An Ultra-Low-Power 9.8 GHz Crystal-Less UWB Transceiver With Digital Baseband Integrated in 0.18 µm BiCMOS

Abstract

This paper presents a fully-integrated IR-UWB radio, designed to operate within the limits of mm-scale micro-battery for cubic-mm sensor nodes. It includes an RF front-end, battery current limiter, baseband modem with I2C interface, and temperature-compensated relaxation oscillator for frequency generation without a crystal. The peak current draw from a modern mm-scale battery must be <;100 μA, below a radio's active power consumption. Thus, duty-cycling the radio only at the packet level is not an option, and so this IR-UWB radio includes an integrated modem which duty-cycles the RF front-end at the bit-level. A current limiter protects the battery from over-current conditions, and the radio operates from on-chip storage capacitance that is recharged between bits. The radio operates at 30 kb/s with a center frequency of 9.8 GHz. It consumes 291 μW average power in transmit mode while broadcasting 0.1 dBm pulses, and 306 μW in receive mode with a sensitivity of -77 dBm. The area of the radio is 2.73 mm<;sup>2<;/sup>.