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 50Ω2 resistive load and meet the stringent requirements of linearity,a quad-channel down-converter with a broadband common-gate low-noise transcon-ductance amplifier,current-driven passive mixer and novel bridge mode transimpedance driving amplifier have been proposed to contruct the multi-antenna recelver.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.