LTCC Passive Devices Design And Modeling Research

High density multilayer substrate is the key factor of MCM(Multichip Module).LTCC(Low Temperature Co-fired Ceramic) has become a hot spot in the research of High speed and high density integration and encapsulation because of its unique advantages. Nowadays, several domestic departments already have built their mature microwave LTCC production line. But the LTCC modeling, database-creating and design platform research has been lagged behind relatively, which gravely restricts the ability to fast design and develop LTCC products.This thesis mainly comes from modeling and database-creating of the project Microwave LTCC Design Plat. In it, several microwave LTCC passive devices have been studied, then manufactured and modeled, based on which several miniaturization designs have been presented. The main research content is as follow:1. Commonly used structures of LTCC multilayer circuit are analysed. Several transmission line structures are introduced and their Analytical and empirical design formulas are provided.Some simulations and optimizations of interlamination and same-layer interconnection and transition structures are conducted.2. Several LTCC microwave passive device models are established. Operating features and index characteristics of microwave circuit,especially three-port and four-port devices,are analysed. Mapping relations between physical dimensions and index characteristics are established based on analytic and empirical formulas and combining with simulation and optimization.Then the simulation models of coupled line directional coupler,branch directional coupler,wilkinson power divider,rat-race electric bridge and Marchand balun are established.3. Several minimized LTCC microwave passive device are designed. The equivalent characteristics especially equivalent characteristic impedance and electrical length of interconnection via are analysed. Combining with the advantage of LTCC multilayer circuit technology,the quater wavelength transmission line is minimized using shunt stubs. Miniaturization technology is proved usable. At last,several miniaturization designs aiming at coupled line directional coupler,branch directional coupler and rat-race electric bridge are proposed. Those designs are extremely small in size and have good performance.4. Several microwave passive devices are fabricated. The efficiency of those device models is verified in comparision with thesimulation models.The relative merits of the miniaturization designs are analysed.Based on the test results,the defects and problems are analysed and some improvement are proposed.