The Design And Model Of Microwave Transmission Line In CMOS Process

Silicon-based CMOS process has the advantages of low cost, low power consumption and becompatible with the base-band IC module, which makes it easy to implement system-wide low-costmanufacturing and large-scale applications. But in the high-frequency band, its performance andnoise are still flawed. With the development of the semiconductor technology, the device featuresizes continue to decreasing, and the increasing frequency characteristics make up the electronmobility deficiencies. In the millimeter-wave systems, passive components are essentialcomponents. And transmission line is one of the most important passive devices. Because thetransmission lines with variable sizes and structures have the advantages of achieving the smallvalue inductance. Although in the low frequency band, the loss of transmission line is greater, in themillimeter wave band, its length is significantly reduced, and has a high Q value. Moreover, thetransmission line has ground loops, which can effectively reduce the adjacent circuitelectromagnetic coupling. In addition, transmission line plays a vital role in matching network inthe millimeter-wave integrated circuit design. In support of millimeter wave integrated circuitsdesigning in silicon-based CMOS process, this paper do a in-depth research in structures, features,models and parameter extraction methods of transmission lines.At first, this paper briefly describes some of the major millimeter-wave transmission lineperformance indicators, including the transmission line characteristic impedance, propagationconstant, dielectric constant and Q value. Particularly, four distribution parameters(R, L, G, C),which characterizes the transmission line performance, have been described detailed. Then we listedsix kinds of common millimeter-wave transmission lines, and simply introduce their merits anddrawbacks.After that, we introduce the three classic transmission line structures (microstrip line, coplanarwaveguide, grounded coplanar waveguide), and comparative analysis has been done for the threestructures under the same process. This paper focuses on the novel contraction of coplanarwaveguide (CPW). Firstly, we propose and design a new structure of slow-wave ground coplanarwaveguide, which is not only has a smaller loss, but also has greater effective dielectric constant, inorder to effectively reduce the chip area. Secondly, we transform the ground plane of GroundCoplanar Waveguide structure (GCPW). And propose an innovative semi-elliptical ground coplanarwaveguide structure, which has a higher Q value and greater design flexibility. Then we madeanother two new T-shaped semi-elliptical and V-ground coplanar waveguide structures, which madea signal line improvements compared to the grounded coplanar waveguide structure. Although the new T-shaped structures do not get the desired results, it provides a new way in designing themillimeter-wave transmission lines.At last, we establish the corresponding equivalent circuit model for different structures of themillimeter-wave transmission line, respectively, and proposed corresponding parameter extractionmethod, and all results were verified with measurements. First of all, we established equivalentcircuit model of interconnect structure on low resistivity silicon, and proposed the correspondingparameter extraction method, and measured the 0.18μm CMOS process on interconnect structure toverify the accuracy of our proposed model. Then, we established the corresponding equivalentcircuit models and parameter extraction methods for the microstrip lines with different structure ofthe ground plane. We build the relationship between the two models parameters used to imitate thecharacterization of dielectric loss. Finally, we have done a in-depth research in CPW structuremodeling and parameter extraction method. We summed up the law of multilevel modeling and theway to choose the least the model section. Based on this, we further optimize the equivalent circuitmodel of a single section to improve the accuracy of the model. At the same time, we proposed aaccurate parameter extraction method, and with the measurements of CPW structure on 90nmCMOS process, we verify the accuracy of the model and parameter extraction method.