Quad-channel broadband compact multi-antenna GNSS down-converter for high-reliability navigation

A high-reliability broadband high-linearity down-converter for multi-antenna global navigation satellite system (GNSS) receiver is presented in this paper. Based on direction-of-arrival estimation, the multi-antenna GNSS receiver can separate the GNSS signals from the interfering signals and suppress harmful broadband radio frequency interferences. To drive the off-chip 50 omega resistive load and meet the stringent requirements of linearity, a quad-channel down-converter with a broadband common-gate low-noise transconductance amplifier, current-driven passive mixer and novel bridge mode transimpedance driving amplifier have been proposed to contruct the multi-antenna receiver. The operating frequency of this down-converter is from 1.15 to 1.65 GHz, covering all bands for global positioning system (GPS), Beidou navigation satellite system (BDS), global navigation satellite system (GLONASS) and Galileo. The measured results show that the proposed quad-channel down-converter achieves +38 dBm output 3rd order intercept point (OIP3) and +17 dBm OP1dB (output-referred 1 dB compression point), 9.5 dB to 12.9 dB noise figure (NF) across the variable gain of 10 dB to 27 dB and approximately 47 dB channel isolation.