A Low-Power Direct-Conversion Receiver with Improved Sensitivity using AC-Coupled Baseband Amplifier in 130 and 180 nm CMOS Technologies

Abstract

This paper evaluates the use of an AC-coupled amplifier as a base-band amplifier for a direct conversion receiver. Due to the importance oflow-power consumption circuits for modern applications, a passive-typeenvelope detector was used to perform the downconversion of the radiofrequency signal while the baseband amplifier improves the sensitivity.The circuits were designed and simulated using CMOS SkyWater 130nm and UMC 180 nm technologies. Open-source end-to-end ASIC designflow was used to obtain results to SkyWater technology. For both tech-nologies the results of each stage are presented, as well as a sensitivitycomparison for the envelope detector, and the sensitivity with the use ofthe amplifier. The power-consumption of the AC-coupled amplifier forSkyWater 130 nm was 1.8 μA and for UMC 180 nm was 0.9 μW . At theoperating frequency of 2.45 GHz, the receiver achieves a sensitivity of−58.5 dBm and −61.88 dBm for UMC and SkyWater technologies,respectively. The results are within the expectations and presented in theliterature. The AC coupled amplifier performs well as a baseband ampli-fier for a direct conversion receiver, improving sensitivity, amplifyingthe baseband signal in addition to adding low power consumption.