Modeling And Design Of Inductive Devices In RFICs

With the development of communication industry, people have more demands on dimension, speed and power consumption of wireless products. The development of silicon fabrication technologies makes the CMOS technologies a possible substitute for the traditional GaAs fabrication technologies, which cost much in RF circuits. With the push of the commercial market as well as the improvement of IC technologies, study of the Radio Frequency Integrated Circuits (RFICs) and Microwave Monolithic Integrated Circuits (MMICs) on silicon substrate becomes very popular in industry and academia. As the important component, the inductive devices, such as inductor and transformer, play a key role in many applications, such as matching, filter and biasing. So the design and modeling of inductive device is very important in RF design.However, with the increasing of the operating frequency, the transmission line effects become more and more important. Meanwhile, the lossy substrate also degrades the performance of RF circuit. So many scholars have performed much research work and proposed some solutions, such as high resistive silicon substrate, suspended structure and patterned shielding. Furthermore, area is another focus in RFIC design. With the development of the technologies, we could use several layers to layout stacked structure in order to reduce the total area. However, the passive inductive devices remain the most area occupied component. So with further research, active inductor and transformer come out. Because constructed only with transistors, active structure scarcely consumes much area. Meanwhile, this active structure could provide relatively high Q value, and the inductive value could be tuned. With these merits, the active inductor and transformer have extracted many interests these years.For the passive inductive device is constituted by transmission line, in this thesis, we firstly study the modeling of the transmission lines, especially the patterned shielded transmission line, which is used extensively in inductive device. Then, we use the Partial Element Equivalent Circuit (PEEC) method to model the passive inductive device. The results from a MEMS balun show that our modeling method is very effective and accurate, even for a complex structure. Finally, we study the design of the active inductor and transformer and introduce the mind and the topology of the active inductor and transformer. With some design examples, we could know the advantage of the active inductive device more clearly.