a conversion gain of 14.5 dB and an IIP₃ of -16 dBm with a power consumption of 2.1 mW, while the conversion gain and the output 1-dB compression of the transmitter frontend are 12.9 dB and -4.1 dBm, respectively, provided a dc power of 6 mW.