Four-channel broadband compact multi-antenna GNSS downconverter 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 wideband radio frequency (RF) interferences. To drive the off-chip 50Ω resistive load and meet the stringent requirements of linearity, a quad-channel down-converter with a broadband common-gate low-noise transconductance amplifier (LNTA), current-driven passive mixer and novel bridge mode transimpedance driving amplifier has 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 GPS/BDS/GLONASS/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), 9.5–12.9 dB noise Fig. (NF) across the variable gain of 10-27 dB, and approximately 47 dB channel isolation.