Planar Spiral Inductor In Rf Ics

With the rapid growth of the wireless communication markets, radio frequency integrated circuits (RFIC) is recognized as a fascinating candidate to meet the demands of low-cost, high integration, and mature technologies. To date, most research on Silicon RF circuits is focused on Silicon RF design including some key blocks, and the performance of it is in creasing.Planar inductors become one of the most critical components in RF ICs, and it is usually fabricated in square, rectangular, octagonal, or circular shapes. The research of planar inductors is reported in this dissertation. Major contents and results of the study are abstracted as following:At first, we obtained the improved inductance formula of square spiral inductors by synthetic asymptote. For other shape of spiral inductors, we introduced the concept of shape factor based on the improved square spiral CAD formulas by keeping the metal area, the turn width, the turn spacing, and the turn number unchanged. The above CAD formulas are simple, accurate, and give good physical insights. It is very useful for the design of practical RFIC circuits.In order to analyze the S parameters, Q factor and the lossy substrate of planar inductors effectively, Partial Element Equivalent Circuit (PEEC) method is used, together with three-dimensional Green's function and CAD formulas obtained by synthetic asymptote. The results agree very well with those by numerical results (e.g., IE3D).At last, we analyze the influence of the spiral inductors structure, dielectric constant and the substrate conductivity to the spiral, and give the explanation of each in details. Moreover, spiral inductors on two layer substrate (SiO₂ and Si) are analyzed for the Q factor.