Coupling Between Microstrip Lines With Finite （之间的耦合微带线和有限的）.pdfVIP

1 Coupling Between Microstrip Lines With Finite Width Ground Plane Embedded in Thin Film Circuits George E. Ponchak, Edan Dalton, Manos M. Tentzeris, and John Papapolymerou Abstract-- Three-dimensional (3D) interconnects built upon multiple layers of polyimide are required for constructing 3D circuits on CMOS (low resistivity) Si wafers, GaAs, and ceramic substrates. Thin film microstrip lines (TFMS) with finite width ground planes embedded in the polyimide are often used. However, the closely spaced TFMS lines are susceptible to high levels of coupling, which degrades the circuit performance. In this paper, Finite Difference Time Domain (FDTD) analysis and experimental measurements are used to demonstrate that the ground planes must be connected by via holes to reduce coupling in both the forward and backward directions. Furthermore, it is shown that coupled microstrip lines establish a slotline type mode between the two ground planes and a dielectric waveguide type mode, and that the connected via holes recommended here eliminate these two modes. Index terms—microstrip, coupling, crosstalk, FDTD I. INTRODUCTION Demand is growing for packaged Microwave Monolithic Integrated Circuits (MMICs) with greater functionality, lower cost, and smaller size. Furthermore, the digital processing and control functions of the system are now often incorporated into the same package as the analog circuits and MMICs. However, consumer, military, and aerospace components must fit into smaller areas. Thus, two-dimensional packages are no longer suitable for many of these applications. Instead, three-dimensional (3D) packages and integration technologies are required. A widely used, lo