Modeling And Characterization Of Frequency-Dependent Parameters On Passive Devices In CMOS RFICs

With the development of wireless communication industry, people have more demands on the dimension, speed and power consumption of wireless products. Traditionally Microwave Monolithic Integrated Circuits (MMIC) and Radio Frequency Integrated Circuits (RFICs) are applied based on GaAs fabrication technology whose high cost restricts the generalization. With the push of the commercial market as well as the improvement of IC technology, studies of RFICs on Silicon substrate have become very hot area in industry and academia for the low cost of CMOS! As important elements in RFICs, passive devices have drawn much attention. The more improvements in system performance and operating frequency are achieved, the higher demands on performance of passive devices and model accuracy will be required.The main contributions of this paper are focused on frequency dependent characteristics of distributed parameters of passive devices, including on chip transmission interconnects, asymmetrical coupled transmission line and on-chip transformers.A general interconnect structure is presented and the serial impedance and the parallel admittance are analyzed, whose lumped element circuit model is verified in a wideband frequency through the measurement. Considering the skin effect and proximity effect, new structure model of on chip interconnect is proposed. Meanwhile circuit model for on chip asymmetrical coupled transmission interconnects are also extracted using Z-matrix method, with some algorithm modification for more general case.As for on-chip transformers, an analytical method based on partial element equivalent circuit (PEEC) is proposed to investigate frequency-dependent series inductance, series resistance, and mutual inductance of on-chip spiral transformers, which is compared with measured data. And some modeling methodology for extracting the parameters of multilayer transformer is introduced.