Design of a dual-channel multi-mode GNSS receiver with a∑△ fractional-N synthesizer

<正>A 72 mW highly integrated dual-channel multimode GNSS（global navigation satellite system） receiver with aΣ△fractional-N synthesizer which covers GPS L1 and the Compass B1/B2/B3 band is presented.This chip was fabricated in a TSMC CMOS 0.18μm process and packaged in a 48-pin 3×3 mm2 land grid array chip scale package.This work achieves NF≤5.3 dB without an external LNA,channel gain = 105 dB for channel one （Compass B2 and B3 band）,and channel gain = 110 dB for channel two（GPS L1 and Compass B1 band）.Image rejection（IMRR） = 36 dB,phase noise is -115.9 dBc @ 1 MHz and -108.9 dBc @ 1 MHz offset from the carrier for the two channels separately.At the low power consumption,multibands of GNSS are compatible in one chip, which is easy for consumers to use,when two different navigation signals are received simultaneously.