In-phase/quadrature （I/Q） mismatch is a key problem in zero intermediate frequency （ZIF） receiver architectures. Although integration and careful layout can alleviate I/Q mismatch, circuit and system level calibra...In-phase/quadrature （I/Q） mismatch is a key problem in zero intermediate frequency （ZIF） receiver architectures. Although integration and careful layout can alleviate I/Q mismatch, circuit and system level calibrations are also needed due to process variations and variable operating conditions. The amplitude im- balance between I/Q channels was calibrated using a modified R-2R ladder to achieve fine linear-in-dB variable gain. A downconversion mixer working in the 2,4-GHz band was developed for a wireless local area network （WLAN） ZIF receiver using 0.25μm complementary metal-oxide semiconductor （CMOS）. The twostage mixer configuration relaxes the tradeoff between noise and linearity. Experimental results verify the fine linear-in-dB variable conversion gain of the mixer, which can also be used as part of an automatic gain control （AGC）loop.展开更多
A new compact model has been introduced to model on-chip spiral transformers.Unlike conventional models,which are often a compound of two spiral inductor models（i.e.,the combination of two coupledΠor 2-Πsub-circuit...A new compact model has been introduced to model on-chip spiral transformers.Unlike conventional models,which are often a compound of two spiral inductor models（i.e.,the combination of two coupledΠor 2-Πsub-circuits）,our new model only uses 12 elements to model the whole structure in the form of T topology.The new model is based on the physical meaning,and the process of model derivation is also presented.In addition,a simple parameter extraction procedure is proposed to get the elements＇ values without any fitting and optimization. In this procedure,a new method has been developed for the parameter extraction of the ladder circuit,which is commonly used to represent the skin effect.In order to verify the model＇s validity and accuracy,we have compared the simulated and measured self-inductance,quality factor,coupling coefficient and insertion loss,and an excellent agreement has been found over a broad frequency range up to the resonant frequency.展开更多
文摘In-phase/quadrature （I/Q） mismatch is a key problem in zero intermediate frequency （ZIF） receiver architectures. Although integration and careful layout can alleviate I/Q mismatch, circuit and system level calibrations are also needed due to process variations and variable operating conditions. The amplitude im- balance between I/Q channels was calibrated using a modified R-2R ladder to achieve fine linear-in-dB variable gain. A downconversion mixer working in the 2,4-GHz band was developed for a wireless local area network （WLAN） ZIF receiver using 0.25μm complementary metal-oxide semiconductor （CMOS）. The twostage mixer configuration relaxes the tradeoff between noise and linearity. Experimental results verify the fine linear-in-dB variable conversion gain of the mixer, which can also be used as part of an automatic gain control （AGC）loop.
基金Project supported by the National Natural Science Foundation of China(No.61106024)
文摘A new compact model has been introduced to model on-chip spiral transformers.Unlike conventional models,which are often a compound of two spiral inductor models（i.e.,the combination of two coupledΠor 2-Πsub-circuits）,our new model only uses 12 elements to model the whole structure in the form of T topology.The new model is based on the physical meaning,and the process of model derivation is also presented.In addition,a simple parameter extraction procedure is proposed to get the elements＇ values without any fitting and optimization. In this procedure,a new method has been developed for the parameter extraction of the ladder circuit,which is commonly used to represent the skin effect.In order to verify the model＇s validity and accuracy,we have compared the simulated and measured self-inductance,quality factor,coupling coefficient and insertion loss,and an excellent agreement has been found over a broad frequency range up to the resonant frequency.
