Direct-conversion receiver for ubiquitous communications

Abstract

A direct-conversion receiver for a 2.4-GHz sensor network is described. The receiver is designed to operate in a Bluetooth system where slight changes are made in the radio parameters to meet the low power requirement. The receiver includes an LNA, downconversion mixers, a 90-degree phase shift circuit, analog filters, a 1-bit analog-to-digital converter, and a received signal strength indicator (RSSI). The receiver consumes 4.1 mA from a 1.2-V power supply and it achieves 43-dB voltage gain, 25-dB noise figure, -22-dBm IIP3, and +11-dBm IIP2.