Authors: Y. Wang, J. Yao, J. Luo, Y. Tang
Affilation: Tsinghua University, China
Pages: 508 - 511
Keywords: transmission line, transformer, balun, millimeter-wave
Passive elements (e.g., transmission line, transformer and balun) are widely used in Microwave/ Millimeter-wave (MMW) applications. Compared with time-consuming Electromagnetic (EM) simulation, equivalent-circuit compact models for these passive elements are more preferable for IC designers. However, most of existing equivalent-circuit models only cover low-frequency characteristic, which is not suitable for MMW applications. This is because establishing equivalent circuit model at MMW is more difficult as coupling effects and distributive effects are more complex. In this work, we develop new compact models for passive elements, which is suitable for MMW applications. The key feature is that the distributive coupling between the metal tracks and substrate effect are emphasized. For transmission lines, a new unified compact model for coplanar waveguide (CPW), grounded CPW and slotted CPW is proposed. The substrate coupling is modified by a parallel branch, which is the key to ensure the high-frequency accuracy. For transformers, the key is that the parasitic distributive effects and substrate coupling have been reevaluated for MMW application. The comparison between measurement and simulated result shows that the proposed model matches well with the measured data up to 67GHz, while traditional model is only accurate in the low frequency.